Data Link Connector: Testing and Inspection

DLC Circuit Troubleshooting

- If the ECM does not communicate with the OBD II scan tool/Honda PGM Tester, or I/M test equipment, do this troubleshooting procedure.
- Check that MIL circuit is normal, then do this troubleshooting.




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.18 (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 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 A (32P).




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 (A21). After repairing the wire, check the DTC with the OBD II scan tool/Honda PGM Tester and go to the DTC Troubleshooting index. Diagnostic Trouble Code Descriptions

NO - Go to step 9.




9. Check for continuity between DLC terminal No.7 and ECM terminal A21.

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 (A21). After repairing the wire, check the DTC with the OBD II scan tool/Honda PGM Tester and go to the DTC Troubleshooting index. Diagnostic Trouble Code Descriptions

10. Turn the ignition switch OFF.
11. Disconnect ECM connector A (32P).
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 (A21). After repairing the wire, check the DTC with the OBD II scan tool/Honda PGM Tester and go to the DTC Troubleshooting index. Diagnostic Trouble Code Descriptions