P1634

DTC P1634 (47): Motor Power Inverter (MPI) Module Signal Circuit Malfunction
1. Turn the ignition switch ON (II).
2. Reset the MCM.
3. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1634 indicated?
YES - Go to step 4.
NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the MPI module and the MCM.

4. Turn the ignition switch OFF.
5. Turn the battery module switch OFF.
6. Remove the IPU lid.
7. Disconnect MCM connector A (31P).
8. Disconnect the MPI module 16P connector.
9. Check for continuity between MCM connector terminal A25 and body ground.





Is there continuity?
YES - Repair short in the wire between the MPI module and the MCM A25, then go to step 24.
NO - Go to step 10.

10. Check for continuity between MCM connector terminal A25 and MPI module 16P connector terminal No. 5.





Is there continuity?
YES - Go to step 11.
NO - Repair open in the wire between the MPI module and the MCM A25, then go to step 24.

11. Check for continuity between MPI module 16P connector terminal No. 6 and body ground,





Is there continuity?
YES - Go to step 12.
NO - Repair open in the wire between the MPI module and G652, then go to step 24.

12. Reconnect MCM connector A (31P).
13. Turn the ignition switch ON (II).
14. Measure voltage between MPI module 16P connector terminal No. 8 and body ground.





Is there 12 V battery voltage?
YES - Replace the MPI module, then go to step 30.
NO - Go to step 15.

15. Measure voltage between MCM relay 24P connector terminal No. 1 and body ground.





Is there 12 V battery voltage?
YES - Repair open in the wire between MCM relay 2 and the MPI module, then go to step 24.
NO - Go to step 16.

16. Check MCM relay 2.
Is the relay OK?
YES - Go to step 17.
NO - Replace MCM relay 2, then go to step 24.

17. Measure voltage between MCM relay 24P connector terminal No. 2 and body ground.





Is there 12 V battery voltage?
YES - Go to step 19.
NO - Go to step 18.

18. Check the +B IMA (10 A) fuse.
Is the fuse OK?
YES - Repair open in the wire between MCM relay 2 and the +B IMA (10 A) fuse. Then replace the +B IMA (10 A) fuse and the OPTION (40 A) fuse, and go to step 24.
NO -
^ Replace the +B IMA (10 A) fuse.
^ Repair short in the wire the +B IMA (10 A) fuse and MCM relay 2.
^ Repair open in the wire between the +B IMA (10 A) fuse and the OPTION (40 A) fuse.
^ Repair open in the wire between the 12 V battery and the OPTION (40 A) fuse.

19. Turn the ignition switch ON (II).
20. Measure voltage between MCM connector terminal B14 and body ground.





Is there 12 V battery voltage?
YES - Reinstall the IPU lid, then turn the battery module switch ON, and go to step 35.
NO - Go to step 21.

21. Turn the ignition switch OFF.
22. Disconnect MCM connector B (24P).
23. Check for continuity between MCM connector terminal B14 and MCM relay 24P connector terminal No. 3.





Is there continuity?
YES - Repair open in the wire between MCM relay 1 and MCM relay 2, then go to step 24.
NO - Repair open in the wire between MCM relay 2 and the MCM (B14), then go to step 24.

24. Turn the ignition switch OFF.
25. Reconnect all connectors.
26. Reinstall the IPU lid, then turn the battery module switch ON.
27. Turn the ignition switch ON (II).
28. Reset the MCM.
29. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
YES - If DTC P1634 is indicated, check for poor connections or loose terminals at the MPI module and the MCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO - Troubleshooting is complete.

30. Turn the ignition switch OFF.
31. Reconnect all connectors.
32. Reinstall the IPU lid, then turn the battery module switch ON.
33. Turn the ignition switch ON (II).
34. Reset the MCM.
35. Update the MCM if it does not have the latest software, or substitute a known-good MCM.
36. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
YES - If DTC P1634 is indicated, check for poor connections or loose terminals at the MPI module and the MCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO - If the MCM was updated, troubleshooting is complete. If the MCM was substituted, replace the original MCM.