Check engine light.
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Joined: Sep 2002
Posts: 58
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From: San Diego, CA
1992 Mecedes-Benz 400E
Check engine light.
Does anyone know the proper way to manually find and reset the car computer? I have tried the method where the key has to be turned to the "on" position and press the button for 3 seconds until the first error code flashes. Then press the button again for 3 seconds until the second code flashes and so on until it repeats the first code. To erase the codes I waited 2 seconds and then held the button down for 6 seconds. I did this for every code but it does not erase the codes. The check engine light comes off but the codes are still in the computer and the light soon comes on again, in a week or two. If anyone knows a different method or different times lengths to hold the button down it would be really helpful. Also if anyone know what the codes mean for the V-8
Newbie
Joined: Jan 2006
Posts: 3
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From: Belmont, CA
1995 E420, 1976 450SL, 1996 C280
On the old style OBD1 system the check engine light is reset by disconnecting the battery for 10 seconds. Be carfull not to go over 30 seconds or you will have to reset your radio is you still have the OEM Becker.
Newbie
Joined: Jan 2006
Posts: 3
Likes: 0
From: Belmont, CA
1995 E420, 1976 450SL, 1996 C280
Just a quick note.
All OBD systems run periodical diagnostic test (some say every 45 minutes of continues driving). As an example the system will send a signal to the three way vacuum valve to activate the EGR valve. It looks for an RPM drop to confirm it's operation. If it doesn’t get an rpm drop signal it will kick out a fault code the next time you start the car. This could be caused by a faulty EGR valve or a cracked vacuum hose. All it know is that the system is not functioning. You can reset the check engine light but it will kick out the code after it has run another diagnostic test and the car is restarted.
All OBD systems run periodical diagnostic test (some say every 45 minutes of continues driving). As an example the system will send a signal to the three way vacuum valve to activate the EGR valve. It looks for an RPM drop to confirm it's operation. If it doesn’t get an rpm drop signal it will kick out a fault code the next time you start the car. This could be caused by a faulty EGR valve or a cracked vacuum hose. All it know is that the system is not functioning. You can reset the check engine light but it will kick out the code after it has run another diagnostic test and the car is restarted.
Last edited by Riceman; Jan 7, 2006 at 05:09 PM.
