Diagnostic Trouble Code (DTC) Information ECM-120A
Condition
The engine control module (ECM) checks the signal from the intake air temperature (IAT) sensor in the intake manifold. The diagnostic trouble code (DTC) is stored if the engine control module (ECM) detects that the value from the intake air temperature (IAT) sensor deviates too much from the value of the engine coolant temperature (ECT) sensor after the engine has been switched off for an extended period.
The diagnostic trouble code (DTC) is diagnosed once per operating cycle when the ignition is switched on, but only when the engine temperature has dropped by approximately 55 °C from operating temperature since the previous operating cycle.
Substitute Value
- The value for the intake air temperature (IAT) is set at 30 °C.
Possible Source
- Contact resistance in the connector
- Damaged intake air temperature (IAT) sensor (in the mass air flow (MAF) sensor).
Fault symptom[s]
- Malfunction indicator lamp (MIL) lit.