Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information

Condition




Diagnostic trouble code (DTC) EFI-123 is stored if the engine coolant temperature (ECT) sensor circuit is short-circuited to ground / voltage or if there is an open-circuit in the circuit that the control module interprets as a fault.

Substitute value
- If the intake air temperature (IAT) is lower than 10 °C the engine coolant temperature (ECT) is taken as -20°C at start.
- If the intake air temperature (IAT) is higher than 10° C the engine coolant temperature (ECT) is taken as 30° C at start.
- After starting the engine coolant temperature (ECT) is calculated theoretically.
- Initial boost pressure.
- The A/C is switched off.

Possible source

Signal too high:
- Short-circuit to supply voltage in the signal cable.
- Open-circuit in the signal cable or ground lead.
- Faulty engine coolant temperature (ECT) sensor.

Signal too low:
- Short-circuit to ground in the signal cable.
- Faulty engine coolant temperature (ECT) sensor.

Fault symptom[s]
- Difficult to start in certain temperature ranges.
- Poor performance.
- The engine cooling fan (FC) operates constantly.