So I drive a 1995 Mercedes E320 which I love to death. About a year ago the head gasket was changed, and long story short, the throttle actuator wiring harness had to be reinsulated due to some garbage laws about biodegradable wiring insulation in Germany. Long story short, I rewired the actuator, and it worked like a dream for about a year. The other day my actuator, or so I think, begins to fail. My asr (or traction control) light comes on and the car goes into a safety limp mode which mechanically operates the throttle actuator at a limited capacity. This was the same symptom as last time. Well I talk to my mechanic and he recommends having the actuator professionally rebuilt. So I pull the actuator tonight to find that without the motor running, only electricity on, the actuator is fully functional without the gas running through it, but as soon as its reinstalled and the motor is started, it quits. Anyone know anything about Mercedes motors got a clue what I should do? I dont want to drop hundreds of dollars to rebuild an actuator which may not be the problem. Know its a long shot on here, but hey all it takes is one answer... Thanks for the help yall
- Thread starter Rebel
- Start date
check all up stream wiring harness function and flow......i'm not a mechanic, but trouble shoot the conduit and look for any breaks in wiring and or corrosion,,,,,just sayin
Just a thought. You said the traction control light comes on then it derates or "limps". Possibly there is a issue with one of the abs sensors that is showing one wheel either moving at a different rate of spin or seeing a wheel not turning. I'm not sure what the Mercedes system uses as a de-bounce time ( The time a code must be present before actually logging a code verses just light illumination".) But it is something to check based on the symptom you describe. The whole purpose of traction control is to limit power in a wheel spin situation. Not saying that this is your issue but I would check it.. It will require hooking a code scanning/diagnostic computer to the system and accessing the ABS system. Spin each wheel one at a time and see if the ABS ECU is seeing that wheel spinning while the others are stationary. If one doesn't see any spin or it intermittently reads it, that wheel speed sensor or wiring might be your problem. The ABS on most makes is where the traction control gets it's info on wheel speed/spin. I hope this helps in finding the issue.
That's the best idea I can think of since during a key on-engine off the actuator functions normally.
That's the best idea I can think of since during a key on-engine off the actuator functions normally.
I'm no Mercedes expert but it sounds like you may be having a ground issue. When not running it may be finding a path to ground through another component. But when you start it, that other component may activate causing a loss of ground. I would find the ground and see if is going away once the engine is started. If it is, work backwards to the place that it is being lost.
Just a guess.
Just a guess.
I dont think the abs is the source of the problem, but I could be wrong. In the Mercedes system, the throttle is linked to the traction control. When the throttle actuator is functioning properly the throttle linkage moves a lever on the actuator which opens and closes the valve through an electronic motor. When it is not functioning properly, the device simply shuts down. However in the upper range of the throttle linkage lever, the valve is mechanically operated to a limited extent when the device is not functioning, allowing you to drive the car in a limited capacity. This is the limp mode I was talking about. Im just confused how it could work when the electronic is on and not gas and then shut off. Perhaps it is a ground issue like another poster said.
Any other ideas?
My attempt at sarcasm. What did the Mercedes forum say?
So when you rewired the actuator did you splice any wires. Could they have come loose. Do you have a factory service manual (fsm)? In the fsm there are testing parameters to check the electric shit.
In all seriousness. Get a good car forum. Get an fsm. If your actuator worked great for a year my first guess is that another sensor or something on the traction control is messed up and would look towards that way.
So when you rewired the actuator did you splice any wires. Could they have come loose. Do you have a factory service manual (fsm)? In the fsm there are testing parameters to check the electric shit.
In all seriousness. Get a good car forum. Get an fsm. If your actuator worked great for a year my first guess is that another sensor or something on the traction control is messed up and would look towards that way.
Reread your first post. What other inputs does the actuator receive when the motor is on that it does not receive when off?
I know lots about engines...nothing about Mercedes. They do things a bit, lets just say, different. Sorry I couldn't help/
It could and maybe more likely to be a bad clutch coil within the actuator (would trip ASR light IIRC)or possibly a vacuum leak- both which could manifest into seeming like the actuator....
This may help: https://www.youtube.com/watch?v=CRLJBgX-ZcM and https://www.youtube.com/watch?v=F5G5ZmgFonk
To verify these videos are accurate, you could probably find out what values to expect per position from a FSM or perhaps a friendly VDO/Mercedes parts rebuild shop?
Hope this helps.
This may help: https://www.youtube.com/watch?v=CRLJBgX-ZcM and https://www.youtube.com/watch?v=F5G5ZmgFonk
To verify these videos are accurate, you could probably find out what values to expect per position from a FSM or perhaps a friendly VDO/Mercedes parts rebuild shop?
Hope this helps.
