pNutz

So I was driving back home from TX2K in Houston and about 3 hours into the trip the car said ESP was unavailable, please refer to owners manual. ESP was turned off and not too much longer I receieved a CEL. After scanning the car, the CEL came back as P2127- Throttle/ Pedal Position Sensor/Switch E Circuit Low Input.

The ESP issue will temporally fix itself after a simple restart but comes back as soon as i start driving the car. Also when stepping on the gas from a stop, the car seems to be really touchy on how much gas i'm trying to give it and when I accelerate hard, the car won't respond and gradually increases speed.

Can anyone tell me what sensor I need to replace or had an issue similar to mine?

Diabolis

Could be anythign from a faulty pedal position sensor to a bad/oxidized connector, a short in the wiring to the ECU itself in order of decreasing probablility. Google the error code and you'll find a couple of decent writeups how to perform testing and determine whether it's the sensor itself, bad connection or wiring or the ECU (none of the write-ups are MB specific, but they all operate on the same principle). There is a dual hall-effect pedal position sensor that varies the voltage, so with an OBD2 diagnostic tool and a multimeter you shoud be able to narrow it down.

Merc63

Take the pedal off the floor and test it for resistance.

It's easy to take off a couple bolts and a wire clip and the whole unit comes off. I have an extra throttle unit sitting in the basement if you need.