Skip to main content
DLC Circuit Troubleshooting

NOTE: Make sure the HDS and its DLC cable are working properly.
  1. Turn the ignition switch to LOCK (0).
  1. NOTE: Make sure the HDS is properly connected to the DLC.
  1. Turn the ignition switch to ON (II), and read the HDS.
Does the HDS identify the vehicle?
YES -
Go to Step 4 .
NO -
Go to Step 21 .
  1. Check for Temporary DTCs or DTCs in the PGM-FI system with the HDS.
Are any Temporary DTCs or DTCs indicated?
YES -
Go to the indicated DTC's troubleshooting.■
NO -
  • If the HDS does not communicate with the SRS system, go to Step 5 .
  • If the HDS does not communicate with the ABS system, go to Step 7 .
  • If the HDS does not communicate with the EPS system, go to Step 9 .
  • If the HDS does not communicate with the IMMOBI (immobilizer) system, go to Step 11 .
  • If the HDS does not communicate with the BODY ELECTRICAL system, go to Step 13 .
  1. Turn the ignition switch to LOCK (0).
  1. Turn the ignition switch to ON (II), and watch the SRS indicator.
Does the SRS indicator stay on?
YES -
NO -
Go to Step 13 .
  1. Turn the ignition switch to LOCK (0).
  1. Turn the ignition switch to ON (II), and watch the ABS indicator.
Does the ABS indicator stay on?
YES -
NO -
Go to Step 13 .
  1. Turn the ignition switch to LOCK (0).
  1. Turn the ignition switch to ON (II), and watch the EPS indicator.
Does the EPS indicator stay on?
YES -
NO -
Go to Step 13 .
  1. Turn the ignition switch to LOCK (0).
  1. Turn the ignition switch to ON (II), and watch the immobilizer indicator.
Does the immobilizer indicator stay on or flash?
YES -
NO -
Go to Step 13 .
  1. Check the gauge display.
Is Error 2 indicated?
YES -
Check for B-CAN system DTCs.■
NO -
Go to Step 15 .
  1. Turn the ignition switch to LOCK (0).
  1. Disconnect the HDS from the DLC.
  1. Check for continuity between DLC terminal No. 7 and body ground.
Is there 5 Ω or less?
YES -
Go to Step 18 .
NO -
Go to Step 19 .
  1. Continue to check for continuity between DLC terminal No. 7 and body ground, while disconnecting these parts, one at a time:
    • SRS unit connector A (39P)
    • ABS modulator-control unit 25P connector
    • EPS control unit connector C (16P)
    • Immobilizer-keyless control unit 7P connector
    • Audio unit 24P connector
    • Under-dash fuse/relay box connector Q (16P)
Does continuity go away when one of the above components is disconnected?
YES -
Replace the part caused an open when it was disconnected.■
NO -
Repair short in the wire between the DLC (K-line) and the ABS control unit, the SRS unit, the EPS control unit, the immobilizer-keyless control unit, the audio unit, the under-dash fuse/relay box, or the ECM/PCM.■

  1. Connect DLC terminal No. 7 to body ground with a jumper wire.
  1. Check for continuity between body ground and these connector terminals:
    Connector
    Terminal
    SRS unit A (39P)
    No. 18 (BLU)
    ABS control unit 25P
    No. 10 (BLU)
    EPS control unit C (16P)
    No. 16 (BLU)
    Immobilizer-keyless control unit 7P
    No. 5 (BLU)
    Audio unit 24P
    No. 3 (BLU)
    Under-dash fuse/relay box Q (16P)
    No. 2 (BLU)

Is there continuity between the DLC terminal and each of the terminals in the chart?
YES -
Replace the part that does not communicate with the HDS.■
NO -
Repair open in the wire between the DLC (K-line) and the appropriate connector.■
Is DTC U0029 and/or U0100 indicated?
YES -
Go to Step 34 .
NO -
Go to Step 22 .
  1. Turn the ignition switch to LOCK (0).
  1. Disconnect the HDS from the DLC.

  1. Measure the voltage between DLC terminal No. 16 and body ground.
Is there battery voltage?
YES -
Go to Step 25 .
NO -
Repair open in the wire between DLC terminal No. 16 and the No. 1 BACK UP (7.5 A) fuse in the under-dash fuse/relay box.■

  1. Measure the voltage between DLC terminals No. 4 and No. 16.
Is there battery voltage?
YES -
Go to Step 26 .
NO -
Repair open in the wire between DLC terminal No. 4 and body ground (G502).■
  1. Jump the SCS line with the HDS.
  1. Disconnect ECM/PCM connector A (49P).
  1. Disconnect the HDS from the DLC.

  1. Connect DLC terminal No. 6 to body ground with a jumper wire.

  1. Check for continuity between ECM/PCM connector terminal A3 and body ground.
Is there continuity?
YES -
Go to Step 32 .
NO -
Repair open in the wire between the ECM/PCM (A3) and DLC terminal No. 6.■

  1. Connect DLC terminal No. 14 to body ground with a jumper wire.

  1. Check for continuity between ECM/PCM connector terminal A4 and body ground.
Is there continuity?
YES -
NO -
Repair open in the wire between the ECM/PCM (A4) and DLC terminal No. 14.■
  1. Try to start the engine.
Does the engine start and idle smoothly?
YES -
NO -
Go to Step 35 .
  1. Turn the ignition switch to LOCK (0).
  1. Check the No. 60 IGSW (50 A) fuse in the under-dash fuse/relay box.
Is the fuse OK?
YES -
Repair open in the wire the No. 60 IGSW (50 A) fuse and the ignition switch. If the wire is OK go to Step 37 .
NO -
Repair short in the wire the No. 60 IGSW (50 A) fuse and the under-dash fuse/relay box. Also replace the No. 60 IGSW (50 A) fuse.■
  1. Inspect the No. 39 IGP (15 A) fuse in the under-dash fuse/relay box.
Is the fuse OK?
YES -
Go to Step 44 .
NO -
Go to Step 38 .
  1. Remove the blown No. 39 IGP (15 A) fuse from the under-dash fuse/relay box.

  1. Open the fuse lid (A), then remove the PGM-FI main relay 1 (B) from the under-dash fuse/relay box.

  1. Check for continuity between body ground and PGM-FI main relay 1 4P connector terminals No. 2 and No. 3 individually.
Is there continuity?
YES -
NO -
Go to Step 41 .

  1. While disconnecting each of the parts or connectors below, one at a time, check for continuity between PGM-FI main relay 1 4P connector terminal No. 1 and body ground.
    • PGM-FI main relay 2
    • ECM/PCM connector A (49P)
    • Each injector 2P connector
    • Camshaft position (CMP) sensor 3P connector
    • Crankshaft position (CKP) sensor 3P connector
    • Electronic throttle control system (ETCS) control relay
Does continuity go away when one of the above components is disconnected?
YES -
Replace the part that made the short to body ground go away when disconnected. If the part is the ECM/PCM, 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. Also replace the No. 39 IGP (15 A) fuse.■
NO -
Go to Step 42 .
  1. Disconnect these parts or connectors:
    • PGM-FI main relay 2
    • ECM/PCM connector A
    • Injectors
    • Camshaft position (CMP) sensor
    • Crankshaft position (CKP) sensor
    • Electronic throttle control system (ETCS) control relay

  1. Check for continuity between PGM-FI main relay 1 4P connector terminal No. 1 and body ground.
Is there continuity?
YES -
Repair short in the wire between PGM-FI main relay 1 and each item. Also replace the No. 39 IGP (15 A) fuse.■
NO -
Replace PGM-FI main relay 1. Also replace the No. 39 IGP (15 A) fuse.■
  1. Inspect the No. 20 FUEL PUMP (15 A) fuse in the under-dash fuse/relay box.
Is the fuse OK?
YES -
Go to Step 54 .
NO -
Go to Step 45 .
  1. Remove the blown No. 20 FUEL PUMP (15 A) fuse from the under-dash fuse/relay box.

  1. Open the fuse lid (A), then remove the PGM-FI main relay 2 (B) from the under-dash fuse/relay box.
Is the fuse OK?
YES -
Go to Step 48 .
NO -
Replace PGM-FI main relay 2. Also replace the No. 20 FUEL PUMP (15 A) fuse.■

  1. Check for continuity between PGM-FI main relay 2 4P connector terminal No. 2 and body ground.
Is there continuity?
YES -
Go to Step 49 .
NO -
Go to Step 52 .
  1. Jump the SCS line with the HDS.
  1. Disconnect ECM/PCM connector C (49P).

  1. Check for continuity between ECM/PCM connector terminal C10 and body ground.
Is there continuity?
YES -
Repair short in the wire between the No. 20 FUEL PUMP (15 A) fuse and the ECM/PCM (C10), or PGM-FI main relay 2. Also replace the No. 20 FUEL PUMP (15 A) fuse.■
NO -
Go to Step 52 .

  1. Check for continuity between fuel pump 4P connector terminal No. 2 and body ground.
Is there continuity?
YES -
Repair short in the wire between the fuel pump and PGM-FI main relay 2. Also replace the No. 20 FUEL PUMP (15 A) fuse.■
NO -
Check the fuel pump, and replace it if necessary. Also replace the No. 20 FUEL PUMP (15 A) fuse.■
  1. Jump the SCS line with the HDS.
  1. Disconnect ECM/PCM connectors A (49P) and C (49P).
  1. Turn the ignition switch to ON (II).

  1. Measure the voltage between ECM/PCM connector terminal C10 and body ground.
Is there battery voltage?
YES -
Go to Step 58 .
NO -
Repair open in the wire between the No. 20 FUEL PUMP (15 A) fuse and the ECM/PCM (C10).■

  1. Measure the voltage between ECM/PCM connector terminal A7 and body ground.
Is there battery voltage?
YES -
Go to Step 64 .
NO -
Go to Step 59 .
  1. Turn the ignition switch to LOCK (0).

  1. Open the fuse lid (A), then remove the PGM-FI main relay 1 (B) from the under-dash fuse/relay box.

  1. Measure the voltage between PGM-FI main relay 1 4P connector terminal No. 3 and body ground.
Is there battery voltage?
YES -
Go to Step 62 .
NO -

  1. Connect PGM-FI main relay 1 4P connector terminal No. 4 to body ground with a jumper wire.

  1. Check for continuity between ECM/PCM connector terminal A7 and body ground.
Is there battery voltage?
YES -
NO -
Repair open in the wire between the ECM/PCM (A7) and PGM-FI main relay 1.■
  1. Turn the ignition switch to LOCK (0).

  1. Open the fuse lid (A), then remove the PGM-FI main relay 1 (B) from the under-dash fuse/relay box.

  1. Measure the voltage between PGM-FI main relay 1 4P connector terminal No. 2 and body ground.
Is there battery voltage?
YES -
Go to Step 67 .
NO -

  1. Connect PGM-FI main relay 1 4P connector terminal No. 1 to body ground with a jumper wire.

  1. Check for continuity between ECM/PCM connector terminal A9 and body ground.
Is there continuity?
YES -
Go to Step 69 .
NO -
Repair open in the wire between the ECM/PCM (A9) and PGM-FI main relay 1.■
Is PGM-FI main relay 1 OK?
YES -
Go to Step 70 .
NO -
Replace the PGM-FI main relay 1 .■
  1. Disconnect ECM/PCM connector B (49P).

  1. Check for continuity between body ground and ECM/PCM connector terminals B1, B10, C2, C44, and C48 individually.
Is there continuity?
YES -
Go to Step 72 .
NO -
Repair open in the wire between the ECM/PCM (B1, B10, C2, C44, C48) and G101.■

  1. Check for continuity between ECM/PCM connector terminal C13 and body ground.
Is there continuity?
YES -
Go to Step 73 .
NO -
Go to Step 74 .
  1. Continue to check for continuity between ECM/PCM connector terminal C13 and body ground, while disconnecting these parts, one at a time:
    • MAP sensor 3P connector
    • Output shaft (countershaft) speed sensor 3P connector
Does continuity go away when one of the above components is disconnected?
YES -
Repair the part that caused an open when it was disconnected.■
NO -
Repair short in the between the ECM/PCM (C13) and the MAP sensor or the output shaft (countershaft) speed sensor.■

  1. Check for continuity between ECM/PCM connector terminal B19 and body ground.
Is there continuity?
YES -
Go to Step 75 .
NO -
Go to Step 76 .
  1. Continue to check for continuity between ECM/PCM connector terminal B19 and body ground, while disconnecting the input shaft (mainshaft) speed sensor 3P connector.
Is there continuity?
YES -
Repair short in the wire between the ECM/PCM (B19) and the input shaft (mainshaft) speed sensor.■
NO -

  1. Check for continuity between ECM/PCM connector terminal C12 and body ground.
Is there continuity?
YES -
Go to Step 77 .
NO -
Go to Step 78 .
  1. Continue to check for continuity between ECM/PCM connector terminal C12 and body ground, while disconnecting the throttle body 6P connector.
Is there continuity?
YES -
Repair short in the wire between the ECM/PCM (C12) and the throttle body.■
NO -

  1. Check for continuity between ECM/PCM connector terminal A26 and body ground.
Is there continuity?
YES -
Go to Step 79 .
NO -
Go to Step 80 .
  1. Continue to check for continuity between ECM/PCM connector terminal A26 and body ground, while disconnecting the APP sensor 6P connector.
Is there continuity?
YES -
Repair short in the wire between the ECM/PCM (A26) and APP sensor A.■
NO -

  1. Check for continuity between ECM/PCM connector terminal A25 and body ground.
Is there continuity?
YES -
Go to Step 81 .
NO -
  1. Continue to check for continuity between ECM/PCM connector terminal A25 and body ground, while disconnecting the APP sensor 6P connector.
Is there continuity?
YES -
Repair short in the wire between the ECM/PCM (A25) and APP sensor B.■
NO -