IMA System
DTC Troubleshooting: U0038 (99), U1204 (55)
DTC U0038:
IMA-CAN Malfunction (BUS-OFF (Motor Control Module (MCM)))
DTC U1204:
IMA-CAN Malfunction (Powertrain Control Module (PCM) - Motor Control Module (MCM))
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information Initial Inspection and Diagnostic Overview.
1. Turn the ignition switch to ON (II).
2. Clear the DTC with the HDS.
3. Check the ENGINE COOLANT TEMPERATURE in the IMA DATA LIST with the HDS.
Is 419 °F (215 °C) indicated?
YES -
Go to step 4.
NO -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the PCM and the MCM.
4. Jump the SCS line with the HDS.
5. Turn the ignition switch to LOCK (0).
6. Disconnect PCM connector A (44P).
7. Measure the resistance between PCM connector terminals C35 and C36.
Is there about 120 Ohms?
YES -
Go to step 19.
NO -
- If there is no continuity, go to step 13.
- If there is 1 Ohms or less, go to step 8.
8. Turn the battery module switch OFF.
9. Remove the IPU cover IPU Cover Removal/Installation.
10. Remove the PCU lid, the PCU busplate, and the PCU cover Service and Repair.
11. Disconnect MCM connector A (31P).
12. Check for continuity between MCM connector terminals A8 and A9.
Is there continuity?
YES -
Repair a short in the wire between the MCM connector terminals A8 and A9, then go to step 31.
NO -
Go to step 38.
13. Turn the battery module switch OFF.
14. Remove the IPU cover IPU Cover Removal/Installation.
15. Remove the PCU lid, the PCU busplate, and the PCU cover Service and Repair.
16. Disconnect MCM connector A (31P).
17. Check for continuity between MCM connector terminal A8 and PCM connector terminal C35.
Is there continuity?
YES -
Go to step 18.
NO -
Repair an open in the wire between the PCM (C35) and the MCM (A8), then go to step 31.
18. Check for continuity between MCM connector terminal A9 and PCM connector terminal C36.
Is there continuity?
YES -
Go to step 38.
NO -
Repair an open in the wire between the PCM (C36) and the MCM (A9), then go to step 31.
19. Turn the battery module switch OFF.
20. Remove the IPU cover IPU Cover Removal/Installation.
21. Remove the PCU lid, the PCU busplate, and the PCU cover Service and Repair.
22. Disconnect MCM connector A (31P).
23. Check for continuity between MCM connector terminal A8 and body ground.
Is there continuity?
YES -
Repair a short to ground in the wire between the PCM (C35) and the MCM (A8), then go to step 31.
NO -
Go to step 24.
24. Check for continuity between MCM connector terminal A9 and body ground.
Is there continuity?
YES -
Repair a short to ground in the wire between the PCM (C36) and the MCM (A9), then go to step 31.
NO -
Go to step 25.
25. Turn the ignition switch to ON (II).
26. Measure the voltage between MCM connector terminal A8 and body ground.
Is there about 5-12 V?
YES -
Repair a short to power in the wire between the PCM (C35) and the MCM (A8), then go to step 31.
NO -
Go to step 27.
27. Measure the voltage between MCM connector terminal A9 and body ground.
Is there about 5-12 V?
YES -
Repair a short to power in the wire between the PCM (C36) and the MCM (A9), then go to step 31.
NO -
Go to step 28.
28. Turn the ignition switch to LOCK (0).
29. Reconnect PCM connector A (44P).
30. Measure the resistance between MCM connector terminals A8 and A9.
Is there about 120 Ohms?
YES -
Go to step 38.
NO -
Update the PCM if it does not have the latest software, or substitute a known-good PCM, and recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM, then go to step 31.
31. Reconnect all connectors.
32. Reinstall the PCU cover, the PCU busplate, and the PCU lid Service and Repair.
33. Reinstall the IPU cover IPU Cover Removal/Installation, then turn the battery module switch ON.
34. Turn the ignition switch to ON (II).
35. Clear the DTC with the HDS.
36. Check for Pending or Confirmed DTCs in the IMA SYSTEM with the HDS.
Is DTC U0038 or U1204 indicated?
YES -
Check for poor connections or loose terminals at the PCM and the MCM, then go to step 1.
NO -
Go to step 37.
37. Monitor the OBD STATUS for DTC U0038 or U1204 in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?
YES -
Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 36, go to the indicated DTC's troubleshooting.
NO -
If the HDS indicates FAILED, check for poor connections or loose terminals at the PCM and MCM, then go to step 1. If the HDS indicates NOT COMPLETED, keep the ignition switch ON (II) until a result comes on.
38. Reconnect all connectors.
39. Reinstall the PCU cover, the PCU busplate, and the PCU lid Service and Repair.
40. Reinstall the IPU cover IPU Cover Removal/Installation, then turn the battery module switch ON.
41. Update the MCM if it does not have the latest software Testing and Inspection, or substitute a known-good MCM.
42. Turn the ignition switch to ON (II).
43. Check for Pending or Confirmed DTCs with the HDS in the IMA SYSTEM.
Is DTC U0038 or U1204 indicated?
YES -
Check for poor connections or loose terminals at the PCM and the MCM. If the MCM was updated, substitute a known-good MCM, and recheck. If the MCM was substituted, go to step 1.
NO -
Go to step 44.
44. Monitor the OBD STATUS for DTC U0038 or U1204 in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?
YES -
If the MCM was updated, troubleshooting is complete. If the MCM was substituted, replace the original MCM Service and Repair. If any other Pending or Confirmed DTCs were indicated in step 43, go to the indicated DTC's troubleshooting.
NO -
If the HDS indicates FAILED, check for poor connections or loose terminals at the PCM and the MCM. If the MCM was updated, substitute a known-good MCM, and recheck. If the MCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, keep the ignition switch ON (II) until a result comes on.