DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: P1549

DTC P1549 : Charging System High Voltage

NOTE:
* Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information How To Troubleshoot The Fuel And Emissions Systems.
* If a high voltage battery (24 V, etc.) is connected to the vehicle, this DTC can be stored.

1. Problem verification:

Problem verification
-1. Turn the ignition switch to ON (II).

-2. Clear the DTC with the HDS.

-3. Start the engine.

-4. Check under these conditions:
* A/C off
* Headlights off
* Rear window defogger off

-5. Hold the engine speed at 3,000 rpm (in neutral) for 1 minute.

-6. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P1549 indicated?
-YES- Replace the alternator Removal and Replacement, then do the repair verification.
-NO- Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the alternator and the under-hood fuse/relay box.

Repair verification (OBD STATUS check):

-1. Turn the ignition switch to ON (II).

-2. Reset the ECM with the HDS How To Troubleshoot The Fuel And Emissions Systems.

-3. Do the ECM idle learn procedure ECM/PCM Idle Learn Procedure.

-4. Start the engine.

-5. Check under these conditions:
* A/C off
* Headlights off
* Rear window defogger off

-6. Monitor the OBD STATUS for DTC P1549 in the DTCs MENU with the HDS.

Does the HDS indicate PASSED, FAILED, or NOT COMPLETED?
-PASSED- Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated, go to the indicated DTC's troubleshooting.
-FAILED- Go to step 1 and recheck.
-NOT COMPLETED- Meet the test condition, and check the OBD STATUS again.