DLC Circuit Troubleshooting

WARNING: This page is about a different car, the 2006 Acura MDX, 2005 Acura MDX, 2004 Acura MDX, and 2003 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

If the PCM does not communicate with the HDS, or I/M test equipment, 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. 46 ACGS (15 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 (G401).
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 DLC terminal No. 5 and body ground (G101).
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 12.
2. NO - Go to step 6.
Turn the ignition switch OFF.
Jump the SCS line with the HDS.
Disconnect PCM connector B (56P).
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 PCM (B17). 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.
Connect DLC terminal No. 7 to body ground with a jumper wire.

Fig 6: Connecting DLC Terminal 7 To Body Ground With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Check for continuity between PCM connector terminal B17 and body ground.

Fig 7: Checking Continuity Between PCM Connector Terminal B17 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Update the PCM if it does not have the latest software, or substitute a known-good PCM (see PCM UPDATING AND SUBSTITUTION FOR TESTING ), then recheck. If the symptom/ indication goes away with a known-good PCM, replace the original PCM (see PCM REPLACEMENT ).
2. NO - Repair open in the wire between DLC terminal No. 7 and the PCM (B17). 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 PCM connector B (56P).
Turn the ignition switch ON (II).
Measure voltage between DLC terminals No. 4 and No. 7.

Fig 8: Measuring Voltage Between DLC Terminals 4 And 7
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there 0V?
1. YES - Update the PCM if it does not have the latest software, or substitute a known-good PCM (see page 11-6), then recheck. If the symptom/ indication goes away with a known-good PCM, replace the original PCM (see PCM REPLACEMENT ).
2. NO - Repair short to power in the wire between DLC terminal No. 7 and the PCM (B17). After repairing the wire, check for a DTC with the HDS, and go to the indicated DTC's troubleshooting.