Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information ECM-U012000

Condition




The Engine control module (ECM) regulates the alternator's charge voltage, via LIN communication, on the request of the Central electronic module (CEM), via CAN communication.
The diagnostic trouble code is stored if the control module detects:
- No communication with the Alternator control module (ACM).
The control module's test for the diagnostic trouble code (DTC) starts in the event of:
- Ignition on.

Note! The control module can only detect the fault once the test has been started and the diagnostic trouble code (DTC) is stored when the conditions are met.

Substitute value
- The alternator control module (ACM) (charge regulator) charges with a fixed voltage of 13.8 V.

Possible source
- Contact resistance or oxidation on connections
- LIN-cable short-circuited to voltage.
- LIN-cable short-circuited to ground.
- Open circuit on LIN-cable.
- Internal fault in another unit in the same part of the LIN network.
- Damaged alternator control module (ACM) (charge regulator).
- The alternator with charge regulator is not designed for LIN communication.
- Damaged engine control module (ECM).

Fault symptom[s]
- Battery discharged.
- Low starter motor rpm.
- The engine judders under acceleration