DTC ECM-903F

Condition







Diagnostic trouble code (DTC) ECM-903F, signal too low or missing, is stored if the engine control module (ECM) detects that the actual throttle angle (measured by the throttle position (TP) sensor) deviates from the requested throttle angle (the target value from the engine control module (ECM)). ECM-903F, signal too low is stored if the target value changes and the actual throttle deviates >20% from target value. ECM-903F, signal missing is stored if the target value is set and the throttle deviates 5% from target value. The diagnostic has small tolerances and the function may be difficult to check by reading off parameters.

Diagnostic trouble code (DTC) ECM-903F, signal too high, is stored if the engine control module (ECM) detects a faulty signal via the controller area network (CAN) from the electronic throttle module (ETM) (ETM).

Substitute value
- the accelerator pedal (AP) is ignored when braking
- the cruise control switched off
- the engine speed (RPM) is limited using fuel shut off. The maximum permitted engine speed depends on the accelerator pedal (AP) position.

Possible source

Signal too low or signal missing:
- low power supply to the electronic throttle module (ETM) (loose terminals or contact resistance in the terminals, low system voltage)
- faulty software in the electronic throttle module (ETM)
- contaminated electronic throttle module (ETM) (oil film, dust etc.)
- defective electronic throttle module (ETM).

Signal too high:
- low power supply to the electronic throttle module (ETM) (loose terminals or contact resistance in the terminals, low system voltage)
- defective system relay (delayed switch on)
- loose connections or contact resistance in the terminals for the CAN
- defective wiring for the control area network (CAN)
- interference on the CAN signal wiring
- defective electronic throttle module (ETM)
- another node in the high-speed control area network (CAN) is defective.

Fault symptom[s]
- the accelerator pedal (AP) is ignored when braking
- the cruise control is not functioning at all
- uneven idle
- jerks during engine braking.