1996 Mercedes-Benz C220 Q&A
1996 Mercedes-Benz C220 Question: Emmissions test fails
The states emissions test fails due to several not readies on the diagnostic test. I was told to drive the car and come back for a re-test, this has been done several times with the same failed results. The Mercedes dealer said their is no trouble with my car. Is there an on board control unit that I can try to replace or should I take the car back to the dealer for a recheck? - johnbal
I just went through this with another 1996 Mercedes. I am a Calif. Smog Tech that works at a Gold Shield Station ( means that the State sends us cars that other shops have struck out on ). The Mercedes had several problems. The dealer did, in SF did not even know how to work on the problem The car was broken/malfunctioning for 4 years. What I found is that there is a separate computer that only does the OBD-II monitors. It is called the Diagnostic Monitor or module.The Dealer does not even know where it is in the car because I called several, all over the US, they think it is built in to the main Engine Computer. IT IS NOT!!. The computer is usually in the Engine Fuse Compartment by the round Mercedes Diagnostic Connector. It may even say CARB on it. California Air Resources Board which mandated its existence. The Factory did not even know about it. I had to get it from a special German parts person and it was a used one to boot. However, this definitely fixed the problem. Let me know about this because there are several things to check before putting in this computer, like do you automatic door locks work OK? I will explain why this is so important later. - dandd
I just drain all the gas go to Home Depot and get 2 gallons of alcohol and put it in the tank and it passes every time !!! - Visitor
Was the issue fixed. I have the same problem with my 1996 Mercedes Benz S 500. - MICHEZO
I came across an earlier post regarding this same problem i am located in socal can someone provide details on this "chip" for the monitors to pass- the smog passes but the monitors fail they keep ...