P1448

DTC P1448 (63): Intelligent Power Unit (IPU) Module Fan Problem
1. Turn the ignition switch ON (II).
2. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1634 indicated?
YES - Do the troubleshooting for DTC P1634.
NO - Go to step 3.

3. Reset the MCM.
4. Do the IPU MODULE FAN DRIVE in the INSPECTION MENU with the HDS.
Does the screen indicate OUT OF RANGE?
YES - Go to step 5.
NO - If the screen indicates CONDITION IS NORMAL, intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the IPU module fan and the MCM.

5. Turn the ignition switch OFF.
6. Turn the battery module switch OFF.
7. Remove the IPU lid.
8. Disconnect the IPU module fan 4P connector.
9. Connect IPU module fan 4P connector terminal No. 3 to body ground with a jumper wire.





10. Disconnect MCM connector B (24P).
11. Check for continuity between MCM connector terminal B11 and body ground.





Is there continuity?
YES - Go to step 12.
NO - Repair open in the wire between the IPU module fan and the MCM (B11), then go to step 23.

12. Disconnect the jumper wire.
13. Check for continuity between MCM connector terminal B20 and body ground.





Is there continuity?
YES - Repair short in the wire between the IPU module fan and the MCM (B20), then go to step 23.
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 MCM connector terminal B20 and body ground.





Is there continuity?
YES - Go to step 16.
NO - Repair open in the wire between the IPU module fan and the MCM (B20), then go to step 23.

16. Disconnect the jumper wire.
17. Check for continuity between IPU module fan 4P connector terminal No. 4 and body ground.





Is there continuity?
YES - Go to step 18.
NO - Repair open in the wire between the IPU modulator and G655, then go to step 23.

18. Reconnect MCM connector B (24P).
19. Turn the ignition switch ON (II).
20. Measure voltage between IPU module fan 4P connector terminal No. 1 and body ground.





Is there battery voltage?
YES - Go to step 21.
NO - Repair open in the wire between the IPU module fan and MCM relay 2, then go to step 22.

21. Connect IPU module fan 4P connector terminals No. 2 and No. 3 with a jumper wire.





22. Do the IPU MODULE FAN DRIVE in the INSPECTION MENU with the HDS.
Does the screen indicate OUT OF RANGE?
YES - Go to step 29.
NO - It screen indicates CONDITION is NORMAL, replace the IPU module fan, then go to step 23.

23. Turn the ignition switch OFF.
24. Reconnect all connectors.
25. Reinstall the IPU lid, then turn the battery module switch ON.
26. Turn the ignition switch ON (II).
27. Reset the MCM.
28. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
YES - If DTC P1448 is indicated, check for poor connections or loose terminals at the IPU module fan 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.

29. Reinstall the IPU lid, then turn the battery module switch ON.
30. Update the MCM if it does not have the latest software, or substitute a known-good MCM.
31. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
YES - If DTC P1448 is indicated, check for poor connections or loose terminals at the IPU module fan 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.