Powertrain control module: Difference between revisions

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other abbreviations / names for pcm
m clean up using AWB (10003)
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{{howto|date=May 2012}}
{{merge|Engine control unit|date=October 2013}}
[[File:An_ECM_from_a_1996_Chevrolet_BerettaAn ECM from a 1996 Chevrolet Beretta-_2013 2013-10-24_2324 23-13.jpg|thumbnail|An ECU from a 1996 [[Chevrolet Beretta]].]]
 
A '''powertrain control module''', abbreviated '''PCM''', is an [[automotive industry|automotive]] component, an [[electronic control unit]] (ECU), used on [[motor vehicle]]s. It is generally a combined control unit, consisting of the [[engine control unit]] (ECU) and the [[transmission control unit]]. On some cars, such as many Chryslers, there are multiple computers: the PCM, the Transmission Control Unit, and the Body Control Module, for a total of three separate computers as an example. These automotive computers are generally very reliable. The PCM commonly controls more than 100 factors in a car or truck. There are many hundreds of error codes that can occur, which indicates that some subsection of the car is experiencing a problem. When one of these errors occurs, usually it will turn on the "check engine" light on the dashboard. The PCM is one of potentially several onboard computers, or essentially the "brain" of the engine control system. When the "brain" does not function correctly, neither will the engine or anything else that the microprocessor controls, which may include the charging system, transmission, various emission controls and communications with other onboard control modules. The PCM should be replaced only when it is diagnosed to be defective.
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*P0606....ECM/PCM Processor
*P0607....Control Module Performance
*P0608....Control Module VSS Output
 
If you see any of these codes when diagnosing the vehicle with a code reader or scan tool, it may mean the PCM has failed and must be replaced. There can be other reasons for these codes as well, so the presence of any of these codes does not definitively mean the PCM needs to be replaced. Additional diagnostic tests will usually be necessary to confirm the problem is really the powertrain control module and NOT something else. Refer to the OEM diagnostic charts for what these tests are. Usually it involves checking certain inputs to the PCM to see if it outputs the correct response. No response or an incorrect response usually means the PCM is defective and needs to be replaced. Professional Automotive Technicians use extremely expensive equipment ($4,000 to $8,000) to do the extensive and complicated diagnostics that are required before eliminating all other possibilities, to be able to arrive at a firm conclusion that the PCM has failed.
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* PCM: Powertrain control module (Ford/GM)
* ECM: Engine control module
* Injection control unit (Peugeot,<ref>http://www.obdtester.com/psacom-eculist/peugeot/607_1999_2004_van</ref>, Citroen, Fiat, Alfa, Lancia)
* DME/DDE: Digital Motor Electronics / Digital Diesel Electronics (BMW,<ref>http://obdtester.com/bimcom-eculist/bmw/5/2008_e60_e61</ref>, Mini)
 
==Bibliography==
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==References==
{{Reflist}}
 
 
[[Category:Embedded systems]]