DTC ECM-902A

Condition







The control modules communicate with each other in a network via a standardized serial communication method - CAN (Controller Area Network).

Diagnostic trouble code (DTC) ECM-902A, signal missing, is stored if there is no communication between the engine control module (ECM) and electronic throttle module (ETM) or if the signal from the electronic throttle module (ETM) is not updated.

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
- the electronic throttle module (ETM) follows the pulse width modulation (PWM) accelerator pedal signal directly, the control signal via the control area network (CAN) is ignored.

Possible source

Signal missing
- delayed system relay start when the ignition is switched on
- the power supply to the electronic throttle module (ETM) when the ignition is switched on (signal too high), or when running (signal missing)
- loose connections or contact resistance in the terminals for the CAN
- interference in the control area network (CAN) wiring
- defective control area network (CAN) wiring
- defective electronic throttle module (ETM)
- another node in the Control area network (CAN) is defective.

Fault symptom[s]
- the accelerator pedal (AP) is ignored when braking
- the cruise control cannot be activated
- uneven idle
- jerks during engine braking.