DLC Circuit Troubleshooting

DLC Circuit Troubleshooting

NOTE: Do this troubleshooting if the MCM does not communicate with the HDS or I/M test equipment.





1. Measure voltage between DLC terminal No. 16 and body ground.
Is there battery voltage?
YES-Go to step 2.
NO-Repair open in the wire between DLC terminal No. 16 and the No. 9 BACK UP (10 A) fuse in the under-hood fuse/relay box.





2. Measure voltage between DLC terminals No. 4 and No. 16.
Is there battery voltage?
YES-Go to step 3.
NO-Repair open in the wire between DLC terminal No. 4 and G504.





3. Measure voltage between DLC terminals No. 5 and No. 16.
Is there battery voltage?
YES-Go to step 4.
NO-Repair open in the wire between DLC terminal No. 5 and the ECM (E3), or between the ECM (A23, A24) and G101.
4. Turn the ignition switch ON (II).





5. Measure voltage between DLC terminals No. 5 and No. 7.
Is there 8.5 V or more?
YES-Go to step 13.
NO-Go to step 6.
6. Turn the ignition switch OFF.
7. Turn the battery module switch OFF.
8. Remove the IPU lid.
9. Disconnect MCM connector A (31P). Make sure the HDS is disconnected from the DLC.





10. Check for continuity between DLC terminal No. 7 and body ground.
Is there continuity?
YES-Repair short to ground in the wire between DLC terminal No. 7 and the MCM (A28). After repairing the wire, check for DTCs with the HDS. If there is a DTC, go to the DTC Troubleshooting.
NO-Go to step 11.





11. Connect DLC terminal No. 7 to body ground with a jumper wire.





12. Check for continuity between MCM terminal A28 and body ground.
Is there continuity?
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-Repair open in the wire between DLC terminal No. 7 and the MCM (A28). After repairing the wire, check for DTCs with the HDS. If there is a DTC, go to the DTC Troubleshooting.
13. Turn the ignition switch OFF.
14. Turn the battery module switch OFF.
15. Remove the IPU lid.
16. Disconnect MCM connector A (31P). Make sure the HDS is disconnected from the DLC.
17. Turn the ignition switch ON (II).





18. Measure voltage between DLC terminals No. 5 and No.7.
Is there 0 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-Repair short to power in the wire between DLC terminal No. 7 and the MCM (A28). After repairing the wire, check for DTCs with the HDS. If there is a DTC, go to the DTC Troubleshooting.