Question about 1991 Mercedes-Benz Mercedes Benz 500 Class

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ECU I own a 500SE '91 W126. How do i reset the ECU?

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ECU doesnt get reset its fixed. If your trying to clear a CEL you need a reader. You can make one by going to and looking up homemade reader. The reader can clear codes also.

Posted on Jul 09, 2009


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Cant find the fuel injection relay on 91 Geo storm

the 91 cars , typically have 3 fuses that must be good.
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I have a 91 talon tsi awd. the kid i got it off did some stupid thing with the stock wiring harness. now the car has a problem starting but after start up the car is a beast. i feel like the car isn't...

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A common "trick" with the wiring is to change the MAF sensor (on the air filter can) around to get more fuel at high boost. Pull off the 8 pin connector and check for bent pins. Check for 5V (NOT +12v) on one of the pins, as this is the MAF sensor supply voltage.

Other issues are the coolant temp sensor (2 pin sensor with black? connector on the themostat housing) connection.

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Check all the vacuum hoses for cracks and leaks. Check the hoses for the intercooler and up to the throttle body.

Have a look at for more information.

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There aren't many people dealing with the W126 these days. The best place is ebay. Otherwise you could end up paying a small fortune at a specialist dismantler. But before you leap, look up the parts for the E class W124, many items were the same. Good luck

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