P1448

DTC P1448 (63): IPU Module Fan Problem
1. Reset the MCM.
2. Turn the ignition switch ON (II).
Is DTC P1634 indicated?
YES-Do the troubleshooting procedure for DTC P1634.
NO-Go to step 3.
3. Reset the MCM.
4. Start the engine, and hold it at 3,000 - 4,000 rpm for 2 minutes.
Is DTC P1448 indicated?
YES-Go to step 5.
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.
5. Turn the ignition switch OFF.
6. Turn the battery module switch OFF.
7. Remove the IPU lid.
8. Disconnect MCM connector A (31P).
9. Disconnect the IPU module fan 4P connector.





10. 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 11.





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





12. Check for continuity between body ground and MCM connector terminal A12.
Is there continuity?
YES-Go to step 13.
NO-Repair open in the wire between the IPU module fan and the MCM (A12).





13. 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 end the MCM (A15).
NO-Go to step 14.





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





15. Check for continuity between body ground and MCM connector terminal A15.
Is there continuity?
YES-Go to step 16.
NO-Repair open in the wire between the IPU module fan and the MCM





16. Check for continuity between body ground and IPU module fan 4P connector terminal No. 4.
Is there continuity?
YES-Go to step 17.
NO-Repair open in the wire between the IPU module fan and G601.
17. Reconnect MCM connector A (31P).
18. Turn the ignition switch ON (II).





19. Measure voltage between body ground and IPU module fan 4P connector terminal No. 1.
Is there battery voltage?
YES-Go to step 20.
NO-Repair open in the wire between the IPU module fan and MCM relay 2.
20. Turn the ignition switch OFF.
21. Reconnect the IPU module fan 4P connector.
22. Start the engine, send hold it at 3,500 - 4,000 rpm for 1 minute.
Does the IPU module fan run?
YES-Go to step 23.
NO-Go to step 27.
23. Turn the ignition switch OFF.





24. Connect IPU module fan 4P connector terminal No. 2 to body ground with a jumper wire.
25. Turn the ignition switch ON (II).





26. Measure voltage between body ground and MCM connector terminal A15.
Is there more than 2 V?
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.
27. Turn the ignition switch OFF.
28. Disconnect the IPU module fan 4P connector.





29. Start the engine, and hold it at 3,500 - 4,000 rpm for 1 minute.
30. Measure voltage between body ground and MCM connector terminal A12.
Is there more than 2 V?
YES-Replace the IPU module fan.
NO-Update the MCM if it does not have the latest software, or substitute a known-good MCM, then recheck. If he symptom/indication goes away with a known-good MCM, replace the original MCM.