Advanced Diagnostics

Advanced Diagnostics - DTC P065A: ACG No Charging Malfunction

General Description






The alternator is driven by the engine, and it generates electricity according to the commands from the powertrain control module (PCM). The LIN line is connected to the alternator and transmits/receives information to/from the PCM. The voltage regulator in the alternator self-diagnoses the condition of itself, and by the PCM demands, the results are transmitted via the LIN line. If the self-diagnosed results are judged as generation unable or alternator rotation stop, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status






Enable Conditions






Malfunction Threshold
Either one of the conditions is met for at least 5 seconds:
- B terminal voltage is regulated voltage or more, and F terminal voltage is HIGH.
- B terminal voltage is 10 V or less (when the alternator speed is 3,000 rpm or less), or 11 V or less (when the alternator speed is 3,000 rpm or more).
- P terminal voltage is 2 V or less (when the alternator speed is 3,000 rpm or less), or 6 V or less (when the alternator speed is 3,000 rpm or more).
- Alternator speed is 400 rpm or less.

Possible Cause

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

- Alternator internal failure (voltage regulator failure)
- Alternator rotation defection

Diagnosis Details

Conditions for setting the DTC
When a malfunction is detected, a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory. The MIL does not come on.

Conditions for clearing the DTC
The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.