Voltage Inverter: Testing and Inspection

Motor Power Inverter (MPI) Module Fan Test

Motor Power Inverter (MPI) Module Fan Does Not Run
1. Turn the ignition switch OFF.
2. Remove the cargo floor mat.
3. Turn the battery module switch OFF.
4. Remove the IPU lid.





5. Connect MCM connector terminal A6 to body ground with a jumper wire.
Does the MPI module fan run?
YES-Go to step 6.
NO-Go to step 7.





6. Connect MCM connector terminals A6 and A7 to body ground with jumper wires.
Does the MPI module fan run at high speed?
YES-The MPI module fan is OK.
NO-Go to step 15.
7. Check the low speed MPI module fan control relay.
Is the relay OK?
YES-Go to step 8.
NO-Replace the low speed MPI module fan control relay.
8. Disconnect MCM connector A (32P) and the low speed MPI module fan control relay V connector.





9. Connect low speed MPI module fan control relay V connector terminal No. 3 to body ground with a jumper wire.





10. Check for continuity between body ground and MCM connector terminal A6.
Is there continuity?
YES-Go to step 11.
NO-Repair open in the wire between the MCM (A6) and the low speed MPI module fan control relay.





11. Measure voltage between body ground and low speed MPI module fan control relay 4P connector terminals No. 2 and No. 4 individually.
Is there battery voltage?
YES-Go to step 12.
NO-Check for:
^ A blown No. 5 IMA FAN (15 A) fuse.
^ An open in the wire between the No. 5 IMA FAN (15 A) fuse and the low speed MPI module fan control relay.
12. Disconnect the MPI module fan 2P connector.





13. Connect MPI module fan 2P connector terminal No. 1 to body ground with a jumper wire.





14. Check for continuity between body ground and low speed MPI module fan control relay V connector terminal No. 1.
Is there continuity?
YES-Substitute a known-good MCM and MPI module fan, and recheck. If the symptom/indication goes away, replace the original MCM and the MPI module fan.
NO-Repair open in the wire between the MPI module fan and the low speed MPI module fan control relay.
15. Check the high speed MPI module fan control relay.
Is the relay OK?
YES-Go to step 16.
NO-Replace the high speed MPI module fan control relay.
16. Disconnect MCM connector A (32P) and the high speed MPI module fan control relay V connector.





17. Connect high speed MPI module fan control relay 4P connector terminal No. 3 to body ground with a jumper wire.





18. Check for continuity between body ground and MCM connector terminal AT.
Is there continuity?
YES-Go to step 19.
NO-Repair open in the wire between the MCM (A7) and the high speed MPI module fan control relay.





19. Measure voltage between body ground and high speed MPI module fan control relay V connector terminal No. 4.
Is there battery voltage?
YES-Go to step 20.
NO-Check for:
^ A blown No. 5 IMA FAN (15A) fuse.
^ An open in the wire between the No. 5 IMA FAN (15 A) fuse and the high speed MPI module fan control relay.





20. Check for continuity between body ground and high speed MPI module fan control relay V connector terminal No. 1.
Is there continuity?
YES-Go to step 2 1.
NO-Repair open in the wire between G502 and the high speed MPI module fan control relay.
21. Disconnect the MPI module fan 2P connector.





22. Connect MPI module fan 2P connector terminal No. 2 to body ground with a jumper wire.





23. Check for continuity between body ground and high speed MPI module fan control relay V connector terminal No. 2.
Is there continuity?
YES-Substitute a known-good MCM and MPI module fan, and recheck. If the symptom/indication goes away, replace the original MCM and the MPI module fan.
NO-Check for:
^ An open in the wire between the MPI module fan control resistor and the high speed MPI module fan relay.
^ An open in the wire between the MPI module fan control resistor and the MPI module fan.
^ An open in the wire between the MPI module fan control resistor and G502.
^ Replace the MPI module fan control resistor.

MPI Module Fan Keeps Running, or Always Runs at High Speed

NOTE: Information marked with an asterisk applies to the PDUFANH line.

1. Turn the ignition switch OFF.
2. Remove the cargo floor mat.
3. Turn the battery module switch OFF.
4. Remove the IPU lid.
5. Disconnect MCM connector A (32P).
Does the MPI module fan run?
YES-Go to step 6.
NO-Substitute a known-good MCM and recheck. If the symptom/indication goes away, replace the original MCM.
6. Disconnect the low speed MPI module fan control relay V connector and high speed MPI module fan control relay 4P connector.





7. Check for continuity between body ground and MCM connector terminals A6 and A7
Is there continuity?
YES-Repair short in the wire between the MCM (A6, A7*) and the low (high)* speed motor MPI module fan control relay.
NO-Go to step 8.
8. Check the low (high)* speed MPI module fan control relay.
Is the relay OK?
YES-Repair short in the wire between the MPI module fan and high speed MPI module fan control relay.
NO-Replace the low (high)* speed MPI module fan control relay.