Yellow check Engine Light

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asad7860

Active Member
Joined
Apr 29, 2008
Messages
117
Location
UK
Car
E55 W211
Hi all

Was driving home last night a yellow check engine light came up on the dashboard - (the light looks like an engine).

Car is fine. Still very responsive. Light still on today.

Any ideas?

Cheers

Asad - C32 AMG 2002.
 
Could be a whole host of things to cause this....your best bet is to get a diagnostic check done which will list the fault codes and you can then take things from there.
 
Might be an idea not to do too many miles until you find out whether the fault is minor or serious?
 
Intercooler pump a good suggestion, but you would notice a lack of power I think. More likely is aux air pump relay. light does not clear on switch off suggests emission related to me, but no change in 'feel' means not in limp, so probably not desperately serious yet. Code reading is next step, as already said by others.
 
When any of a broad host of sensors returns a value out of its allowed range, the Check Engine lamp will light up and the sensor's ID will be stored in the engine management computer, to be drawn back out through the OBD (On-Board Diagnostics) port.
Without having the code to ID the sensor, guesses are of little value. Google OBD, and brace for the flood. If this is about your 2002, it will still be "OBD-I", Kenobe.

>>Correct my mistake, OBD II started in 1995, and was mandated in 1996. I've had troubles with model years since we've begun another century without really finishing that last one.
 
Last edited:
Sure. Could be a temperature sensor, an EGR solenoid, the manifold air pressure sensor, the idle speed control solenoid, or any of these 800 or so:

http://www.obd-codes.com/trouble_codes/

That's why the system stores the codes. So your mechanic doesn't have to make 799 guesses before hitting the right one.
 

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