Why automotive computers need reprogramming


If you wonder why there are so many “reflashes” (reprogramming) of vehicle computers, i.e. why the software needs so much rewriting, here’s an example of what the software writers might miss:

Some 2007-08 Dodge Calibers, Jeep Compasses and Patriots and 2008-09 Dodge Caliber SRT-4s have been illuminating their MILs (Check Engine Lights) this past winter, and logging trouble code P2610 (Powertrain Computer Internal Engine-Off Timer Performance).

Huh? That’s a timer strategy that compares ambient temperature with the rate of engine-off cool down, and in this case, the computer did not see the rate of cool down it was expecting. Because engine emissions on startup are so critical, the computers keep track of lots of things, even when the engine is off (as you know, they have keep-alive memory fed by the battery). The Chrysler dealers who took good vehicle histories, and who carefully questioned the car owners about the vehicle’s operating conditions, quickly determined that the MIL came on after the engine block heater was used on a cold day/night.

It turns out that the software was never written to cover the possibility that an engine block heater would be used, keeping the engine warm in cold weather. Someone apparently forgot to list that scenario with all the subjects that the software engineer had to cover when he wrote the P2610 trouble code setting parameters. A reflash just issued by Chrysler compensates for the omission.


When having your mobile A/C system professionally serviced, insist on proper repair procedures and quality replacement parts. Insist on recovery and recycling so that refrigerant can be reused and not released into the atmosphere.

If you’re a service professional and not a MACS member yet, you should be, click here for more information.

You can E-mail us at macsworldwide@macsw.org or visit http://bit.ly/cf7az8 to find a Mobile Air Conditioning Society member repair shop in your area. Visit http://bit.ly/9FxwTh to find out more about your car’s mobile A/C and engine cooling system.

The 32nd annual Mobile Air Conditioning Society (MACS) Worldwide Convention and Trade Show will take place January 18-20, 2012 at the Rio All Suite Hotel and Casino in Las Vegas, NV.


About macsworldwide

Mobile Air Conditioning Society (MACS) Worldwide Founded in 1981, MACS is the leading non-profit trade association for the mobile air conditioning, heating and engine cooling system segment of the automotive aftermarket. Since 1991, MACS has assisted more than 600,000 technicians to comply with the 1990 U.S. EPA Clean Air Act requirements for certification in refrigerant recovery and recycling to protect the environment. The Mobile Air Conditioning Society (MACS) Worldwide’s mission is clear and focused--as the recognized global authority on mobile air conditioning and heat transfer industry issues. www.macsw.org
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One Response to Why automotive computers need reprogramming

  1. Frank Alvis says:

    Thank u. Very informative we do some serious engine modification and install turbos and aftermarket superchargers but we need people like u guys to help us in the auto Computers modifications. Thank u. Frank Alvis. Alvis Racing Motorsports

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