There is a test module to detect actual sluggish movement of an accelerator pedal as well as to detect a fault in the plausibility check between accelerator and brake pedal. Any malfunction of the accelerator pedal is determined with simultaneous actuation of the accelerator and brake pedal while the vehicle is being driven.
A plausibility fault is set in the engine management system if a driver request is detected via the accelerator pedal for at least 1.5 seconds and in relation to this there is a brake signal. Here, the brake pressure is used as a measured variable. This prevents braking deceleration being stopped by a jamming accelerator pedal.
In the case of the S54 engine in the M Roadster, the two accelerator-pedal-travel sensors within the accelerator pedal module are supplied with a voltage of 4.8 Volts to 5.2 Volts. During actuation of the pedal, the centre pick-offs of the sensor supply a voltage between 0.5 or 0.25 Volts (unactuated) and 4.0 or 2.0 Volts (actuated).
As long as the driver request and brake pressure are present, the vehicle does as follows: The engine management system reduces the driver request relative to the brake pressure. If the brake pressure increases, the driver request is taken back accordingly by the engine management system.
The perceptible effect for the driver creates a feeling similar to ”taking your foot off the accelerator pedal”.
The accelerator pedal module may only be replaced if there is an express customer complaint regarding increased, constant idle speed and / or a mechanically jamming accelerator pedal as well as the fault entry. The fault entry alone does not justify component replacement!
In the case of a multiple fault entry, the customer is to be informed of his or her possible incorrect operation (simultaneously operating the accelerator and brake pedals).
Possible customer complaints that can be proven by a stored fault can be customer statements regarding low power, coasting cutout while the vehicle is being driven as well as an increased constant speed with jamming accelerator pedal.