Bad ECU

Recently had time to check the codes on my 03. It was a mass air code that came up. I replaced the air mass sensor and drove for about 2 miles before the code came up again. The mercedes tech checked the wiring running from the ECU to the air mass sensor and found everything to be in order. EGR was functioning as well. What was amiss is the fact that the voltage would not increase from idle(.09) when raising the rpm. I was told that it should top out at 3 volts during acceleration. Mercedes thinks its a bad computer. Any Ideas? I know with other cars the ECU is repairable, are these? thanks Marc

The mass air flow sensor gets plausibility readings from several other sensors such as the air intake temp sensor. If any sensor is sending an implausible signal, it will appear the mass air flow sensor is bad. It gets replaced and then the tech assumes the ECU is bad when it is most likely not. Start with checking the air intake temp sensor. It may be out of spec. Hope this helps.

Thank you, John
Sprinter Store
http://sprinterstore.com/
A division of Upscale Automotive, Inc.
19460 SW 89th Ave.
Tualatin, OR 97062
503-692-0846