DLC Circuit Troubleshooting

NOTE:

If the ECM/PCM does not communicate with the HDS, do this troubleshooting procedure.
Check that MIL circuit is normal, then do this troubleshooting.

Measure voltage between DLC terminal No. 16 and body ground.

Fig 1: Measuring Voltage Between DLC Terminal 16 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - Go to step 2.
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.
Measure voltage between DLC terminals No. 4 and No. 16.

Fig 2: Measuring Voltage Between DLC Terminals 4 And 16
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - Go to step 3.
2. NO - Repair open in the wire between DLC terminal No. 4 and body ground (G451).
Measure voltage between DLC terminals No. 5 and No. 16.

Fig 3: Measuring Voltage Between DLC Terminals 5 And 16
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - Go to step 4.
2. NO - Repair open in the wire between the ECM/PCM (E3) and DLC terminal No. 5.
Turn the ignition switch ON (II).
Measure voltage between DLC terminals No. 5 and No. 7.

Fig 4: Measuring Voltage Between DLC Terminals 5 And 7
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there 8.5 V or more?
1. YES - Go to step 11.
2. NO - Go to step 6.
Turn the ignition switch OFF.
Jump the SCS line with the HDS.
Disconnect ECM/PCM connector E (31P).
Check for continuity between DLC terminal No. 7 and body ground.

Fig 5: Checking Continuity Between DLC Terminal 7 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. 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, and go to the indicated DTC's troubleshooting.
2. NO - Go to step 10.
Check for continuity between DLC terminal No. 7 and ECM/PCM terminal E23.

Fig 6: Checking Continuity Between DLC Terminal 7 And ECM/PCM Terminal E23
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM (see ECM/PCM UPDATING AND SUBSTITUTION FOR TESTING ), then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ).
2. 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, and go to the indicated DTC's troubleshooting.
Turn the ignition switch OFF.
Jump the SCS line with the HDS.
Disconnect ECM/PCM connector E (31P).
Turn the ignition switch ON (II).
Measure voltage between DLC terminals No. 5 and No. 7.

Fig 7: Measuring Voltage Between DLC Terminals 5 & 7
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there about 0 V?
1. YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM (see ECM/PCM UPDATING AND SUBSTITUTION FOR TESTING ), then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ).
2. NO - Repair short to power in the wire between DLC terminal No. 7 and the ECM/PCM (E23). After repairing the wire, check for Temporary DTCs or DTCs with the HDS, and go to the indicated DTC's troubleshooting.