Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information ECM-8400

Condition
The diagnostic trouble code (DTC) is stored if the engine control module (ECM) detects that the 5 volt supply circuit for sensors has a voltage higher than 6 V (high signal) or lower than 4 V (low signal) and it is interpreted as a fault.

Substitute value
- None.

Possible source

Signal too high
- Short-circuit to battery voltage in the 5 volt supply cable
- Damaged sensor connected to the 5 volt supply cable.

Signal too low
- short-circuit to ground in the 5 volt supply cable
- Damaged sensor connected to the 5 volt supply cable.

Fault symptom[s]
- Deterioration in performance
- Uneven idle.