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Marty
Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 53904
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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I have a 2001 s430. When I start the car the rpms hit 2200

Customer Question

I have a 2001 s430. When I start the car the rpms hit 2200 briefl'y then settle down to normal idle of about 700 rpm. I don't know if it's related or not but if I excelerate all the way to the floor past where I feel something like a kick down switch the car will loose power. You can still go as fast as before but takes a long time to get there. From a dead stop it feels like an old locomotive. If I turn the key off and restart, everything is as before and runs fine. The high rpm on start is almost the same weather the engine is warm or cold.It's slightly higher when cold.
Submitted: 6 months ago.
Category: Mercedes
Expert:  Marty replied 6 months ago.

Hi Eric, welcome to Just Answer. My name is***** sounds like a fault with the electronic throttle actuator. When the actuator malfunctions the idle can be erratic. When you accelerate hard the actuator can default to a limp home mode if a malfunction is detected. When you turn the key off and back on it will reset the actuator and everything will work fine until the fault is detected again. I suggest having the car connected to a Mercedes tester to check for fault codes stored. I would also suggest having the actuator inspected and cleaned. You may need to replace the throttle actuator to repair this problem.

Let me know if you have any questions. And please remember to rate my service :-)

Marty

Customer: replied 6 months ago.
My main concern is the high rpm on start up. I mentioned the rest so you would have more information. Are you talkin about the device on the bottom of the gas pedal or the throttle body. These parts are expensive so I want to be reasonably confident that I need what I buy. My code scaner will not comunacate with this car. I don't think it's the tool because it will work with my 99 320 and 2006 c230. I mention this for your info. Eric
Expert:  Marty replied 6 months ago.

You need to get the fault codes to be any more specific but this sounds most like a bad throttle actuator. The pedal would not cause this issue.

Customer: replied 6 months ago.
Alright let's try that. Just to be clear.....Are you talking about the throttle body air intake actuator with the butterfly in it and a wire that plugs into it or a throttle actuator sensor that is a flat plastic box where wires plug into the back of it?
Expert:  Marty replied 6 months ago.

Yes, that is the part I am referring to.

Customer: replied 6 months ago.
Hi MartyStill confused, the metal throttle body piece or the square plastic sensor? When I search the part 2 different ones come up in the description. Is it the throttle body piece with the butterfly in it?
Expert:  Marty replied 6 months ago.

I am referring to part number 113 141 01 25. Click on the image below.