DTC Troubleshooting
DTC Troubleshooting: P16BC (116-2)
DTC P16BC:
Alternator FR Terminal Circuit/IGP Circuit Low 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.
1. Check for poor connections or loose terminals at the alternator 4P connector.
Are the connections and terminals OK?
YES -
Go to step 2.
NO -
Repair the connections or terminals, then go to step 20.
2. Turn the ignition switch to ON (II).
3. Clear the DTC with the HDS.
4. Start the engine.
5. Check under these conditions:
- A/C on
- Temperature control at maximum cool
- Blower fan at maximum speed
- Rear window defogger on
- Headlights on high beam
6. Hold the engine speed at 2,000 rpm (in P or N) for 1 minute.
7. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P16BC indicated?
YES -
Go to step 8.
NO -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the alternator.�
8. Turn the ignition switch to LOCK (0).
9. Disconnect the alternator 4P connector.
10. Turn the ignition switch to ON (II).
11. Measure the voltage between alternator 4P connector terminal No. 1 and body ground.
Is there battery voltage?
YES -
Go to step 12.
NO -
Repair an open in the wire between the alternator (IG1 line) and the No. 18 ACG (15 A) fuse in the driver's under-dash fuse/relay box, then go to step 18.
12. Measure the voltage between alternator 4P connector terminal No. 4 and body ground.
Is there about 5 V?
YES -
Replace the alternator Removal and Replacement, then go to step 18.
NO -
Go to step 13.
13. Turn the ignition switch to LOCK (0).
14. Jump the SCS line with the HDS.
15. Disconnect PCM connector C (49P).
16. Connect alternator 4P connector terminal No. 4 to body ground with a jumper wire.
17. Check for continuity between PCM connector terminal C44 and body ground.
Is there continuity?
YES -
Go to step 27.
NO -
Repair an open in the wire between the PCM (C44) and the alternator, then go to step 19.
18. Turn the ignition switch to LOCK (0).
19. Reconnect all connectors.
20. Turn the ignition switch to ON (II).
21. Reset the PCM with the HDS.
22. Do the PCM idle learn procedure PCM Idle Learn Procedure.
23. Start the engine.
24. Check under these conditions:
- A/C on
- Temperature control at maximum cool
- Blower fan at maximum speed
- Rear window defogger on
- Headlights on high beam
25. Hold the engine speed at 2,000 rpm (in P or N) for 1 minute.
26. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P16BC indicated?
YES -
Check for poor connections or loose terminals at the alternator and the PCM, then go to step 1.
NO -
Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.�
27. Reconnect all connectors.
28. Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM.
29. Start the engine.
30. Check under these conditions:
- A/C on
- Temperature control at maximum cool
- Blower fan at maximum speed
- Rear window defogger on
- Headlights on high beam
31. Hold the engine speed at 2,000 rpm (in P or N) for 1 minute.
32. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P16BC indicated?
YES -
Check for poor connections or loose terminals at the alternator and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 29. If the PCM was substituted, go to step 1.
NO -
If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM Service and Repair. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.�