Manufacturer Code Charts: 47
DTC Troubleshooting: P1634 (47)
DTC P1634:
Motor Power Inverter (MPI) Module Signal Circuit Malfunction
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 the DTC cannot be cleared, do the troubleshooting for DTC U1204.
1. Turn the ignition switch to ON (II).
2. Clear the DTC with the HDS.
3. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P1634 indicated?
YES -
Go to step 4.
NO -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the MCM and the MPI module.�
4. Do the IPU MODULE FAN DRIVE in the INSPECTION MENU with the HDS.
Does the HDS indicate OUT OF RANGE?
YES -
Go to step 5.
NO -
If the HDS indicates CONDITION IS NORMAL, go to step 15.
5. Check the No. B53 B IMA 2 (15 A) fuse in the under-dash fuse/relay box.
Is the fuse OK?
YES -
Go to step 6.
NO -
Repair a short to ground in the wire between the IPU module fan or the MPI module and the No. B53 B IMA 2 (15 A) fuse. Also replace the No. B53 B IMA 2 (15 A) fuse, then go to step 39.
6. Turn the ignition switch to LOCK (0).
7. Turn the battery module switch OFF.
8. Remove the IPU cover IPU Cover Removal/Installation.
9. Turn the ignition switch to ON (II), and listen for a clicking sound from MCM relay 2 (A).
Is there a clicking sound?
YES -
Go to step 10.
NO -
Go to step 27.
10. Turn the ignition switch to LOCK (0).
11. Remove MCM relay 2 (A).
12. Test MCM relay 2.
Is the relay OK?
YES -
Go to step 13.
NO -
Replace MCM relay 2, then go to step 39.
13. Turn the ignition switch to ON (II).
14. Measure the voltage between IPU relay holder (MCM relay 2) 8P connector terminal No. 2 and body ground.
Is there battery voltage?
YES -
Repair an open in the wire between MCM relay 2 and MPI module 12P connector terminal No. 7, then go to step 39.
NO -
Repair an open in the wire between the No. B53 B IMA 2 (15 A) fuse and MCM relay 2, then go to step 39.
15. Turn the ignition switch to LOCK (0).
16. Turn the battery module switch OFF.
17. Remove the IPU cover IPU Cover Removal/Installation.
18. Remove the PCU lid, the PCU busplate, and the PCU cover Service and Repair.
19. Disconnect MCM connector C (22P).
20. Measure the resistance between MCM connector terminal C18 and body ground.
Is there 1 MOhms or more?
YES -
Go to step 21.
NO -
Go to step 36.
21. Disconnect the MPI module 12P connector (A).
22. Reconnect MCM connector C (22P).
23. Turn the ignition switch to ON (II).
24. Measure the voltage between MPI module 12P connector terminals No. 7 and No. 12.
Is there about 12 V?
YES -
Go to step 25.
NO -
Go to step 38.
25. Measure the voltage between MPI module 12P connector terminal No. 2 and body ground.
Is there about 12 V?
YES -
Replace the MPI module Service and Repair, then go to step 39.
NO -
Go to step 26.
26. Measure the voltage between MCM connector terminal C18 and body ground.
Is there about 12 V?
YES -
Repair an open in the wire between the MPI module 12P connector and the MCM (C18), then go to step 39.
NO -
Go to step 45.
27. Turn the ignition switch to LOCK (0).
28. Remove MCM relay 2 (A).
29. Test MCM relay 2.
Is the relay OK?
YES -
Go to step 30.
NO -
Replace MCM relay 2, then go to step 39.
30. Turn the ignition switch to ON (II).
31. Measure the voltage between IPU relay holder (MCM relay 2) 8P connector terminal No. 3 and body ground.
Is there about 12 V?
YES -
Go to step 32.
NO -
Repair an open in the wire between MCM relay 1 and MCM relay 2, then go to step 39.
32. Turn the ignition switch to LOCK (0).
33. Reinstall MCM relay 2 (A).
34. Turn the ignition switch to ON (II).
35. Measure the voltage between MCM connector terminal A4 and body ground.
Is there about 12 V?
YES -
Go to step 45.
NO -
Repair an open in the wire between MCM relay 2 and the MCM (A4), then go to step 39.
36. Disconnect the MPI module 12P connector (A).
37. Check for continuity between MCM connector terminal C18 and body ground.
Is there continuity?
YES -
Repair a short in the wire between the MPI module 12P connector and the MCM (C18), then go to step 39.
NO -
Replace the MPI module Service and Repair, then go to step 39.
38. Measure the voltage between MPI module 12P connector terminal No. 7 and body ground.
Is there battery voltage?
YES -
Repair an open in the wire between MPI module 12P connector terminal No. 12 and G901, then go to step 39.
NO -
Repair an open in the wire between MCM relay 2 and MPI module 12P connector terminal No. 7, then go to step 39.
39. Reconnect all connectors.
40. If removed, reinstall the PCU cover, the PCU busplate, and the PCU lid Service and Repair.
41. If removed, reinstall the IPU cover IPU Cover Removal/Installation, then turn the battery module switch ON.
42. Turn the ignition switch to ON (II).
43. Clear the DTC with the HDS.
44. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P1634 indicated?
YES -
Check for poor connections or loose terminals at the MCM and the MPI module, 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.�
45. Reconnect all connectors.
46. Reinstall the PCU cover, the PCU busplate, and the PCU lid Service and Repair.
47. Reinstall the IPU cover IPU Cover Removal/Installation, then turn the battery module switch ON.
48. Update the MCM if it does not have the latest software Testing and Inspection, or substitute a known-good MCM.
49. Turn the ignition switch to ON (II).
50. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P1634 indicated?
YES -
Check for poor connections or loose terminals at the MCM and the MPI module. If the MCM was updated, substitute a known-good MCM, then recheck. If the MCM was substituted, go to step 1.
NO -
If the MCM was updated, troubleshooting is complete. If the MCM was substituted, replace the original MCM Service and Repair. If any other Pending or Confirmed DTCs were indicated, go to the indicated DTC's troubleshooting.�