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Marty
Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 53310
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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You have helped me out in the past so I requested you again.

Customer Question

Hi Anthony, you have helped me out in the past so I requested you again. I fixed my misfire issue. It was a bad transformer. Current problem I'm having now is when I got full throttle/kickdown I lose 75% of my power and I don't get it back until I restart
the car. Any ideas on what could be causing this?
Submitted: 1 year ago.
Category: Mercedes
Expert:  Marty replied 1 year ago.

Hi, perhaps I can help. It sounds like 1 of the 4 catalytic converters may be partially plugged. I would check the fault codes and see if you have codes for misfires on a group of 3 cylinders that share the same converter. If you do then I would suspect that the converter is plugged.

Customer: replied 1 year ago.
If possible I would like to talk to Anthony again. He helped me last time. Is this possible?
Expert:  Marty replied 1 year ago.

Good morning. I answered your question yesterday because I saw that Anthony has not been online for the last 2 1/2 weeks. If you would like to wait and see if he replies that is fine. I'll be happy to help you otherwise.

Marty

Customer: replied 1 year ago.
Hi Marty, I am not getting any misfire codes. The car runs strong and high speeds of over 100 are not a problem. The problem starts when using the kick down and It might have happened one time before I got to kick down. The car goes into what I think is limp home mode until I restart it then it's fine again. I pulled codes before I restarted and here is what I got. P0410 p0170 p0170. Any ideas?
Expert:  Marty replied 1 year ago.

What is your description of limp home mode?

Customer: replied 1 year ago.
I get on the pedal and it won't go anywhere until it's good and ready. Weather I'm driving or on idea in park it reacts the same way
Expert:  Marty replied 1 year ago.

The P0410 won't affect the engine running. The P0170 is a fuel mixture fault code and won't typically cause loss of throttle response. You listed the P0170 twice. Is there another code that you didn't list?

Customer: replied 1 year ago.
P0120
Expert:  Marty replied 1 year ago.

That's what I suspected. For this fault code you need to replace the accelerator pedal. When you floor the throttle or engage kickdown your signal from the pedal is dropping out and the throttle goes into limp home mode until you turn the key off.

Customer: replied 1 year ago.
I have changed it twice. does it need to be programed or is it plug and play? The pedals were taken from cars that were working and are not new
Expert:  Marty replied 1 year ago.

The pedal does not require programming. The P0120 is a generic fault code that can set for either the pedal or the throttle actuator. The most common failure is the pedal. The possible causes are the pedal, actuator, wiring or ECU. A factory scanner will give you a Mercedes fault code that is more specific. You really should get the car connected to a factory scan tool for a more accurate code reading.

Expert:  Marty replied 1 year ago.

Click on the link below for the possible factory codes.