DTC Troubleshooting
DTC Troubleshooting: P16BC, P16BC
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 How to Troubleshoot the Fuel and Emissions Systems.
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 connector or terminals, then go to step 18.
2. Check the alternator mounting surfaces for corrosion.
Are the mounting surfaces corroded?
YES -
Remove the alternator Removal and Replacement. Clean all mounting surfaces, reinstall the alternator, then go to step 18.
NO -
Go to step 3.
3. Turn the ignition switch to ON (II).
4. Clear the DTC with the HDS.
5. Start the engine.
6. 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
7. Hold the engine speed 2,000 rpm (A/T in P or N, M/T in neutral) for 1 minute.
8. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P16BC indicated?
YES -
Go to step 9.
NO -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the alternator.
9. Turn the ignition switch to LOCK (0).
10. Disconnect the alternator 4P connector.
11. Turn the ignition switch to ON (II).
12. Measure the voltage between alternator 4P connector terminal No. 1 and body ground.
Is there battery voltage?
YES -
Go to step 13.
NO -
Repair an open in the wire between the alternator (IG1 line) and the No. 7 ACG (15 A) fuse in the driver's under-dash fuse/relay box, then go to step 18.
13. 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 14.
14. Turn the ignition switch to LOCK (0).
15. Jump the SCS line with the HDS.
16. Disconnect ECM/PCM connector B (49P).
17. Check for continuity between alternator 4P connector terminal No. 4 and ECM/PCM connector terminal B47.
Is there continuity?
YES -
Go to step 27.
NO -
Repair an open in the wire between the ECM/PCM(B47) and the alternator, then go to step 18.
18. Turn the ignition switch to LOCK (0).
19. Reconnect all connectors.
20. Turn the ignition switch to ON (II).
21. Reset the ECM/PCM with the HDS.
22. Do the ECM/PCM idle learn procedure ECM/PCM Idle Learn Procedure (M/T).
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 2,000 rpm (A/T in P or N, M/T in neutral) 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 ECM/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 ECM/PCM if it does not have the latest software ECM/PCM Update (M/T), or substitute a known-good ECM/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 2,000 rpm (A/T in P or N, M/T in neutral) 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 ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to step 29. If the ECM/PCM was substituted, go to step 1.
NO -
If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM Service and Repair. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.