2001 Mercedes-Benz SLK320 3.2L Engine Light is On with No Acceleration

1. Connect scan tool and monitor voltages of pedal sensor B37. Signal 1 (Accelerator pedal position: Idle speed):[0.2...0.5] V Signal 2 (Accelerator pedal position: Idle speed):[0.1...0.5] V Signal 1 (Accelerator pedal position:Kickdown):[4.3...4.8] V Signal 2 (Accelerator pedal position:Kickdown):[2.1...2.5] V
2. If voltages are out of specification verify correct reference voltage to sensor by measuring between pins 6 (Black/White wire) and pin 1 (Blue/Grey wire) on pedal sensor connector. Voltage needs to be between 4.75 and 5.25 volts.
3. Test throttle body voltages with scan tool. Potentiometer #2 signal voltage ignition on, accelerator pedal position CTP 0.3-0.9 VDC, WOT > CTP value Potentiometer #1 signal voltage Ignition on, accelerator pedal position CTP 4.0-4.6 VDC, WOT < CTP value.
4. Test mass air flow sensor voltage. Sensor signal voltage must start KOEO around 1 volt and go up as engine RPMs increase. This can also be seen under air sensor volume output, output value must go up not down

Tech Reported Fix Details Confirmed Fix Alan Takeshita January 04, 2010 2001 Mercedes-Benz C320, 3.2L * Replaced Accelerator Pedal Position Sensor B37 42,939 miles Accelerator Pedal Position Sensor B37 Chris Meyers August 21, 2009 2000 Mercedes-Benz ML320, 3.2L * Replaced Accelerator Pedal Position Sensor B37 Replaced Throttle Body Performed Throttle Body Relearn — Had to send to dealer to perform relearn. Fault code did not go away with new parts installed until the relearn was performed. Accelerator Pedal Position Sensor B37, Throttle Body, Throttle Body Relearn.

Source