P1448

DTC P1448 (63): IPU Module Fan Problem
1. Turn the ignition switch ON (II).
Is DTC P1634 indicated?
YES - Do the troubleshooting for DTC P1634.
NO - Go to step 3.
2. Reset the MCM.
3. Turn the ignition switch ON (II).
4. Start the engine, and hold the engine at 4,000 rpm for 1 minute.
5. Check for DTC P1448.
Is DTC P144S indicated?
YES - Go to step 6.
NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the IPU module fan and at the MCM.
6. Check that the IPU module fan rotates freely.
Does the IPU module fan rotate freely?
YES - Go to step 7.
NO - Repair or replace the IPU module fan.





7. Check for continuity between body ground and IPU module fan 4P connector terminal No. 4.
Is there continuity?
YES - Go to step 8.
NO - Repair open in the wire between the IPU module fan and G601.
8. Turn the ignition switch ON (II).





9. Measure voltage between body ground and IPU module fan 4P connector terminal No. 1.
Is there battery voltage?
YES - Go to step 10.
NO - Repair open in the wire between the IPU module fan and the MCM relay 2.
10. Turn the ignition switch OFF.
11. Turn the battery module switch OFF, and wait 5 minutes.
12. Remove the IPU lid, and make sure there is 30 V or less at the junction terminals.
13. Disconnect MCM connector A (31P).
14. Disconnect the IPU module fan 4P connector.





15. Check for continuity between body ground and MCM connector terminal A12.
Is there continuity?
YES - Repair short in the wire between the IPU module fan and the MCM (A12).
NO - Go to step 16.





16. Connect IPU module fan 4P connector terminal No. 3 to body ground with a jumper wire.





17. Check for continuity between body ground and MCM connector terminal A12.
Is there continuity?
YES - Go to step 18.
NO - Repair open in the wire between the IPU module fan and the MCM (A12).





18. Check for continuity between body ground and MCM connector terminal A15.
Is there continuity?
YES - Repair short in the wire between the IPU module fan and the MCM (A15).
NO - Go to step 19.





19. Connect IPU module fan 4P connector terminal No. 2 to body ground with a jumper wire





20. Check for continuity between body ground and MCM connector terminal A15.
Is there continuity?
YES - Go to step 21.
NO - Repair open in the wire between the IPU module fan and the MCM (A15).
21. Substitute a known-good IPU module fan.
22. Start the engine, and hold the engine at 4,000 rpm for 1 minute.
23. Check for DTC P1448.
Is DTC P1448 indicated?
YES - Update the MCM if it does not have the latest software, or substitute a known-good MCM, then recheck. If the symptom/indication goes away with a known-good MCM, replace the original MCM.
NO - Replace the IPU module fan.