Engine continues to run when the KEY is taken off the IGNITION......


Asked by Apr 05, 2013 at 01:09 AM about the 2000 Mercedes-Benz CLK-Class CLK 320 Coupe

Question type: Maintenance & Repair

This car seems to be possessed. When I turn off the ignition and take the keys out while the headlights (HID) are on, the engine is still running. Once I turn off the headlights, the engine stops (with the keys off the ignition). The headlights has to be off for the engine to turn off  'normally'.

When you try starting the engine with the headlights on, it would crank - no start. When the headlights are off, the engine would start normally.

The car has about 121K miles on it. Thank you so much!

8 Answers

well the continuing to run without the key in can be attributed to a phenomenon known as diesling, where if you put it back in gear, will stop. The battery is weak and needs to be replaced as the age of this one is probably more than ten years old and stopped accepting a charge three years ago~ lights will behave themselves if you clean the ground connection to chassis and take a look at the connection to the block as well upon installation of your new battery~


Makes you wish you still had your '91? Sounds like you have figured out the secret anti theft sequence that your car has devised. It doesn't make sense that no lights shut it down and let it start. Lights on keep energy to the coils if it's running and prevents energy to the coils if trying to start... Something is backfeeding.

Yeah TS I was thinking something similar. The lights will go off when starter motor is engaged, that would account for the 'no start when lights on' I winder if a short is in the headlight relay/solenoid..'backfeeding' is s good choice of words, this sure is an odd one ..maybe a new relay


Did you get this sorted in the end ? my car is doing exactly the same thing and i cant figure out what is wrong with it ? Thanks Lisa x

2 of 2 people found this helpful.

Thanks for all the responses. Just saw all these now. It is my son's car and he has this car in college. He says it only happened that one time. Weird. I will have the battery checked when he comes home this summer. Other than that, it is a great car that gets very good gas mileage. tenspeed, you remembered my '91? ~~~ after replacing head gasket, the timing chain broke after a few months. She is roadworthy again for the past year with over 200K and still getting 26 mpg hwy. Recently, it has a check engine light right before it has to be smogged for CA registration.


Engine continues to run when the KEY is taken off the ignition, Mercedes 1988 560sl. Anybody help please, alternator was changed was fine for 2 days and now same problem.

9 of 9 people found this helpful.

My car is doing the same thing. It made a funny noise when I tried starting it....I was able to drive my car down the road, but it kept making a funny noise. So I stopped the car, but the engine kept going. I took the keys out, still the engine wouldn't stop. Any ideas? Please help!

4 of 4 people found this helpful.

Jumpin connectios, or same as paralell connections Is most likely the problem... Both lights and engine switch have same power source. But ignition some how due to jumpers hace Power sources. Trace wires con the most common plc fuse box or hood compartment.pero cables could olso be at blame.gd luck..

1 of 1 people found this helpful.

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