Modern Car 'ODBII' Interface, a MUST have!! - Page 1
Forum section: electronics / general

author: GlennSprigg
author_rank: Super Contributor
timestamp: June 30, 2019, 11:39:43 am
content: I'm not sure if this has been discussed before, (see below), but vehicle accessory companies are NOT justallowing us to plug-in an 'ODBII' device to monitor the engine, & diagnose faults, but to RESET the computer!See the following as an example, for how cheap it is to purchase now, to Bluetooth link to a SmartPhone....https://www.ebay.com/itm/ELM327-Car-Auto-Wireless-Bluetooth-V2-1-ODB2-ODB-II-Diagnostic-Scan-Scanner-Tool/163297825538?epid=17011311410&hash=item26054f1302:g:m7wAAOSwNlJc9OFbTHIS IS WHAT I HATE THOUGH, ABOUT MOST NEW CAR MANUFACTURERS !!! Seeing a 'Warning' light on yourdashboard, (not that there is a 'fault' per-se), but that you are due for a manufacturers 'Service'.... Ok......?However if you ignore it, then 'strangely' your engine suddenly starts 'running rough' etc etc....I'm sorry, but this is so common, that a whole HERD of company engineers could not convince me that this isnot DELIBERATELY programmed into the system, to FORCE people to pay for 'specialized' Servicing, by 'them'It's equally 'amazing', how via such an above 'device', you can reset the System, and WOW!!, the enginenow purrs like a kitten again?Idon'tso much complain about the initial 'notification', as not allpeople are car-savvy, or 'remember' about Services etc., however I FU**ING well DO object to my vehicle beingDELIBERATELY CRIPPLED until I 'succumb' to their stand-over tactics !!!Just plug this Baby in... be amazed at all the info it can give you... check real faults... & reset the bastard !!

author: Rerouter
author_rank: Super Contributor
timestamp: June 30, 2019, 11:52:29 am
content: This really comes off a bit scammy,I would say its always best to actually read the reported fault code and write it down somewhere, as it can indicate a loose plug connection or failing sensor,These devices do not perform a full reset of the ECU, rather they clear the cached data such as the fuel trims, and other learned performance trims, it then takes between 20 minutes to an hour of driving at decent speeds to relearn these valuesMost ECU's also have a non volitile space where they store the error log history, when each error was last cleared, information from the past X service histories including the type and how many days you where late or early, and general driving performance metrics like top RPM, top tourqe and top speed in a few bins going back about 6 months, these are there to clue in any servicing people that are chasing an intermittent fault. some even have wear estimations of a number of components in the vehicle,To my knowledge I have not come across any vehicles that lock you into a OEM only servicing plan, (well apart from some super rich sports cars that only pops the bonnet via talking through the radio helpline)My best recommendation would be use the cheap OBD scanner to read the code, look it up as it will be a public code, and see if its something you can personally easily investigate, and if your going to keep blindly resetting it, just know check engine light means you should... check on the engine.

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: June 30, 2019, 11:58:35 am
content: This isn't actually new, OBD2 has bee around for quite some years and so have diagnostic devices. There were CAN based car diagnostics years before OBD2 btw. (and K-Line before CAN) and there are still non-OBD2 CAN based protocols which allow even more than OBD2 depending on the manufacturer.And yes, you can reset faults. But uncritical faults will be usually reset automatically after so and so many driving cycles without faults. Safety related faults aren't automatically reset to make sure they are noticed and handled correctly. If they are just reset through CAN without fixing the underlying issue, they will just appear again after some time."Running rough" could be some kind of "limp home mode". I.e. if the crank sensor is defective, you can still use the camshaft sensor on most cars but as it's less accurate, they won't allow you to use high engine speeds and things like that. This is the same for lots of sensors and actuators. So there is no conspiracy.

author: GlennSprigg
author_rank: Super Contributor
timestamp: June 30, 2019, 12:14:02 pm
content: I understand about using such terms as "Running Rough", and I also understand about certain vehicles"Limp Home" modes...... For example, some vehicles, especially V8's, will systematically 'shut-down' cylindersif you are 'Over-Temp', so as not to be stuck in a remote environment/place. Etc. And I know about intermittentpulses from the likes of 'Crank-Angle' sensors... etc...However, I am talking about numerous people I know that SUDDENLY have certain 'issues', shortly afterwarnings about 'Servicing'. WAY to many to be ignored, or blamed on 'real' specific faults....

author: Rerouter
author_rank: Super Contributor
timestamp: June 30, 2019, 12:20:21 pm
content: So to be clear, using one of these to read off the DTC returns no active DTCs? including if you checked just after the warning appears? just to make sure I am understanding your story,I would take a guess its probably a Mercedes / Porsche / BMW based on the culture of servicing first.

author: Dacke
author_rank: Regular Contributor
timestamp: June 30, 2019, 01:05:57 pm
content: Quote from: GlennSprigg on June 30, 2019, 12:14:02 pmWell it can certainly work that way though? You could have a DTC trigger a service engine light, and it's very plausible that the car could run like crap depending on what the problem is... Examples would be a failed EVAP purge solenoid or general EVAP system failure, a faulty mass airflow sensor, a faulty crank position or cam position sensor, faulty EGR valve, etc. It can be a long list... OBD-II has been around a long time and for as many cars as I've worked on over the years, I certainly haven't noticed any type of trend or conspiracy.

author: Gyro
author_rank: Super Contributor
timestamp: June 30, 2019, 01:07:25 pm
content: As 0xdeadbeef (and Dacke) say, OBDII isn't new, in fact it has been compulsory on cars in Europe for about two decades, diesel vehicles were given a few years extra grace as I remember. Even the location of the OBDII connector is standardised to be within a certain distance of centre line in the passenger compartment (no manufacturer specific connector in the engine compartment). Maybe the US legislation has lagged on this, hence the OP's apparent surprise.OBDII lays down a fixed set of fault codes (DTCs) which must be common to all vehicles, including engine, transmission, abs etc. together with the ability to check the vehicle VIN and reset fault codes (getting rid of the warning light). These are a subset of all the codes that a specific vehicle is capable of presenting though.What still isn't common and accessible with cheap scanners though, is the ability to change settings, parameters (other than clearing faults) on the individual subsystems, enabling / disabling optional features etc. For these you still need manufacturer specific software such as Opcom which has versions for different manufacturers eg. Vauxcom for some GM models. Hacked versions sometimes come with cheap OBDII dongles, but without this sort of specific software you are very limited in what you can accomplish.It is entirely possible to get a warning light, which doesn't show up any generic DTCs on a cheap reader, but which can be cleared (fault light extinguished) using its 'Reset' command. Of course if the fault is permanent or re-occurs, then the light will come on again.If a non-DTC fault is causing some kind of limp mode then it may result in poor running until reset by the scanner, but without identifying and fixing the fault, it will probably reoccur. If you just "RESET the computer", actually just clearing the fault codes, then you're just deleting diagnostic information that would speed up fault location and repair.I've never seen a case of the fault light being used as a 'service conspiracy light', that just sounds like uninformed spam. There is normally a separate indication of when a service is due, and a manual sequence, often involving ignition key and trip reset button in a sequence to reset it.https://www.obd-codes.com/https://en.wikipedia.org/wiki/On-board_diagnostics#OBD-II

author: SparkyFX
author_rank: Frequent Contributor
timestamp: June 30, 2019, 01:56:17 pm
content: I understand the frustration, with older cars you just drove until it broke and then had to fix everything the defect took with it. Emission regulations however demand self diagnosis capabilities in the car, especially for the O2 sensors, so that when a suboptimal air/fuel mix is reported you get an indication to fix the issue. You can do that before other parts take damage, often before other symptoms even show up.These are closed loop governors, the controller will increase or decrease fuel mass depending on the sensor reporting a too lean or too rich air/fuel mix (based on remaining oxygen in the exhaust gas). Therefore a problem there can make the car driving rough, have rpm stability issues in idle before the self diagnosis switches in limp-home mode, the engine then practically ignores the sensor and avoids overheating by using default values and decreasing power output drastically, but always with the malfunction indicator light.The thing is, even with older cars sooner or later certain defects have consequences, if e.g. the tubing on the intake side is cracked and pulls air in, the mix is too lean and therefore burns hotter, then taking a toll on gaskets, flatness of mating surfaces, valves and piston rings. At first you don´t feel much of it while driving, but it gets worse. If an injector is worn out (the fuel flow and valve action makes them oversize after some years of use) or if the fuel pressure is affected (pressure regulator worn out), you have too rich of a mix and get a lot of soot, clogging valves, oil channels (per crankcase ventilation), exhaust. Turbo engines then have a little different symptoms, it always depends.A helpful way to approach the problem is to check during operation: is the engine rpm stable in idle and does the engine have full power available, is partial load while driving ok? That gives you 3 conditions in which to take data and to work from.You can exclude O2 sensors themselves as the cause of an issue by cross-checking other values, like mass air flow and commanded fuel mass, but that takes some experience, trained ears and comparison values from cars that are considered OK.Modern cars do have more parts that can fail, and more complex intake air systems that can mess things up and be harder to diagnose, butby definition any defect will have a consequence and show symptoms in a system, sooner or later.The indicator is often just faster.What these self diagnosis capabilities are absolutely horrible with, are things outside of its spectrum, like varying fuel quality, engine oil quality, service fails (like clogged air filters), most people tend to focus on the indicator instead of the cause, which makes things worse and ridiculous issues take them forever to find.Btw. the controller not only reports trouble codes, it also stores if they were cleared and tells if the self diagnostics even had a chance to run in the mean time. Therefore technical inspection over here sees if someone just cleared codes before showing up and then lets the car run for some time until all of these flags are set. For everyone else they just check if all flags are set, therefore self diagnosis works, emission inspection is therefore passed. Which is why with the diesel scandal they had to revert to measuring exhaust gas.

author: sokoloff
author_rank: Super Contributor
timestamp: June 30, 2019, 02:30:01 pm
content: Quote from: Gyro on June 30, 2019, 01:07:25 pmRequired in the US since model year 1996 for passenger cars and light trucks.

author: Brutte
author_rank: Frequent Contributor
timestamp: June 30, 2019, 03:06:45 pm
content: Some fault logs can be reset only by the manufacturer of the part, some only by the approved service and some by anyone that has the OBD reader. On top of that here are errors that will just disappear when the fault disappears or when you power-cycle.Of course you might clear limp mode by resetting/power-cycle of an ECU if that is associated with the last type of fault. However, then you might loose the error codes.If that is intermittent falut, you'd better fix the problem and not reset it.

author: JPortici
author_rank: Super Contributor
timestamp: June 30, 2019, 08:13:37 pm
content: two thoughts:- My Skoda Octavia 5E will show the idiot light if the wiper fluid is low(altough for more serious issues will have different lights and messages, such pilot light flashing for engine issues)- I had to work on an old subaru impreza, that used an archaic method to show/clear faults. Put a jumper between two specific pins in the diagnostic connector, then some LEDs will flash in a specific pattern, which will tell you the fault. To clear faults put the jumper between two other pins and drive for about 10km. Give me OBD any dayI'm so glad that we have OBD2 with a standardized connector and a standardized protocol for most things... I shiver every time we get to work on cars with the old proprietary interfaces.Then there are vendor specific diagnostic tools (the "REAL" ones) that use UDS as the protocol to do a lot of fantastic things. All in all i'm happy i got a skoda because i can use the marvellous piece of software that goes by the name "VCDS".

author: GlennSprigg
author_rank: Super Contributor
timestamp: July 02, 2019, 10:56:20 am
content: Hmmm... To be honest, (I'm an Aussie, (OP)) and I should have said that I was 'really' referencing ourlater/latest model 'Holdens'. I understand, again, if there was any 'real' faults, intermittent or otherwise,that this 'may' trigger some sort of 'Requires Service' notification. In addition to the 'fault' msg.I'm not talking about 'Willy-Nilly' Resetting, irregardless of whether there were any 'real' faults, althoughI will say that I was being 'tongue-in-cheek' in my original last sentence !!INTERMITTENT faults are the Bane of any elect/tech in the best of times, and the ability to Diagnose suchphenomena these days, is a fantastic ability of today's computerized systems, and is a God-Send !!I still maintain though, that I've witnessed many peoples apparent 'faults', not long after servicing msgs.And that 'diagnosis' indicates NO real faults, intermittent or otherwise... (Including a pro-mechanic friendusing his very expensive pro-diagnostics system, not just the above-mentioned cheap tool).These 'Faults' have NOT shown up in any system log! They just cause running issues ONLY after such'servicing' notifications show up, on their OWN. And NO real faults, other than computer generated.VehicleManufacturers/Servicing Depts, make their money from 'After Sale Services/Parts'........My 'Missus' has a late model Hyundai Grandeur. A headlight 'globe' was blown. Ok, it was a Special'HID' (High Intensity Discharge) 'Globe'... After wandering through the ridiculously opulent local 'Service-Centre', walking past executives in Armani suits with attache cases, we found their 'Inner-Sanctum',resplendent with glamour queens at a 'reception' counter, sipping Lattes'... We found out that the neededreplacement would be ordered in, and will cost $350 !! After choking/laughing much to their distaste...I went on-line, and received TWO of them for $50 total. I'm not sure If I know enough 'expletives' todescribe my 'feelings' about today's 'Services'

author: Halcyon
author_rank: Unknown
timestamp: July 02, 2019, 11:03:26 am
content: ODB-II and it's capabilities have been known for a long time. I wouldn't be buying one of those cheap Chinese units though. They are next to useless.About 10 years ago, I bought a Wi-Fi tool to interface into my car. That being said, it doesn't give you unrestricted access to the ECU and other systems.If you wait until the "Check Engine" light comes on before you service your car, you're a moron.Service your caron-time(that means at the kilometre or time interval, whichever comes first), check fluids and air pressures regularly and contact your dealer/manufacturer for software updates/service campaigns.

author: Rerouter
author_rank: Super Contributor
timestamp: July 02, 2019, 11:19:05 am
content: Holden is a special snowflake in all this mess, they keep most of there diagnostic info behind there special "Tech 2" programmer, which has different $XXXX and $XXXXX options for each rebrand holden does, e.g. Holden Astra = Opel Astra, Holden Colorado = Cheverolet Colorado, This has been going on for decades.E.g. the old VY/ VZ commodores had a factory defect that jammed the fuel sensor occasionally so it would not fall down towards empty (car runs out of fuel but gauge reads 1/4) well turns out there where only 2-3 places you could go to in NSW to get the new (used the same part number on the revised part, which had a reversed calibration) fuel sensor learned into the car, because it required this "Tech2" programmer and someone well enough versed in its madness to use it.Attached is an example of everything that could be programmed in the cluster via the Tech2 part, I now have my own ways to reprogram essentially all of it, your one is probably not too dissimilar, And it could just be a badly set servicing interval, however I cannot speak to the running rough when it comes on part.

author: eugenenine
author_rank: Frequent Contributor
timestamp: July 02, 2019, 01:12:10 pm
content: My research found that OBD-II has standardized codes for engine and transmission but other things like ABS, SBA, infotainment, etc are not standardized and won't be read by typical consumer based readers.I'm wondering if the OBD-II to buetooth/wifi will at least read those non-standard codes, the handheld reader I bought from NAPA doesn't.

author: SparkyFX
author_rank: Frequent Contributor
timestamp: July 02, 2019, 04:48:37 pm
content: Quote from: GlennSprigg on July 02, 2019, 10:56:20 amWhich model and which fault message?OBDII covers only emission relevant faults, originating from California ARB. The same services can be used with some manufacturer proprietary information on an extended instruction set or on different busses, but thats all trade secret.Some OBDII tools do show the manufacturer specific trouble codes additional to the standardized ones, some don´t. You can get quite some information by googling them and set the context of the manufacturer, so any code is better than none. The rule of thumb is that with a warning indicator a trouble code should be stored and stay saved in the memory for a few ignition cycles, so that the aftersales service has a chance to see what was going on.Quote from: Rerouter on July 02, 2019, 11:19:05 amThe Tech 2 is outdated since 2008, it´s now GDS2 (Laptop with a "VCI"), which does not allow that extensive reprogramming as it was the case. Basically the Service Programming System does require an online connection and only sends a predefined configuration. Changes require an ordering process to adapt the data for the individual vehicle - no clue if this is available too in oceania.

author: GlennSprigg
author_rank: Super Contributor
timestamp: July 04, 2019, 11:22:01 am
content: Quote from: Halcyon on July 02, 2019, 11:03:26 amI never understand why some people come down so 'heavy', even after explaining twice more that I'mNOT talking about 'Ignoring' possible real faults, or even proper Servicing.....(sigh...)I, and my friends, have/hadalwaysbeen fully equipped & capable to do our OWN 'Servicing' & Repairs,for every car(s) we have ever owned... With the exception of myself for the last year, due to massive medicalissues I now suffer from & the time I have left. And I can assure you 'we' are NOTmorons......Fault-Codes are an excellent guide, even for the cheapest Modules, but is not all that 'we' rely on.I even stated that 1 friend IS also a Professional Mechanic working for a major Professional Servicing company,who relies on/uses very expensive high-tech computer analyzers, geared towards all the latest model vehicles.'Holden' has been 'renowned' in recent years to NOT conform to industry 'standards' in regards to 'Coding'.He confirms that NO actual/real 'faults' (intermittent or otherwise) are present at times, for 'Service' requests !!Please don't insult our intelligence/knowledge about any level of 'servicing' ever required. Again, we just don'twant to be 'bullied' by some Big-Guns in the industry, telling us who to use.... Believe it or not, it happens !!