Electronic control unit - Wikipedia Electronic control unit This article is about controls for motor vehicles. For other uses, see control unit ( disambiguation ). This article may be confusing or unclear to readers. In particular, the article lacks coherent structure ; especially in the lists, both bulleted and in paragraph form. Please help us clarify the article. There might be a discussion about this on the talk page. ( February 2015 ) An ECU from a Geo Storm. In automotive electronics, Electronic Control Unit ( ECU ) is any embedded system that controls one or more of the electrical system or subsystems in a transport vehicle. Types of ECU include Electronic / engine Control Module ( ECM ), Powertrain Control Module ( PCM ), Transmission Control Module ( TCM ), Brake Control Module ( BCM or EBCM ), Central Control Module ( CCM ), Central Timing Module ( CTM ), General Electronic Module ( GEM ), Body Control Module ( BCM ), Suspension Control Module ( SCM ), control unit, or control module. Taken together, these systems are sometimes referred to as the car 's computer ( Technically there is no single computer but multiple ones. ) Sometimes one assembly incorporates several of the individual control modules ( PCM is often both engine and transmission ). Some modern motor vehicles have up to 80 ECUs. Embedded software in ECUs continues to increase in line count, complexity, and sophistication. Managing the increasing complexity and number of ECUs in a vehicle has become a key challenge for original equipment manufacturers ( OEMs ). Examples of such ECUs include : Door control unit ( DCU ) Engine control unit ( ECU ) -- not to be confused with electronic control unit, the generic term for all these devices Electric Power Steering Control Unit ( PSCU ) -- Generally this will be integrated into the EPS powerpack. Human - machine interface ( HMI ) Powertrain control module ( PCM ) : Sometimes the functions of the Engine Control Unit and transmission control unit ( TCU ) are combined into a single unit called the Powertrain Control Module. Seat Control Unit Speed control unit ( SCU ) Telematic control unit ( TCU ) Transmission control unit ( TCU ) Brake Control Module ( BCM ; ABS or ESC ) Battery management system ( BMS ) Contents 1 Key elements of an ECU 2 Design and development 3 Testing and validation 4 Tuning 5 See also 6 References Key elements of an ECU Core Microcontroller Memory SRAM EEPROM Flash Inputs Supply Voltage Digital inputs Analog inputs Outputs Relay drivers H bridge drivers Injector drivers Logic outputs Communication links Housing Design and development The development of an ECU involves both hardware and software required to perform the functions expected from that particular module. Automotive ECU 's are being developed following the V - model. Recently the trend is to dedicate a significant amount of time and effort to develop safe modules by following standards like ISO 26262. It is rare that a module is developed fully from scratch. The design is generally iterative and improvements are made to both the hardware and software. The development of most ECU 's are carried out by Tier 1 suppliers based on specifications provided by the OEM. Testing and validation As part of the development cycle, manufacturers perform detailed FMEAs and other failure analyses to catch failure modes that can lead to unsafe conditions or driver annoyance. Extensive testing and validation activities are carried out as part of the Production part approval process to gain confidence of the hardware and software. On - board diagnostics or OBD help provide specific data related to which system or component failed or caused a failure during run time and help perform repairs. Tuning Some people may wish to modify their ECU so as to be able to add more functionality to it. Most ECU 's these days however come equipped with protection locks which prevent users from modifying the ECU. The protection locks are made in a way that, when circumvented, triggers DMCA liability. This in effect makes modifying the ECU by circumventing the protection illegal except if done under an exception to the DMCA. See also OpenECU CanBusHack iFixit References ^ Jump up to : National Instruments White Paper on Electronic Control Units Archived 2013 - 12 - 21 at the Wayback Machine. Jump up ^ Ebert, Christof ; Jones, Capers ( 2009 - 04 - 01 ). `` Embedded Software : Facts, Figures, and Future ''. IEEE Computer Society Press. Retrieved 2010 - 09 - 15. Jump up ^ Case, Lenny ( October 2011 ). `` Fast - tracking ECU development ''. Automotive Industries. Jump up ^ `` Circumventing ECU protection being illegal ''. Jump up ^ `` Federal Register ''. Automotive engine Part of the Automobile series Basic terminology Bore Compression ratio Crank Cylinder Dead centre Diesel engine Dry sump Engine balance Engine configuration Engine displacement Engine knocking Firing order Hydrolock Petrol engine Power band Redline Spark - ignition engine Stroke Stroke ratio Wet sump Main components Connecting rod Crankcase Crankpin Crankshaft Crossplane Cylinder bank Cylinder block Cylinder head ( crossflow, reverse - flow ) Flywheel Head gasket Hypereutectic piston Main bearing Piston Piston ring Starter ring gear Sump Valvetrain Cam Cam follower Camshaft Desmodromic valve Hydraulic tappet Multi-valve Overhead camshaft Overhead valve Pneumatic valve springs Poppet valve Pushrod Rocker arm Sleeve valve Tappet Timing belt Timing mark Valve float Variable valve timing Aspiration Air filter Blowoff valve Boost controller Butterfly valve Centrifugal - type supercharger Cold air intake Dump valve Electronic throttle control Forced induction Inlet manifold Intake Intercooler Manifold vacuum Naturally aspirated engine Ram - air intake Scroll - type supercharger Short ram air intake Supercharger Throttle Throttle body Turbocharger Twin - turbo Variable - geometry turbocharger Variable - length intake manifold Warm air intake Fuel system Carburetor Common rail Direct injection Fuel filter Fuel injection Fuel pump Fuel tank Gasoline direct injection Indirect injection Injection pump Lean - burn Stratified charge engine Turbo fuel stratified injection Unit injector Ignition Contact breaker Magneto Distributor Electrical ballast High tension leads Ignition coil Spark plug Wasted spark Electrics and engine management Air -- fuel ratio meter Alternator Automatic Performance Control Car battery ( lead -- acid battery ) Crankshaft position sensor Dynamo Drive by wire Electronic control unit Engine control unit Engine coolant temperature sensor Glow plug Idle air control actuator MAP sensor Mass flow sensor Oxygen sensor Starter motor Throttle position sensor Exhaust system Automobile emissions control Catalytic converter Diesel particulate filter Exhaust manifold Glasspack Muffler Engine cooling Air cooling Antifreeze ( ethylene glycol ) Core plug Electric fan Fan belt Radiator Thermostat Water cooling Viscous fan ( fan clutch ) Other components Balance shaft Block heater Combustion chamber Cylinder head porting Gasket Motor oil Oil filter Oil pump Oil sludge PCV valve Seal Synthetic oil Underdrive pulleys Portal Retrieved from `` https://en.wikipedia.org/w/index.php?title=Electronic_control_unit&oldid=836493931 '' Categories : Embedded systems Power control Engine technology Fuel injection systems Engine control systems Engine components Onboard computers Auto parts Automation Hidden categories : Webarchive template wayback links Wikipedia articles needing clarification from February 2015 All Wikipedia articles needing clarification Talk Contents About Wikipedia Български Català Čeština Deutsch Español Français Bahasa Indonesia Italiano Bahasa Melayu Nederlands 日本 語 Português Română Русский Slovenčina Svenska Українська 8 more Edit links This page was last edited on 15 April 2018, at 03 : 33. 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Question: how many electronic control units in a car
Answer: up to 80