On my 1996 E320 in the center display I get the "Check Engine" and "Check Electronics" messages. The car hesitates on acceleration at low speeds but only intermittently. When a mechanic plugged into the panel and checked the error code, it said "undefined error code". He reset the display, but it came on again 2 days later. Any ideas on what is causing the messages to come on? I recently had the security/locking module (on the rearview mirror) replaced. Could that be related?

 

not related.

get a tune-up