DTC 34

DTC U1220 (34): DC-DC Converter Lost Communication with BCM Module
1. Turn the ignition switch ON (II).
2. Monitor the OBD STATUS for DTC U1220 (34) in the DTCs MENU with the HDS.
Does the screen indicate FAILED?
YES - Go to step 3.
NO - If the screen indicates PASSED, intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the DC-DC converter and the BCM module. If the screen indicates NOT COMPLETED, go to step 1 and recheck.

3. Turn the ignition switch OFF.
4. Turn the battery module switch OFF.
5. Remove the IPU lid.
6. Disconnect the DC-DC converter V connector.
7. Disconnect BCM module connector A (40P).
8. Check for continuity between BCM module connector terminal A19 and body ground.





Is there continuity?
YES - Repair short in the wire between the BCM module (A19) and the DC-DC converter, then go to step 17.
NO - Go to step 9.

9. Check for continuity between BCM module connector terminal A19 and DC-DC converter 4P connector terminal No. 3.





Is there continuity?
YES - Go to step 10.
NO - Repair open in the wire between the BCM module (A19) and the DC-DC converter, then go to step 17.

10. Substitute a known-good DC-DC converter.
11. Reconnect all connectors.
12. Reinstall the IPU lid, then turn the battery module switch ON.
13. Turn the ignition switch ON (II).
14. Reset the BCM module with the HDS.
15. Check for IMA system Temporary DTCs or DTCs with the HDS.
Is DTC U1220 (34) indicated?
YES - Go to step 24.
NO - Replace the original DC-DC converter, then go to step 17.

16. Turn the ignition switch OFF.
17. Reconnect all connectors.
18. Reinstall the IPU lid, then turn the battery module switch ON.
19. Turn the ignition switch ON (II).
20. Reset the BCM module with the HDS.
21. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
YES - If DTC U1220 is indicated, check for poor connections or loose terminals at the DC-DC converter and the BCM module, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO - Go to step 22.

22. Monitor the OBD STATUS for DTC U1220 (34) in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - Troubleshooting is complete.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the DC-DC converter and the BCM module, then go to step 1. If the screen indicates NOT COMPLETED, turn the ignition switch ON (II), and wait for a result to come on.

23. Reinstall the IPU lid, then turn the battery module switch ON.
24. Update the BCM module if it does not have the latest software, or substitute a known-good BCM module.
25. Check for IMA system Temporary DTCs or DTCs with the HDS.
Is DTC U1220 (34) indicated?
YES - Check for poor connections or loose terminals at the DC-DC converter and the BCM module. If the BCM module was updated, substitute a known-good BCM module, then recheck. If the BCM module was substituted, go to step 1.
NO - If no Temporary DTCs or DTCs are indicated, go to step 26. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

26. Monitor the OBD STATUS for DTC U1220 (34) in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - If the BCM module was updated, troubleshooting is complete. If the BCM module was substituted, replace the original BCM module.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the DC-DC converter and the BCM module, then go to step 1. If the screen indicates NOT COMPLETED, go to step 1 and recheck.