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- RECOMMENDED Issued 2 0 1 1-06 

# PRACTICE Tire Pressure Systems- M aint ena n ce {A T IS) Type For Mediu m and Heavy Duty H ig h way Veh icles RATIONALE Today the world of mobility is served extensively by tires which are pneumatic in design . To function correctly these ti re designs need pneumatic pressure to derive th eir performance characteristics - optimum tread wear. fuel economy , ride quality , or fatigue life - hence the value of keeping the retained pressure at design levels ranks high . Wh ile peri od ic i nspection and the periodic action of adj usting the inflation pressure while a veh ic le is at rest has b een the no rm for ma intai ning pressure , th e need to hold tire inflation pressures closer to their des ign targets over ti m e , eve n w hile o perating a vehicle on the open road at highway speeds , becomes apparent The min i mum performance capabilities recommended in the following document support these needs. Within the medium and heavy-duty vehicle industry , the equipment supplier community has responded to the need to mai ntain inflation pressure , by developing various tire pressure systems which automatically re-inflate the t ire/wheel assemblies even wh ile operating on th e highway . Because these systems do not require any intervention or a ction by the o p e rator, operators will eventually come to rely upon these systems to maintai n tire inflation pressure . It is th erefo re i mportant that all ma rketed systems provide an adequate level of performance to assure cont inued i n-service safety. Tires and wheels are integral components of tire pressure systems . The system attributes for tire pressure systems described herein assume an appropriate fitment of tire and wheel for each application , and that these tire pressure systems are not dependent on the performance or physical cha racteristics of the tire or wheel components . The s ubstitution of one tire/ wheel assembly for another tire/wheel assembly of another configuration , appropriate for the ve h icle system , shall not render the tire pressure syste m inoperative, so long as i t prov ides a pne umati c chambe r fo r th e inflation gas . Unde r SAE document J2848-1 , the system functions and performance expectations for tire pressure mon itoring systems have been established. The subject document (SAE J2848 -2) addresses tire pressure maintenance systems for wh ich it is essential that the performance and communications to the driver be consistent with that established for tire pressure monitoring systems (see Figure 1) .

SAE Technical Standards Board Rules p rovide that: "This repo rt is published by SAE to adv ance the state o f t echnical and en gi neering sciences. The use o f this report is entirely volu nta ry , and its applicability a nd suitability for any pa rticular u se. including any patent infri n gement arising therefro m. Is the sole responsi bi lity of the user. · SAE reviews each technical report at least every five years a t which time it may be reaffirmed . revised . or cancelled . SAE i nvites your wntten comments and suggestions Copyright C 2011 SAE lntomatlonal All nghts reseNed No part of thos publication may be reproduced . stored on a retneva l system or

**traru~motted ,**  on any fonn or by any means. electronic. mechanocal . photocopying. reoordong, or otherwise, without the pnor wntt. en permission of SAE TO PLACE A OOCUM E NT ORDER : Tel : 877-606-7323 (Inside USA and C a nada) Tel : +1 724-776-4970 (outside USA) S AE WEB ADDRESS : Fax: 724-776-0790 Email: CustomcrScrvlcc@sao .org http :/twww. sae .org SAE values your inpu t To p rovi de f eedback o n this Tech nical Report, p l ease visit http :// www.sae .org/techn lcallstandards/J2848/2 201106

### SAE Oo\\ll)u;nhd ltolll '\I llllt.'lrt.t(IHII.tl I.\ \I< uJ111. I hur..**d.l\.J)t,.·\t.lllh~o.·r** IX.**~HI~** 

### J2848-2 Iss u ed JUN2011

CTIS**~-------~(Managem nt)** 

FIGURE 1- R ELATIO N S HI P OF T I RE PRESSURE SYSTEMS 

### Page 2 of 1 5

While tire pressure maintenance systems do not relieve the driver of his immediate responsibility to take the recommended ma i ntenance action , these systems must still keep the drive r informed of the status of the pressure level and make him aware when the system applied is no longer performing its intended function . This document incorporates the attributes of pressure maintenance systems into the management of tire inflation pressure while retaining the alerts and warnings so vitally important to the driver.

### SAE

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### 2.2 2.2 . 1 2 .2 .2 2 .2 . 3 2 .2.4 

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### J2848-2 Issued JUN2011 Page 3 of 15 TABLE OF CONTENTS SCOPE........................................................................................ . . .. ............... . ......... . . .................. ................. 4 Purpose ........................... . .......................................................... . ..... ........ .... . .............................. ....... .. . ........ 4 REFERENCES...................................................................................................... . ....................................... 4 Applicable Documents ...................................................................................................... . ........................... 4 SAE Publications. . . ............... . .......... ...... . .. ....... ........ .......... ..... .. .. . . .................................... . ......................... ... 5 ASTM Publication......... ..... ................ .... ....................... . ................................................................................ 5 Fe deral Publications ............................ ........... ............................. .... .............. .......... ........ .... .............. .... ....... 5 Re lated Pub lications ................................................... . .............. .... ................ ... ................ .. .......................... 5 The Tire and Rim Association Publication .................................................................................................... 5 ETRTO Publication ............. . .. . ............. .. . . . . .............. .. ................. .. ................................................................ 6 JATMA Publication ........................................................................................................................................ 6 ISO Publications............................................................................. . .............................................................. 6 ATA Publication ............................................................................................................................................. 6 Federal Publications ............. . ..................................................................................................................... . . 6 DEFI NI TIO NS ............................................................................................... ................................................ 7 Te rms .............. . ............................................................................................... .............................................. 7 Symbols a nd Abb reviations .......................................................................... . ............. . .. .. . ............................ 8 TIRE PRESSURE SYSTEMS- MA INTENANCE TYPE ............................................................................... 8 General System Requirements ........................................................................................... .......................... 8 Advanced System Requirements................................................................................................................ 10 Component Performance Requ irements - Valve s , Senso rs , Regulators , Control Modules, etc................ 1 0 Environmental ............................................................................... . ....... .... ........................... ........ . .............. 1 0 Corrosion.............................................................................................. . ...................................................... 10 Proof Pressure ....................................... .. ... ............. ...... ......... ... ................................................................. 11 TIRE PRESSURE SYSTEM ....................................................................... .. ........... ........ ........ ................... 1 1 System HM I Characteristics.. . ..... ..... ................. .......................... ............. ...... ...... . .......... . ....... ........... . . ....... 11 System Performance T hresholds ........................................................................................... .................... 1 2 Controls , Symbols, Switches ..... ........... ..... ................................................................................................. 12 Owner' s Manual I nformation . . ................ ... .................................................................................................. 12 AT IS SYSTEM - PERFORMANCE DEMONSTRATION ............................................................................ 1 3 Ve hicle Test ( Power Un it, Tra ilers, Dollies) ............................... . ............................................................... . 13 N OT ES ............... .. ....................................................................................................................................... 1 5 Marginal Indica .... . .................................................. . ... . ........... . . .. ............................ .... ................................. 1 5 RELATIONSHIP OF TIRE PRESSURE SYSTEMS .................................................................. .. ................ . 2 MAINTENANCE SYST E M OPERAT IN G RANGE ....................... .. ............................................................. 1 2IJ••\\IIh Ill Ill• 111 "\I lullr .II 111.d It\ \I c uliu. 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### SAE J284 8-2 Iss ued JU N2011 Page 4 of 15 1 . SCOPE This SAE Recommended Practice defines the system and component functions , measurement metrics , and testing methodologies for evaluating the functionality and performance of ground veh icle tire pressure maintenance ( ATIS} systems (systems whi c h automatically restore the inflation pressure to its specified level ) , and reco mmended maintenance practices for these systems within the known operating environments. These systems are recommended to address all serviceable tires as originally installed on a vehicle by the OEM and/or specialty vehicle manufacturer, and for the aftermarket (including replacement or spare parts) are recommended (bu t optional) to address all tire/rim combinations installed after initial veh icle sale or i n- use dates . This document is applicable to all axle and all wheel combinations for the following vehicle types - single unit powered vehicles exceeding 7257 kg (16 000 lb) gross vehicle weight rating (GVWR) , and multi-u n it vehicle combinations , up to three towed units, which use an SAE J 560 connector for power and/or communication , or equivalent successor connector technology . For combination vehicles including two or more trailers , the dolly axles are also included . The included veh icles can be newly manufactured veh icles or existing vehicles , fitted with air or hydraulic braking systems. SPECIAL NOTE : Equipment known as ' dual tire equalizers' are commonly used with this category of vehicles . When employing an AT IS system , dual tire equalizers systems are not recommended as they run counter to the purpose of the maintenance system . NOTE: The following systems are not being addressed in this ed ition of the subject document. 1 . The management system types and more mature/complex versions of maintenance and management types , to include on-board reporting/storage/retrieval data/control capabilities , will be addressed separately by future changes/additions to this document series. 2 . Tire pressure monitoring systems- These systems have been addressed under SAE J2848- 1 . 1 . 1 Purpose The installed systems for the ma intenance of tire inflation pressure defined herein are on-board vehicle systems only. The mai ntenance type systems described herein may be controlled mechan ically, electronically , and/or a combination of both , and should include sensing , restoring , and indicating/communicating , and recording (when specified by the OEM or user ) capabilities . The design approach taken is expected to support the purpose and performance objectives of such a maintenance type system , and to function within the intended operating environment and design configuration of the vehicle itself. The t ire pressure system of the maintenance (AT IS) type is intended to (1 ) restore the tire's lost inflation gas , measured as inflation pressure , relative to the SSP (specified service pressure) under each operational stage ; (2) ma i nta in th e specified service pressure level for the typical range of ambient conditions ; and (3) provide the dr iver with indications of low uncorrected pressure(s) and system malfunction . 2 . REFERENCES 2 . 1 Applicable Documents T he following publications form a part of this specification to the extent specified herein . U nless otherwise indicated , the latest issue of SAE publications shall apply .U11\\lll1•11 Ill• "'"'-\I ltl r 11111 1•11\ \It uhn. l'111r'd t\ IJ \. nt l'!i .:!nt I 

### SAE J2848-2 Issued JUN2011 

### Page 5 of 15 2 . 1 . 1 SAE Publications Available from SAE International , 400 Commonwealth Drive, Warrendale , PA 15096-0001 , Tel : 877-606-7323 (in side USA and Canada) or 724 -776-4970 (outside USA ), www.sae .org . SAE J560 Primary and Auxiliary Seven Conductor Elec trical Connector for Truck-Trailer Jumper Cable SAE J1211 Handbook for Robustness Validation of Automotive Electrical/E lectronic Modules SAE J1455 Recommended Environmental Practices for Electronic Equipment Design in Heavy- Duty Vehicle Applications SAE J1 609 Air Reservoir Capacity Performance Guide- Trucks and Buses SAE J1939 Recommended Practice for a Serial Control and Communications Vehicle N etwork SAE J2334 Laboratory Cyclic Corrosion Test SAE J2402 Road Vehicles- Symbols for Controls, Indicator s , and Tell-tales SAE J2721 Recommended Corrosion Test Methods for Commercial Veh icle Components SAE J2848- 1 Tire Pressure Mon itoring Systems - For M edium and H eavy Duty H ighway Vehicles 2 . 1 . 2 ASTM Publ ication Available from ASTM Internationa l , 100 Barr Harbor Drive , P .O . Box C700 , West Conshohocken , PA 19428-2959, Tel : 610-832-9585 , www.astm .org . ASTM B 117 Salt Spray ( Fog ) Testing 2 . 1 .3 Federal Publications Available from Federal Motor Carriers Safety Admin istration , Un ited States Department of Tra nsportation , 1200 N ew Jersey Avenue , SE , Washington , DC 20590 , Tel : 1 -800-832-5660 , www.fmcsa .dotgov. Commercial Vehicle Tire Condition Sensors ( FMCSA - Dec. 2003) T ire Pressure Monitoring and Maintenance Systems Performance Report ( FMCSA - Jan . 2007) 2 .2 Related Publications The following publications are provided for information purposes only and are not a required as part of th is SAE Technical Report. 2 .2 . 1 The Tire and Rim Association Publication Available from The T ire and Rim Association , 175 Montrose West Avenue , Suite 150 , Copley , O H 44321 , Tel : 330-666- 812 1 , www .us-tra .org . T ire and Rim Year BookUn\\lllt uh I 11111'\l lllh.ll 11• •••h\ \I( uhn 111111'1 IJ"\t nl" lh 'IIJ 

### SAE J2848-2 Iss u ed JUN 2011 Page 6 of 15 2 .2 .2 ETRTO Publication Available from The European Tyre and Rim Technical Organisation , Secretariat, Av. Brugmann , 32/2 , B- 1060 Brussels, Belgium , Tel : +32-2-344-40-59 , www .etrto.org . ETRTO Standards Manual 2 .2 . 3 JATMA Publication Available from the Japan Automobile Tyre Manufacturers Association , 8 Floor, No. 33 Mori Bldg ., 3-8 -21 Toranomon , Minato-ku , Tokyo , 105-0001 Japan , Te l: 81-3-3435-9094 , www .jatma .or. jp . JATMA Year Book 2 .2.4 ISO Publications Available from American National Standards Institute , 25 West 43rd Street. New York , NY 10036-8002 , Tel : 212-642- 4900 , www.ans 1 org . ISO 7000 Graphical symbols for use on equipment- I ndex and synopsis ISO 2575 Road Vehicles-Symbols for controls , indicators and tell -tales ISO / IE C 2575:2004 Road vehicles . Symbols for controls , indicators and tell-tales 2 .2 .5 ATA Publication Available from Ame rican Trucking Associations Headquarters , 950 N orth Glebe Road , Suite 210 , Arlington , VA 22203- 4181 , Tel : 703-838-1700 , www .truckline .com . ATAITMC RP-235A Guidelines for Tire Inflation Pressure Maintenance (2008} 2 .2 .6 Federal Publications Available from Federal Com mu nications Commission , 445 12th Street, SW, Washington , DC 20554 , Tel : 1 -888 -225-5322 , www.fcc .g ov . 4 7 CFR Part 15 Te lecommunications - Federal Communications Commission- Radio Frequency Devices Available from the Federal Register, National H ighway Traffic Safety Administration , 400 Seventh Street , SW, Washington , DC 20590 , www. nhtsa .dot.gov . T itle 49 Code of Federal Regulations Federal Motor Vehicle Safety Standards- Part 571 FMVSS 101 FMVSS 120 FMVSS 105 FMVSS 135 FMVSS 121 Controls and Displays T ire Selection and Rims - Tire selection and rims for motor veh icles w ith a GVWR of more than 4 ,536 kilograms (10 ,000 pounds) . Hydraulic and Electric Brake Systems Light Vehicle Brake Systems Air Brake Systems

### SAE J2848-2 Issued JUN2011 Page 7 of 15 3. DEF INI TIONS 3 . 1 Terms 3 . 1 . 1 Baseline Temperature The temperature condition when the tire's contained air, the tire' s interior structure , and the adjacent ambient a ir temperature are the same 3. 1 .2 Standard Tire Mounting The action of assembling a tire and its specified wheel by button-holing the tire's beads over the wheel's flanges using a mechanized , rotating bead bar, or manual mounting tools . 3 . 1 .3 Specified Service Pressure (SSP) The 'cold ' pressure level for a tire/wheel assembly defined by the vehicle manufacturer or tire manufacturer for the intended service conditions (load, speed , etc.) of a given vehicle . 3 . 1 .4 Operational Service Pressure (OSP) The actual pressure level of the tire/wheel assembly at any point during service whether at ambient or at elevated temperature due to rolling under load . 3. 1 .5 Self Diagnostic A device function by which an analysis of system readiness can occur resulting in a positive or negative outcome . 3. 1 .6 Tire Pressure System A group of interacting components whose purpose is to measure , directly or through other parameters which correlate to pressure , the pressure level of the tire/ wheel assembly . 3 . 1 .7 'ATIS ' A generic term for tire pressure systems of the maintenance type which when fitted to a vehicle (1) sense the drop in gauge pressure level in a tire/wheel assembly directly or indirectly, (2) provide a one-way flow of inflation gas into each assembly , and (3) restore the gauge pressure reading to the specified level. 3. 1.8 Low Pressure (re-inflate) Threshold A change of pressure ( .A P) relative to the OSP indicating an actual loss of inflation gas from the tire/wheel assembly , or as a change in a parameter(s) which directly relate(s) to the actual loss of inflation gas , which serves as a trigger for activating the installed tire pressure system 's response . 3. 1 .9 Minimum Activation Pressure (MAP) A gauge pressure reading below the SSP which serves as a trigger for activating the installed tire pressure system 's response, and defines the low pressure threshold regardless of the actual loss of inflation gas . 3 . 1 . 10 Human Machine Interface (HMI) The device(s) which serve to bring about an understanding or communication between a human and a machine concerning the status of the monitored parameter(s) .lln\\llln hI 11111"\l

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### SAE J284 8-2 Iss ued JUN 2011 Page 8 of 15 3 . 1 . 11 Cold Tire Inflation Pressure Tire pressure at the prevailing ambient temperature . in the absence of any pressure build-up due to tire usage. 3 . 1 . 12 Quasi-stationary Vehicle creeping forward at very low speed , causing at least one full revolution of each installed tire/ wheel assembly . 3 . 1 . 13 Gross Vehicle Weight Rating (GVWR) Means the value specified by the manufacturer as the loaded weight of a single motor vehicle . 3. 1 . 14 Gross Combination Weight Rating (GCWR) Means the value specified by the manufacturer as the maximum loaded weight of a combination (articulated) motor vehicle . 3 . 1 . 15 Lockout System function whereby the re-inflate system is isolated from the brake pressure supply reservoir preventing a further reduction in th e pressure level of th is reservoir. 3.2 Symbols and Abbreviations OUT - Device Under Test ATIS - Tire Pressure Ma intenance System TPMS - Tire Pressure Monitoring System SSP - Specified Service Pressure OSP - Operational Service Pressure HMI -Human Machine I nterface MAP - Minimum Activation Pressure FMVSS - Federal Motor Vehicle Safety Standards FMCSA - Federal Motor Carrier Safety Administration 4 . TIRE PRESSURE SYST EMS - MAI NTENANCE TYPE 4 . 1 General System Requirements 4 . 1 . 1 The ATIS system is a system mechanically or sensor activated by a demand for compressed air in one or more of the tire/wheel assemblies , vehicle rolling and optionally , vehicle stationary . 4 . 1 .2 The AT IS system should be capable of restoring the lost inflation gas (adding of compressed gas) to each tire/wheel assembly of the power unit, tra iler, or dolly unit so equipped , without negative effects to any other airpowered systems or accessories on each vehicle so equipped . 4 . 1 .3 Even with a AT IS system installed , one must still be able to manually check , inflate , or deflate each tire/wheel assembly , and have access to the inflation valves without the use of non-traditional tools , and certainly not specialty tools , or adapters.U I I 1 n '\1 lui 1 lt•t II• \IC til lh111' a\ I 

### SAE J2848-2 Issued JUN2011 Page 9 of 15 4 . 1.4 While the ATIS system may be self-responding, these systems should still have the capacity (1) to indicate to the operator a low pressure condition in any of the tire/wheel assemblies connected to the air system and (2) to warn the operator of any continuous pressure drawn-down condition but not later than the point of system isolation from the supply reservoir. This indicator circu it may be activated by either turning the ignition "ON" in the case of the power unit , or by making a power connection in the case of a trailer or dolly unit , or may use a combination of vehicle power and self-power. 4 . 1 . 5 The ATIS system when installed on any one of the following vehicle types - single unit powered vehicles exceeding 7257 kg (16 000 lb) gross vehicle weight rating (GVWR) , and/or trailers (with dolly axles as applicable) which use an SAE J560 connector for inter-vehicular power and/or communication , or equivalent successor intervehicular connector technology - should be capable of maintaining all axle and all wheel combinations . 4 . 1 .6 The ATIS system should contain one or more air check valve(s) (1) which are capab le of isolating the re- inflate system from each rapid pressure loss assembly, and from an assembly during the action of tire/wheel changeout, (2) which are capable of isolating the air brake system reservoir (where appropriate) from the re-inflate system to meet the criteria of 49 CFR Part 571 . 121 (FMVSS 121), 49 CFR 393 Subpart C , and 49 CFR 393 .207 , and (3) with sufficient safeguards to prevent back flow into the applicable truck or bus , prime mover (tractor) , and/or trailer vehicle air system . 4 . 1 .7 The vehicle compressed air supply which is used to re-inflate the tire/wheel assembly should supply 'clean , dry ' air to the ATIS system , and will have sufficient capability to operate the ATIS system as intended by the system manufacturer to support the volume demand of the fitted tire/wheel assemblies . (On legacy vehicles , a pressure step-up or booster unit may be required.) 4 . 1 .8 With regard to a system's function, the tire pressure system manufacturer should specify accuracy, nominal level/reading, and normal operational range for included components and make such information available for all users. Ultimately, the accuracy of the system components should be sufficient to keep the inflation pressure within the specified pressure range . 4 . 1 .9 The tire pressure system sampling rates and sensor capabilities should be sufficient to support the communication requirements at the HMI (see Section 5 ) . 4 .1 . 10 The ATIS system should be configured to add inflation gas. but, by definition , is not required to reduce the inflation pressure . 4 . 1 . 11 If used, the wired or wireless communication link between a power unit and trailer(s), should perform to the guidelines delineated in SAE J2848-1 . 4 . 1 . 12 If used , the link between a wireless pressure sensor and its receiving module should perform to the guidelines of SAE J2848-1. 4 . 1 . 13 The specified service pressure (SSP) , or reference pressure , is determined in cooperation with the vehicle OEM or specialty manufacturer and the tire manufacturer, based on the vehicle capacity , the maximum applied axle or wheel position loads , and operating conditions . For reference purposes only , an industry accepted method for determining the appropriate specified service pressure has been documented in the American Trucking Association 's TMC RP-235 : Guidelines for Tire Inflation Pressure Maintenance . 4 . 1 . 14 The ATIS system should have the capability to allow the initialization and adjustment of the system 's set point for the SSP in the field by authorized personnel. On the other hand, should the system be disabled by error or through tampering , the ATIS should provide to the driver an indication that the reinflation system has been isolated from the supply reservoir. 4 . 1 . 15 The ATIS system should have the flexibility of design such that the removal or replacement of a tire/wheel assembly can be accomplished in a safe manner and will not render the system inoperat ive .l)u\\1Jin.lll\·dltol11"\l lllh'llltl11111.tlh\ \IC ••lt11. lhlll.,tl.n.IJL'-''11111\1 IN.2flll 

### SAE J2848-2 Issued JUN2011 Page 10 of 15 4 . 1 . 16 For operators who use nitrogen inflation upon initially filling each tire , it is acceptable to top-off such assemblies using compressed air from the ATIS system should authorized personnel so desire. 4 . 1 . 17 The typical operational conditions and configurations for which AT IS systems should function properly (during either the sensing or the re-inflate mode) are outlined below: a . Speed -The tire pressure system should function installed in a vehicle while rolling at any vehicle design speed when sufficient air pressure is available, and optionally, while resting stationary . b . Road Surfaces - T he tire pressure system should function installed in vehicles operating on all improved road surfaces , unless specified otherwise. c . Maneuvers- The tire pressure system should function during all safe driving maneuvers. d . Loading- The tire ·pressure system should function properly across the full loading range of the powered vehicle , and the full loading range of the trailer unit(s) per the vehicle manufacturers' recommended limits. e . Temperature - The tire pressure system should function when properly installed and used as intended on vehicles specified under 4.1.6 operating in ambient temperatures ranging from -40 ° C (-40 ° F) to 55 

# o c (131 ° F) , and under the full range of system operating temperatures when supplied with clean , dry air. 4 .2 Advanced System Requirements Should the installed ATIS system be a full featured electronic system (sensor within every wheel assembly initiating a reinflation actio n , communication on the dashboard of the ongoing status of the maintenance system , wireless communications , etc.) , refer to SAE J2848-1 for the associated system functions , measurement metrics , and testing methodologies. 4 .3 Component Performance Requirements- Valves , Sensors, Regulators , Control Modules , etc. 4 .3 . 1 Environmental It is the intent that electronic device(s) and mechanical components that are mounted in/on the tire/wheel environment or on the vehicle should be sufficiently robust, with typical design safety factors , and 'hardened ' by design , be capable of successfully completing all the tests - thermal cycling, thermal shock , humidity, altitude. mechanical shock, drop, mechanical vibration, and combinations of these conditions. The recommended test method for these conditions is defined in SAE J 1455 . The functionality of the device(s) under test (OUT) should be verified before and after testing . Additionally, each OUT should be visually inspected for damage before and after testing . Unless otherwise specified , each OUT must be at ambient atmospheric pressure , relative humidity, and temperature unless specified otherwise for each test. 4.3 .2 Corrosion The identification of potential physical contaminates , and the mitigation/elimination of their corrosive effects is critical to both performance and longevity of all tire pressure systems and related hardware . Depending on system type , the design and performance of the system components must be addressed in regards to potential system contaminants : for example, power connections; sensing units ; component attachment points/locations; inflation supply and source , and check valves . The recommended test methodology for physical contaminates is to apply the laboratory conditions for corrosive events and cycles , and the chemical mixtures (solutions) as defined in SAE J2 721.• I "\I I I II \ c 

### SAE J2848-2 Issued JUN2011 Page 11 of 15 4 .3.3 Proof Pressure Though the service pressure for most tire pressure systems is as specified on the tire placard, there are instances when the device can be exposed to pressure levels above those listed . For pressure sensing devices. it is important that these devices continue to function even after exposure to elevated pressures, and that the device itself does not fail compromising the ability of the tire/wheel assembly to hold pressure . A recommended test method is to attach the OUT to a pressure vessel. Pressurize the vessel to not less than 150 psig unless superceded by a higher maximum worl<ing pressure by the vehicle OEM . Maintain the applied pressure for 30 min , then release to ambient atmospheric pressure . and immediately test for functionality once pressure and temperature are stable . 

### 5 . TIRE PRESSURE SYSTEM The tire pressure system , maintenance type, should employ a design-for-use approach to make its operation selfdirected . In other words , th e human-machine-interface envelope should require as little operator inputs as may be economically viable within state-of-the-art technology , in order to mitigate or eliminate the potential for intentional and unintentional errors and/or vehicle operator-induced/mainta iner-induced damage. 5 . 1 System HMI Characteristics 5 . 1. 1 Warning Devices The ATIS system should be capable of communicating a warning to the driver, and continue to warn until the pressure has been restored , for the following conditions . a . a low pressure condition , namely whenever the pressure level in any tire/wheel assembly drops below the system 's MAP , b . any continuous pressure drawn-down condition but not later than the point of system isolation from the supply reservoir, namely the minimum pressure for brake system operation . 5 . 1 .2 A single driver warning device is desirable , however, lacking such an arrangement, each additional unit (trailer or dolly) should have at least an external warning device visible to the driver. 5 . 1 .3 The minimum configuration of the device for communicating a warning to the driver should be a panel with optical telltale(s) which communicate by their operational mode(s) a low pressure condition , or the isolation of the reinflation system from the supply reservoir. Regardless of the design solution, the telltale must illuminate whenever the system is not at rest, i .e ., flowing or attempting to flow compressed air to a tire/wheel assembly . 5 . 1.4 Location The indicator panel should always be available for the driver's viewing . Whether available on the dashboard or other location within the cab , or on the exterior of the trailer, the location is optional. 5 . 1.4 . 1 If a dashboard display option is selected , this communication must be marked appropriately for the system installed, and carry different action (manual} instructions than that of a tire pressure monitoring system . 5 . 1 .4 .2 If a trailer display option is selected, this communication must be visibly available to the driver/operator for each trailer pulled , even if multiple trailers are involved .))ti\\Jl)H.tthdlltlll,\1 lUhlll.dHIII,Ih\ \((nflll IIHH,lll\ Jh\t.l1ihll**l.S.~It(** 

### SAE J2848-2 Issu ed JUN 20 11 Page 12 of 15 5 .2 System Performance Thresholds 5 .2 . 1 The response thresholds for a tire pressure system of the maintenance type are defined as follows (see also 4.1 . 13 for the SSP) : a . The minimum activation threshold for the re-inflate function should not be less than 97% of the tire 's specified service pressure (SSP) . b . The optimum activation threshold for the re-inflate function is 97% of the tire's operational service pressure (OSP) in its operational state (OSP-3% curve) . c . The re-inflate function should de-activate no later than the pressure level associated with the operational service pressure (OSP) in its operational state (OSP curve) . 

## Tire Pressure Maintenance System Sustaining the pressure within a range

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## f-. Time (VehiCle Rolling) SSP= Specified Service Pressure OSP =Operational Service Pressure OSP in its operational state (respo nd ing to temperature) MAP 

## = M in imum Activation Pressure 0 timum Activation Thresho ld FIGURE 2- MAINTENANCE SYST EM OPERATI NG RANGE 5 .3 Controls, Symbols , Switches 5 .3 . 1 If the use of an ATIS system switch or button requires the driver to first consult his owners manual , a sticker on the display or a message on one of the first display screens upon activation should direct him accordingly. 5.4 Owner's Manual I nformation 5.4 . 1 For each system installed, it is essential that a full set of instructions and explanations be made available to the Operator in the Owners Manual. This information should include the type of system applied to each unit (tractor or power vehicle) , its function , how to interpret the data panel display, and necessary system maintenance actions . This information should be specific to and accompany each vehicle , or trailer unit. 5.4 .2 Even with an ATIS system installed , it is incumbent upon the operator or fleet maintenance responsible to conduct a check of the inflation p ressure of each assembly and to restore the inflation pressure to the specified level , prior to operating the vehicle on the highway.II 1 I 1 ll1 1 "\1 l1 1 I •II I \ ( o h 1 I 1 I, I IS 

### SAE J2848-2 Iss ued J UN2011 Pag e 1 3 of 15 6 . ATIS SYSTEM - PERFORMANCE DEMONSTRATION The demonstration of the response and performance of a ATIS system should be specified i n the OEM test p lan in relation to the vehicle type or vehicle combination . In the event that no OEM test plan has been specified, the procedure defined below may be used . This procedures is structured to validate that the system as designed and used as intended meets or exceeds the defined response characteristics of this specification, namely , (1) can communicate at the driver/operator indicator panel a condition of low pressure in a tire/ wheel assembly(ies) or the isolation of the re-inflation system from the supply reservoir, and (2) maintains the inflation pressure within the acceptable operating pressure range . Regardless of test method used , appropriate safety procedures and safety equipment must be utilized . 6 . 1 Vehicle Test (Power Unit , Trailers, Dollies) 6 . 1 . 1 Test Setup The test vehicle should be equipped with an operationally ready ATIS system , and if the test vehicle is a trailer, with the trailer attached to a power unit and all associated connections made . a . Set the tire pressure to the operational service pressure for the vehicle(s) under test. Condition the vehicle for 1 h outdoors- stationary, and tires shaded . The ambient temperature should not vary mo re than 20 oF (11.11 ° C) over the test interval. b . Reset the tire pressures. Consider the tire stabilized if within ± 1 psi after 10 min . c . If applicable , conduct a reset of the ATIS system in accordance with the instructions specified in the vehicle owner's manual. d . With the vehicle stationary and beginning with the ignition locking system in t he " Lock" or "Off' position , turn the ignition to the "On " or " Run " position . e . Allow the on-board compressed air system to reach its operational pressure level , and then command a release of the brakes on the tra iler allowing the flow of compressed air to the tire pressurization system . 6 . 1 .2 Test - Vehicle Stationary Phase I - The steps of Phase I should be conducted one tire/wheel assembly at a ti me , and with the vehicle stationary. If the ATIS system does not function with the vehicle stationary proceed to 6 . 1 .3. a . Release pressure from one tire/wheel assembly on each supply branch of the ATIS system of each i ncluded vehicle (power unit, trailer, dolly) under test. Reduce the pressure to a gauge reading of 95% of the SSP . b . If the re-inflate system has not activated for each assembly under test on or before a gauge pressure reading of 95% of SSP , discontinue any further testing . c . If the re -i nflate system has activated , record the pressure level of each deflated tire/wheel assembly at the point for which the system activates , and note whether the indicator panel message lamp (dash or external mount) has been act ivated , and remains activated , as long as the re-inflate system is active . d . At the poin t that the re-inflate system de-activates, record the gauge pressure of the re-inflated t ire/wheel assembly, and note whether the indicator panel message lamp has been de-activated . e . At the end of each test sequence : (1) validate that the system 's performance meets the thresho ld criteria specified in this document , and (2) validate that the information displayed on the indicator panel has communicated the system ' s response to the demand for inflation pressure . If the criteria has not been met , discontinue any further test ing .**ilo\\lil•~uhtlllollt"\\1** llhllt.tllnll I • \IC Ull 111111,1,\

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### SAE J2848-2 Issued JUN2011 Page 14 of 15 Phase II - The steps of Phase II should be conducted one tire/wheel assembly at a time . a . Release pressure from one tire/wheel assembly of each included vehicle (power unit , trailer, dolly) under test at a rate greater than the system 's ability to restore pressure . Keep the pressure release valve open for the duration of this test. b . If the re- inflate system has not activated for each assembly under test on or before a gauge pressure reading of 95% of SSP , discontinue any further testing . c . If the re-inflate system has activated , record the pressure level of each deflating tire/wheel assembly at the point for which the system activates, and note whether the indicator panel message lamp (dash or external mount) has been activated , and remains activated , as long as the re-inflate system is active . d . At the point that the re-inflate system has been isolated from the supply reservoir, record the gauge pressure of the tire/wheel assembly , record the gauge pressure level of the supply reservoir, and note whether the indicator panel message lamp remains on . e . Stop releasing pressure from the test assembly . Allow the system to restore the pressure to the specified level. f . At the end of each test sequence : (1) validate that the system ' s performance meets the threshold criteria specified for supply reservoir isolation, and (2) validate that the information displayed on the indicator panel has communicated the system 's status . If the criteria has not been met, discontinue any further testing . 6 . 1 .3 Test: Vehicle Rolling Test (for re-inflate systems which only function while rolling) Phase I a . Begin driving the vehicle . Achieve a speed of at least 25 mph . b . Release pressure from one tire/wheel assembly on one supply branch of the ATIS system of one of the included vehicles (power unit, trailer, dolly) under test. Reduce the pressure to a gauge reading of 95% of the SSP . c . If the re-inflate system has not activated for each assembly under test on or before a gauge pressure reading of 95% of SSP . discontinue any further testing. d . If the re- inflate system has activated , record the pressure level of the deflated tire/wheel assembly at the point for which the system activates . and note whether the indicator panel message lamp (dash or external mount) has been activated , and remains activated , as long as the re-inflate system is active . e . At the point that the re-inflate system de-activates . record the gauge pressure of the re-inflated tire/wheel assembly , and note whether the indicator panel message lamp has been de-activated . f . Repeat the steps of a . through e . for each tire/wheel assembly on each supply branch of the ATIS system of each included vehicle (power unit, trailer, dolly) under test. g . At the end of each test sequence : ( 1) validate that the system 's performance meets the threshold criteria specified in this document, and (2 ) validate that the information displayed on the indicator panel has communicated the system ' s response to the demand for inflation pressure . If the criteria has not been met, discontinue any further testing .

### SAE J2848-2 Issued JUN2011 Page 15 of 15 Phase II -The steps of Phase II should be conducted one tire/wheel assembly at a time . a . Begin driving the vehicle . Achieve a speed of at least 25 mph . b . Release pressure from one tire/wheel assembly of the vehicle (power unit , trailer, or dolly) under test at a rate greater th an the system ' s ability to restore pressure . Keep the pressure release valve open fo r the duration of this test. c . If the re-inflate system has not activated for the assembly under test on or before a gauge pressure reading of 95% of SSP , discontinue any further testing . d . If the re-inflate system has activated, record the pressure level of the deflating tire/wheel assembly at the point for which the system activates, and note whether the indicator panel message lamp (dash or external mount) has been activated, and remains activated, as long as the re-inflate system is active . e . At the point that the re-inflate system has been isolated from the supply reservoir, record the gauge pressure of the tire/wheel assembly , record th e gauge pressure level of the supply reservoir, and note whether the indicator panel message lamp remains on . f . Stop releasing pressure from the test assembly . Allow the system to restore the pressure to the specified level. g . At the end of each test sequence : (1) validate that the system 's performance meets the threshold criteria specified for supply reservoir isolation , and (2) validate that the information displayed on the indicator panel has communicated the system's status. If the criteria has not been met , discontinue any further testing. h . Repeat the steps of a . through f . for each tire/wheel assembly on each supply branch of the ATIS system of each included vehicle (power unit, trailer, dolly) under test. 7. NOTES 7 . 1 Marginallndica A change bar (I) located in the left margin is for the convenience of the user in locating areas where technical revisions , not editorial changes, have been made to the previous issue of this document. An ( R) symbol to the left of the document title indicates a complete revision of the document. including technical revisions . Change bars and ( R ) are not used in origi nal publications, nor in documents that contain editorial changes only .

PREPARED BY THE SAE TRUCK AND BUS TIRE PRESSURE MANAGEMENT SYSTEMS COMMITTEE OF THE SAE TRUCK AND BUS TOTAL VEHICLE STEERING COMMITTEE