It all started one evening when I was driving my mercedes benz c180 (W203) year 2001 Europe made saloon car (manual transmission) when the display panel showed "ESP. Visit Workshop". The rpm then started oscillating between 10-15 whether I step on the accelerator pedal or not. The car could not move so I have to tow it home. Now the display reads "ESP. Unavailable" after I toyed with some fuses. I am quite a distance away from an authorised mercedes benz agent and the car crawls and jerks. What should I do?

 

change the IVM sensor

 

What is IVM sensor? Can you give me the full detail on IVM, pls?

 

think your car has a very simple problem. brake light switch! if every fuse is good then probably you need to change that switch. even if your brake lights are good! the switch operates more than one circuit and the other one is for the esp. but u need a work shop anyway to clear the codes. this switch is cheap and goes bad all the time so it is a good thing to change it. but i would say u need to scan the car b4 u start to buy things wo diagnostic. because can be something else 4 instant the steering angle sensor,too.

 

My problem was solved by replacing the Accelerator Pedal Assembly (ie the APP sensor) after a diagonistic indicated the problem to be with the throtle and/or acceleration. After replacing the Acc. Pedal Assembly the ESP error message also went away. What baffles me is how the ESP is linked to the APP sensor. The ESP is linked from the literature to the braking system; why should the display give me ESP when the APP sensor is bad is what I dont understand. My Accelerator assembly had an inset with a 2-pin cable leading from it. The accelerator pedal presses on it when fully down. The mb part number on it is 005-545-22-14. Can somebody tell me what the function of this unit is, pls? How can one test whether an oxygen sensor is good or bad, outside the vehicle (ie when not plugged into its receptacle in the car)?

 

your brake system and your engine computer work together. when u drive your car your brake works without you all the time via ESP. that's the point of this system. if you would make a fast curve and you would give to much gas and one of your rear tire would start to "smoke" then your ESP system would operates that brake only. that is the link between your gas padal and your esp light. your brake works so many times you have no idea. if you unplug your esp unit and start the car then your engine will idling only. in this case u would give gas then nothing will happen. they can't exist wo each other.
the O2 sensor can be checked with a scanner only. when u go the actual values with an appropriate scanner then you will see each o2 sensor's Mvolt reading. if the number is running up and down quickly then the sensor is good. but you have to have trained eyes to see it is slow and lazy or good. besides this the sensor still can be bad if the heater circuit is bad. in this case you have a check engine light on when the engine is cold,only.

 

Dear Csapi,
Thanks for your response. But you forgot to answer my last question; as stated below:
My Accelerator assembly had an inset with a 2-pin cable leading from it. The accelerator pedal presses on it when fully down. The mb part number on it is 005-545-22-14. Can somebody tell me what the function of this unit is, pls? How can one test whether an oxygen sensor is good or bad, outside the vehicle (ie when not plugged into its receptacle in the car)?

 

that's just a built in switch. that switch tells to the computer when u hit the gas fully. when this switch's circuit closed then your engine control module opens the throttle body fully,gives maximum advance ignition till the knock sensors allow it, injector pulse are longer,air pump starts to work etc. that switch would be bad then the DAS diagnostic scanner would be able to give u a code. once it fails to give the CAN signal then the computer sets a stored code for that. (check freeze frame data)
I'm not aware of any reliable test for the O2 sensor outside of the car. Think scanner, only.