Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information ECM-1200

Condition




The diagnostic trouble code (DTC) (Signal too high or signal too low) is stored if the engine control module (ECM) detects that the signal for the intake air temperature corresponds to a temperature that is higher or lower than a certain value.
The diagnostic trouble code (DTC) (Faulty signal) is stored if the engine control module (ECM) detects that the signal does not follow the intake air temperature (IAT) sensor characteristics over a period of time.
The diagnostic is active when the engine has been running for 3 minutes and the engine has been idling for at least 1 minute.

Substitute value
Predefined value for intake air temperature.
Three-way catalytic converter (TWC) preheating and idle air trim diagnostics are disabled.

Possible source

Signal too high
- Short-circuit to ground in the signal cable
- Damaged intake air temperature (IAT) sensor.

Signal too low
- Contact resistance in the terminals
- Open-circuit in the signal cable
- Short-circuit to supply voltage in the signal cable
- Damaged intake air temperature (IAT) sensor.

Faulty signal
- Contact resistance or oxidation in the intake air temperature (IAT) sensor terminals
- Damaged intake air temperature (IAT) sensor.

Fault symptom[s]
- Malfunction indicator lamp (MIL) lit
- Poor performance.