Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information

Condition




The accelerator pedal position sensor has two different internal sensors, where one generates an analogue signal and the other a pulse-width modulated (PWM) signal. If the engine speed is higher than 600 rpm and Engine control module (ECM) detects any of the following faults on the pulse-width modulated signal (PWM) which comes from the accelerator pedal position sensor:
- The pulse ratio is lower than 3 % for longer time than 0.15 seconds, then diagnostic trouble code ECM-9520, Signal too low, is generated.
- The pulse ratio is higher than 97% for longer time than 0.15 seconds, then diagnostic trouble code ECM-9520, Signal too high, is generated.
- The frequency is lower than 100 Hz for longer time than 0.05 seconds, then diagnostic trouble code ECM-9520, Faulty signal, is generated.
- The frequency is higher than 300 Hz for longer time than 0.15 seconds, then diagnostic trouble code ECM-9520, Signal missing, is generated.
For upgraded software, released during year 2006 or later, the above detection times are increased from 0.3 to 0.7 seconds.

For more information about the electronic throttle system and related components such as the electronic throttle module, accelerator pedal position sensor, brake light switch, clutch pedal position sensor, and brake pedal position sensor: Design Design

Substitute value

Slow opening of throttle.
The throttle opens slower than during normal requested open because the system is regulated by only one of the pulse width modulated signals from the accelerator pedal position sensor. The driver may notice that the engine responds a bit slower compared to normal throttle application.

Closing of throttle during braking.
The accelerator pedal position is ignored when the brake pedal is depressed.

Possible source

Signal too high:
- Short-circuit to battery voltage in the signal cable.

Signal too low
- The signal cable is short-circuited to ground.
- Damaged accelerator pedal (AP) position sensor.

Signal missing:
- Open circuit on signal cable.
- Loose connections or contact resistance in the terminals on the pulse width modulation (PWM) signal cable.
- Damaged accelerator pedal (AP) position sensor.

Faulty signal:
- Damaged accelerator pedal (AP) position sensor.

Fault symptom[s]
- the accelerator pedal (AP) is ignored when braking
- slow response during acceleration