2000 E55 ETA not responding to throttle input

[az762nato]

Putting the key in position 2 results in the throttle body moving to the wide open position, if you then start the car it tries to rev up because of it, but only gets to about 3500 or so before it realizes it and closes the throttle body. At that point, the car will not open the throttle at all, and is stuck in the limp mode where it only allows you to hit about 2000 RPM, and it does it via modulating the injectors only. We tested both circuits of the pedal position sensor under the hood, both good but replaced with a new unit anyways. The two voltage output pins have correct voltages, and testing those wires at the ecm also shows correct voltages. Pulled the ETA today and installed it in another car. ETA acts as it should in the other car, but when it goes back into the car with the trouble, it goes right back to having issues. If the car had other issues that were fixed, could it be stuck in this like a "limp mode" until it gets the ECU reset with dealer software? Car is a 2000 E55, no CEL, esp light IS on however.

[eric242340]

Originally Posted by az762nato

Putting the key in position 2 results in the throttle body moving to the wide open position, if you then start the car it tries to rev up because of it, but only gets to about 3500 or so before it realizes it and closes the throttle body. At that point, the car will not open the throttle at all, and is stuck in the limp mode where it only allows you to hit about 2000 RPM, and it does it via modulating the injectors only. We tested both circuits of the pedal position sensor under the hood, both good but replaced with a new unit anyways. The two voltage output pins have correct voltages, and testing those wires at the ecm also shows correct voltages. Pulled the ETA today and installed it in another car. ETA acts as it should in the other car, but when it goes back into the car with the trouble, it goes right back to having issues. If the car had other issues that were fixed, could it be stuck in this like a "limp mode" until it gets the ECU reset with dealer software? Car is a 2000 E55, no CEL, esp light IS on however.

You will get nowhere with this problem without reading the fault codes, then clearing the codes and road test, then read the codes again. The ESP light on is significant, but without the codes, there is no answer.