Data Link Connector: Testing and Inspection

2005 Honda Accord L4-2.4LSECTION Testing and Inspection
DLC Circuit Troubleshooting

NOTE:
- If the ECM/PCM does not communicate with the HDS, do this troubleshooting procedure.
- Check that the 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.8 FI ECU (15 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 (G501).




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. Sand body ground (G503).

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 11.

NO - Go to step 6.

6. Turn the ignition switch OFF.
7. Jump the SCS line with the HDS.
8. Disconnect ECM/PCM connector E (31P).




9. 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/PCM (E23). After repairing the wire, check for a DTC with the HDS, then go to the indicated DTC's troubleshooting.

NO - Go to step 10.




10. Check for continuity between DLC terminal No.7 and ECM/PCM terminal E23.

Is there continuity?

YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.

NO - Repair open in the wire between DLC terminal No.7 and the ECM/PCM (E23). After repairing the wire, check for a DTC with the HDS, then go to the indicated DTC's troubleshooting.

11. Turn the ignition switch OFF.
12. Jump the SCS line with the HDS.
13. Disconnect ECM/PCM connector E (31P).
14. Turn the ignition switch ON (II).




15. Measure voltage between DLC terminals No.5 and No.7.

Is there 0 V?

YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.

NO - Repair short to power in the wire between DLC terminal No.7 and the ECM/PCM (E23). After repairing the wire, check for a DTC with the HDS, then go to the indicated DTC's troubleshooting.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.