Car passes smog but "check engine" light is still on?
Super Member
Joined: Dec 2002
Posts: 882
Likes: 2
From: Sherman Oaks
2004 C240, 2015 GL350 Bluetec
get the diagnostic codes read, that should point in the direction of the culprit. I had check engine light on but car ran perfect. turned out to be a bad hose on the smog pump that cleared it. you could reset the Check engine light, go get your smog and hopefully it wont come back on right away. I could reset mine before I got the hose fixed and it would stay off for days to weeks.
AshMan
AshMan
Super Member
Joined: Dec 2002
Posts: 882
Likes: 2
From: Sherman Oaks
2004 C240, 2015 GL350 Bluetec
by the battery there is a diagnostic port. you can turn the ignition on and hold the little button down for about 30 seconds then turn off the ignitiona nd the the Check engine light should be reset.
If it generates a code, you can pus the button down ont he diag connector for a couple of seconds then release and it should flash. and you can count the flashes. I forget the site where you can decipher the flashes.
Take it to a good mb mechanic, they should be able to read the codes.
AshMan
If it generates a code, you can pus the button down ont he diag connector for a couple of seconds then release and it should flash. and you can count the flashes. I forget the site where you can decipher the flashes.
Take it to a good mb mechanic, they should be able to read the codes.
AshMan
Thread Starter
Super Member
Joined: Nov 2002
Posts: 977
Likes: 0
From: San Jose
300TE / 300E / 300CE
Originally Posted by ashman
by the battery there is a diagnostic port. you can turn the ignition on and hold the little button down for about 30 seconds then turn off the ignitiona nd the the Check engine light should be reset.
If it generates a code, you can pus the button down ont he diag connector for a couple of seconds then release and it should flash. and you can count the flashes. I forget the site where you can decipher the flashes.
Take it to a good mb mechanic, they should be able to read the codes.
AshMan
If it generates a code, you can pus the button down ont he diag connector for a couple of seconds then release and it should flash. and you can count the flashes. I forget the site where you can decipher the flashes.
Take it to a good mb mechanic, they should be able to read the codes.
AshMan
I don't see any flashes. It just lights when I depress it while the ignition is on. Am I doing something wrong? I'll seek professional help but before then I can't get my smog, registration, or insurance!
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Super Member
Joined: Dec 2002
Posts: 882
Likes: 2
From: Sherman Oaks
2004 C240, 2015 GL350 Bluetec
I usually turn the ignition on and then very quickly run to the led and push the little button then release it then push it and hold it for 30 seconds then turn off the ignition and it resets the Check engine light.
I would assume that it should work for your car.
I think you have to push the button within a certain amount of time of turning ont he ignition.
AshMan
I would assume that it should work for your car.
I think you have to push the button within a certain amount of time of turning ont he ignition.
AshMan
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Thread Starter
Super Member
Joined: Nov 2002
Posts: 977
Likes: 0
From: San Jose
300TE / 300E / 300CE
I was able to get it to flash three times ONCE! But all attempts at getting to the button to hold down still did not turn off the Check Engine light. I may have to have my wife turn the key so I can press the button faster...
I may have to have my wife turn the key so I can press the button faster...
