Diagnostic Trouble Code (DTC) Information ECM-918F

Condition

Fig 1: Identifying PWM Signals From Accelerator Pedal Position Sensor To ETM

Courtesy of VOLVO CARS OF NORTH AMERICA.

If Electronic throttle module (ETM) detects that the pulse-width modulated (PWM) signal from the accelerator pedal position sensor is missing flank shifts for 0.1 seconds, this information is sent to Engine control module (ECM) which then stores diagnostic trouble code ECM-918F, Faulty signal.

For upgraded software, released during year 2006 or later, the above detection times are increased from 0.1 to 0.9 seconds.

See Identifying upgraded software ECM/ETM

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 Function

Substitute Value

Closing of throttle during braking.

The accelerator pedal position is ignored when the brake pedal is depressed.

The following only applies in combination with diagnostic trouble code ECM-911A and/or ECM-912A:

Throttle closed.

The electronic throttle module (ETC) deactivates the throttle motor control, which means that the throttle is not actuated and assumes its mechanical stop position. This means about 20% throttle opening. This reconfiguration is always followed by fuel cut-off.

Fuel cut-off that follows accelerator pedal position.

Engine speed is regulated via fuel cut-off by deactivating the injectors one at a time. Engine speed is determined by gas pedal position sensor position and engine speed is maximized to about 5000 RPM. This reconfiguration can cause the engine to idle very unevenly since the engine control module (ECM) regulates engine speed by cutting of the fuel to the cylinders individually. Do not confuse this reconfiguration (engine behavior) with an actual driveability problem that was present before reconfiguration.

Possible Source

Power supply missing
short-circuit to supply voltage in the signal cable
short-circuit to ground in the signal cable
open-circuit in the signal cable
loose connections
defective accelerator pedal (AP) position sensor
This diagnostic trouble code is generated in combination with other trouble codes. Information on the possible root cause is described.
See Information about combined diagnostic trouble codes (DTCs)

Fault symptom[s]

uneven idle
jerks during engine braking
very poor accelerator response
maximum speed approximately 50 km/h.