Diagnostic Trouble Code (DTC) Information

ECM-902B THROTTLE UNIT COMMUNICATION
DIAGNOSTIC TROUBLE CODE (DTC) INFORMATION




Condition
The control modules communicate with each other in a network via a standardized serial communication method - CAN (Controller Area Network). The engine control module (ECM) has registered a fault in the communication on the CAN network. The CAN signal from the throttle unit (ETM) is missing or not updated. Diagnostic trouble code (DTC) ECM-902B is stored in the engine control module (ECM).

Substitute value
- the accelerator pedal (AP) is ignored when braking
- the cruise control cannot be activated
- the engine speed (RPM) is limited using fuel shut off. The maximum permitted engine speed depends on the accelerator pedal (AP) position
- the throttle unit follows the pulse width modulation (PWM) accelerator pedal signal directly, the control signal via CAN is ignored.

Possible source
- the power supply to the throttle unit
- loose connections or contact resistance in the terminals for the CAN
- open-circuit in one or both CAN signal cables
- short-circuit to ground, voltage or each other in one or both of the CAN signal cables
- interference on the CAN signal wiring
- defective node in the Control area network (CAN)
- defective throttle unit.

Fault symptom[s]
- the accelerator pedal (AP) is ignored when braking
- the cruise control cannot be activated
- uneven idle
- jerks during engine braking
- the ETS warning lamp lights (C70 and S/V70 -2000 only).