DTC Troubleshooting

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 Initial Inspection and Diagnostic Overview.
- If a high voltage battery (24 V, etc.) is connected to the vehicle, this DTC can be stored.

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 P or N) 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 go to step 7.

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.

7. Turn the ignition switch to ON (II).

8. Reset the PCM with the HDS.

9. Do the PCM idle learn procedure PCM Idle Learn Procedure.

10. Start the engine.

11. Check under these conditions:

- A/C off
- Headlights off
- Rear window defogger off

12. Hold the engine speed at 3,000 rpm (in P or N) for 1 minute.

13. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P1549 indicated?

YES -

Check for poor connections or loose terminals at the alternator and the under-hood fuse/relay box, then go to step 1.

NO -

Go to step 14.

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

Does the HDS indicate PASSED?

YES -

Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 13, go to the indicated DTC's troubleshooting.

NO -

If the HDS indicates FAILED, check for poor connections or loose terminals at the alternator and the under-hood fuse/relay box. If the PCM was updated, substitute a known-good PCM, then go to step 10. If the PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, go to step 10.