Check Engine Light M103
 

Hi,

I searched on these keywords [check engine light m103] (both with and without the ‘m103’) but to my surprise did not find anything useful. So here goes:

What does the Check Engine Light mean in a perfectly running M103?

My ‘92 300TE, M103 with 111k miles today has the Check Engine light on. This is of course perfect timing as I had a surgery last Thu and cannot do any involved repair myself!! Car runs and feels absolutely fine (although first cold start will be in the morning.) Is this a DYI or do I need to get the fault codes?

Thanks!

It means a fault code was tripped. The CE light only deals with smog / emissions related equipment.

You need to have the codes checked. EGR valve? O2 sensor?

Went to dealer. Coolant Temp Sensor bad. $189 diag, parts and labor. Original estimates (I did have to go back once) $270.

Why did I have to go back? Really it's a good story which is why I am posting. The terminals to the sensor were badly corroded and initially this was thought to be the problem. Tech cleaned and reinstalled and tested. Light did not come back on so this was thought to have fixed it. Although I had to go back, I am very happy to have recieved dealer service where they did not 'throw parts at it' the first time, and took the most logical and inexpensive route. No labor was charged the second time.