Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information ECM-921C

Condition




The diagnostic trouble code (DTC) is stored if the engine control module (ECM) registers a fault in the signal from the throttle position (TP) sensor, potentiometer 1 (circuit 1) in the electronic throttle unit.
The diagnostic trouble code (DTC) can be diagnosed when the ignition is switched on.

Substitute value
The throttle angle is calculated using potentiometer 2 (circuit 2) in the throttle position (TP) sensor for the throttle unit. If the diagnostic trouble codes (DTCs) for both potentiometers 1 and 2 are stored at the same time, the supply to the damper motor in the throttle unit will be disabled. The throttle will set itself to the return position.

Possible source
- Contact resistance or oxidation in the terminals between the engine control module (ECM) and the electronic throttle unit
- Open-circuit or short-circuit to supply voltage in the signal cable
- Open-circuit in the signal ground cable for potentiometers 1 and 2
- Damaged throttle unit.

Fault symptom[s]
- Poor performance.