P0562 (94)
DTC PO562 (94): MCM System Low VoltageNOTE:
- To verify this is the appropriate troubleshooting procedure, jump the SCS with the HDS and read the flash code, or change the HDS setup to show HM codes and read the HM code.
- Before you troubleshoot, record all freeze data, and review the general troubleshooting information.
1. Inspect the No. 23 BACK UP (10 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
YES - Go to step 2.
NO - Go to step 9.
2. Turn the ignition switch ON (11).
3. Check the MCM BACK UP VOLTAGE in the DATA LIST with the HDS.
Is there less than 4.0 V?
YES - Go to step 4.
NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the No. 23 BACK UP (10 A) fuse and the MCM.
4. Turn the ignition switch OFF.
5. Turn the battery module switch OFF.
6. Remove the IPU lid.
7. Disconnect the MCM 20P connector.
8. Measure voltage between body ground and MCM 20P connector terminal No. 17.
Is there 12 V battery voltage?
YES - Go to step 19.
NO - Repair open in the wire between the No. 23 BACK UP (10 A) fuse and the MCM (No. 17) then go to step 13.
9. Turn the battery module switch OFF.
10. Remove the IPU lid.
11. Disconnect the MCM 20P connector.
12. Check for continuity between body ground and MCM 20P connector terminal No. 17.
Is there continuity?
YES - Repair short in the wire between the No. 23 BACK UP (10 A) fuse and the MCM (No. 17) and replace the No. 23 BACK UP (10 A) fuse. Then go to step 13.
NO - Go to step 20.
13. Reconnect all connectors.
14. Reinstall the IPU lid, then turn the battery module switch ON.
15. Turn the ignition switch ON (II).
16. Clear the DTC with the HDS.
17. Check for Temporary DTCs or DTCs with the HDS.
Is DTC PO562 (94) indicated?
YES - Check for poor connections or loose terminals at the No. 23 BACK UP (10 A) fuse and the MCM, then go to step 1.
NO - Go to step 18.
18. Monitor the OBD STATUS for DTC PO562 (94) in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in step 17, go to the indicated DTC's troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the No. 23 BACK UP (10 A) fuse and the MCM, then go to step 1. If the screen indicates NOT COMPLETED, keep the ignition switch ON (II) until a result comes on.
19. Turn the ignition switch OFF.
20. Reconnect all connectors.
21. Reinstall the IPU lid, then turn the battery module switch ON.
22. Update the MCM if it does not have the latest software, or substitute a known-good MCM.
23. Check for Temporary DTCs or DTCs with the HDS.
Is DTC PO562 (94) indicated?
YES - Check for poor connections or loose terminals at the No. 23 BACK UP (10 A) fuse and the MCM. If the MCM was updated, substitute a known-good MCM, then recheck. If the MCM was substituted, go to step 1.
NO - Go to step 24.
24. Monitor the OBD STATUS for DTC PO562 (94) in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - If the MCM was updated, troubleshooting is complete. If the MCM was substituted, replace the original MCM. If any other Temporary DTCs or DTCs were indicated in step 23, go to the indicated DTC's troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the No. 23 BACK UP (10 A) fuse and the MCM. If the MCM was updated, substitute a known-good MCM, then recheck. If the MCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep the ignition switch ON (II) until a result comes on.