I was futzing with the air cleaner last night. This morning, the check engine light came on and stayed on. The kindly advisor at the dealer did something near the battery, read out code 13, and reset the check engine light. For my sanity, what fault/s does code 13 represent?

Thanks,
Sixto
78 450SEL ... don' need no steenkeeng check engine light
91 300SE

Look at this site:

http://www.batauto.com/MB.html

I think your car is in the last group listed. The codes seem good but they have the wrong years listed for some of the engine sizes.

How's "intake air temperature reading is implausible" sound to you. Sounds like the key was turned on when the air cleaner was off.

Thanks all. Is that fault said in one word in German? I did run the engine with the air cleaner off and thus air temp sensor disconnected.

Sixto
78 450SEL
91 300SE