Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DLC Circuit Troubleshooting
- If the ECM does not communicate with the HDS, do this troubleshooting procedure.
- Check that the MIL circuit is normal, then do this troubleshooting.
- Measure voltage between DLC terminal No. 16 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
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.
- Measure voltage between DLC terminals No. 4 and No. 16.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there battery voltage?
- YES - Go to step 3.
- NO - Repair open in the wire between DLC terminal No. 4 and body ground.
- Measure voltage between DLC terminals No. 5 and No. 16.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there battery voltage?
- YES - Go to step 4.
- NO - Repair open in the wire between DLC terminal No. 5 and body ground.
- Turn the ignition switch ON (II).
- Measure voltage between DLC terminals No. 5 and No. 7.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there 8.5 V or more?
- YES - Go to step 10.
- NO - Go to step 6.
- Turn the ignition switch OFF, and wait for 10 seconds.
- Disconnect ECM connector A (32P).
- Check for continuity between DLC terminal No. 7 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
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 HDS, and go to the indicated DTC TROUBLESHOOTING .
- NO - Go to step 9.
- Check for continuity between DLC terminal No. 7 and ECM terminal A21.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
- YES - Update the ECM if it does not have the latest software, or substitute a known-good ECM; 2000-2001 M/T models (see HOW TO SUBSTITUTE THE ECM FOR TESTING PURPOSES (2000-2001 M/T MODELS) ), 2002-2006 M/T models and CVT model (see ECM UPDATING AND SUBSTITUTION FOR TESTING-2002-2006 M/T MODELS AND CVT MODEL ), then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM (see ECM REPLACEMENT ).
- NO - Repair open in the wire between DLC terminal No. 7 and the ECM (A21). After repairing the wire, check the DTC with the HDS, and go to the indicated DTC TROUBLESHOOTING .
- Turn the ignition switch OFF, and wait for 10 seconds.
- Disconnect ECM connector A (32P).
- Turn the ignition switch ON (II).
- Measure voltage between DLC terminals No. 5 and No. 7.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there 0 V?
- YES - Update the ECM if it does not have the latest software, or substitute a known-good ECM; 2000-2001 M/T models (see HOW TO SUBSTITUTE THE ECM FOR TESTING PURPOSES (2000-2001 M/T MODELS) ), 2002-2006 M/T models and CVT model (see ECM UPDATING AND SUBSTITUTION FOR TESTING-2002-2006 M/T MODELS AND CVT MODEL ), then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM (see ECM REPLACEMENT ).
- NO - Repair short to power in the wire between DLC terminal No. 7 and the ECM (A21). After repairing the wire, check for DTCs with the HDS, and go to the indicated DTC TROUBLESHOOTING .
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.
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