Diagnostic Trouble Code (DTC) Information ECM-950C

Condition

Fig 1: Identifying Accelerator Pedal (AP) Position Sensor

Courtesy of VOLVO CARS CORPORATION

The engine control module (ECM) checks the pulse width modulation (PWM) signal and the analog signal from the accelerator pedal (AP) position sensor.

The analog signal from the accelerator pedal (AP) position sensor is connected directly to the central electronic module (CEM). The signal is transmitted via CAN communication from the central electronic module (CEM) to the engine control module (ECM). The PWM signal is connected directly to the engine control module (ECM).

The diagnostic trouble code (DTC) is stored if the engine control module (ECM) registers a malfunction in the signals from the accelerator pedal (AP) position sensor.

The diagnostic trouble code (DTC) can be diagnosed when the ignition is switched on.

Substitute Value

Filtered accelerator pedal signal when accelerating
Acceleration is ignored when braking
In the event of a detected malfunction in one of the signals from the accelerator pedal (AP) position sensor, the other signal is used.

Possible Source

Analogue signal too high

Troubleshoot the central electronic module (CEM).

Analogue signal too low

Troubleshoot the central electronic module (CEM).

Pulse width modulation (PWM) signal too high

Short-circuit to ground in the signal cable.
Open-circuit in the signal cable.

Pulse width modulation (PWM) signal too low

Short-circuit to ground in the signal cable.
Short-circuit to voltage in the signal cable
Open circuit in the signal cable
Open circuit in the voltage feed.
Open circuit in the ground cable.
Damaged accelerator pedal (AP) position sensor.

Incorrect pulse width modulation (PWM) signal

Loose connections or contact resistance in the terminals on the pulse width modulation (PWM) signal cable
Interference on the pulse width modulation (PWM) signal cable
Damaged accelerator pedal (AP) position sensor.

Comparison error

Loose connections or contact resistance in the terminals on the analog signal cable
Malfunction of voltage feed to the analog signal.
Malfunction in the analog signal's ground
Malfunction in the pulse width modulated signal cable between the engine control module (ECM) and the accelerator pedal (AP) position sensor
Damaged accelerator pedal (AP) position sensor.

Incorrect signal

Malfunction in the control area network (CAN) communication between the engine control module (ECM) and the central electrical module (CEM)
Troubleshoot the central electronic module (CEM).

Fault symptom[s]

Poor accelerator pedal (AP) response
The accelerator pedal (AP) is ignored when braking.
Message in the display.
Vehicle's max. speed limited.