Data Link Connector: Testing and Inspection
DLC Circuit TroubleshootingIf the ECM does not communicate with the HDS or a scan tool, or I/M test equipment, do this troubleshooting procedure.
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 (7.5 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 body ground.
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 ECM (A23, A24) and body ground.
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 10.
NO - Go to step 6.
6. Turn the ignition switch OFF.
7. Disconnect ECM connector E (31P). Make sure the HDS or a scan tool is disconnected from the DLC.
8. 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 ECM (E23). After repairing the wire, check the DTC with the HDS or a scan tool, and go to the indicated DTC's troubleshooting.
NO - Go to step 9.
9. Check for continuity between DLC terminal No.7 and ECM terminal E23.
Is there continuity?
YES - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
NO - Repair open in the wire between DLC terminal No.7 and the ECM (E23). After repairing the wire, check the DTC with the HDS or a scan tool, and go to the indicated DTC's troubleshooting.
10. Turn the ignition switch OFF.
11. Disconnect ECM connector E (31P) Make sure the HDS or a scan tool is disconnected from the DLC.
12. Turn the ignition switch ON (II).
13. Measure voltage between DLC terminals No.5 and No.7.
Is there 0 V?
YES - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
NO - Repair short to power in the wire between the DLC terminal No.7 and the ECM (E23). After repairing the wire, check the DTC with the HDS or a scan tool, and go to the indicated DTC's troubleshooting.