DLC Circuit Troubleshooting

NOTE: Make sure the HDS and the DLC cable of the HDS is normal.

1.Turn the ignition switch OFF.

2.Connect the HDS to the DLC.

NOTE: Make sure the HDS is properly connected to the DLC.

3.Turn the ignition switch ON (II), and read the HDS.

Does the HDS indentify the vehicle?


YES - Go to 4.


NO - Go to 23.


4.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.n


NO - Go to 5.


5.Turn the ignition switch OFF.

6.Turn the ignition switch ON (II), and watch the SRS indicator.

Does the SRS indicator stay on?


YES - Go to the SRS system's general troubleshooting information.n


NO -

  • With ABS system: Go to 7.
  • With VSA system: Go to 9.

7.Turn the ignition switch OFF.

8.Turn the ignition switch ON (II), and watch the ABS indicator.

Does the ABS indicator stay on?


YES - Go to the ABS system's general troubleshooting information.n


NO - Go to 11.


9.Turn the ignition switch OFF.

10.Turn the ignition switch ON (II), and watch the VSA indicator.n

Does the VSA indicator stay on?


YES - Go to the VSA system's general troubleshooting information.


NO - Go to 11.


11.Turn the ignition switch OFF.

12.Turn the ignition switch ON (II), and watch the EPS indicator.

Does the EPS indicator stay on?


YES - Go to the EPS system's general troubleshooting information.n


NO - Go to 13.

13.Turn the ignition switch OFF.

14.Turn the ignition switch ON (II), and watch the immobilizer indicator.

Does the immbilizer indicator stay on or flash?


YES - Go to the immobilizer system's troubleshooting.n


NO - Go to 15.


15.Do the gauge self-diagnostic function.

16.Check for B-CAN system DTCs without the HDS.

Are any B-CAN DTCs indicated?


YES - Go to the indicated DTC's troubleshooting.n


NO - Go to 17.


17.Turn the ignition switch OFF.

18.Disconnect the HDS from the DLC.

19.Check for continuity between DLC terminal No. 7 and body ground.

 

Is there 5 W or less?


YES - Go to 20.


NO - Go to 21.

20.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 (28P)
  • ABS modulator-control unit 25P connector (with ABS system)
  • VSA modulator-control unit 37P connector (with VSA system)
  • EPS control unit connector D (28P) (with electrical power steering)
  • Immobilizer-keyless control unit 7P connector
  • Audio unit 17P connector
  • Under-dash fuse/relay box (Q) (16P) connector

Does continuity go away when one of the above components is disconnected?


YES - Replace the part that caused an open when it was disconnected.n


NO - Repair short in the wire between the DLC (K-line) and the ABS modulator-control unit (with ABS system), the VSA modulator-control unit (with VSA system), the SRS unit, the EPS control unit (with electrical power steering), the immobilizer-keyless control unit, the audio unit, or the under-dash fuse/relay box.n

21.Connect DLC terminal No. 7 to body ground with a jumper wire.

 

22.Check for continuity between body ground and these connector terminals:

Connector Terminal 
SRS unit A (28P) No. 24
(LT BLU) 
ABS modulator-control unit 25P (with ABS system) No. 10
(LT BLU) 
VSA modulator-control unit 37P (with VSA system) No. 26
( LT BLU ) 
EPS control unit D (28P) No. 17
(LT BLU) 
Immobilizer-keyless control unit 7P No. 5 (LT BLU) 
Audio unit 17P No. 6 (LT BLU) 
Under-dash fuse/relay box (Q) (16P) No. 8 (LT BLU) 

Is there continuity between the DLC terminal and each of the terminals in the chart?


YES - Replace the unit which cannot communicate with the HDS.n


NO - Repair open in the wire between the DLC (K-line) and the appropriate connector.n

23.Do the gauge self-diagnostic function.

24.Check for B-CAN system DTCs without the HDS.

Is DTC B1168, B1169 and/or B1178 indicated?


YES - Go to 37.


NO - Go to 25.


25.Turn the ignition switch OFF.

26.Disconnect the HDS from the DLC.

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

 

Is there battery voltage?


YES - Go to 28.


NO - Repair open in the wire between DLC terminal No. 16 and the No. 23 BACK UP (10 A) fuse in the under-hood fuse/relay box.n

28.Measure voltage between DLC terminals No. 4 and No. 16.

 

Is there battery voltage?


YES - Go to 29.


NO - Repair open in the wire between DLC terminal No. 4 and body ground (LHD: G502, RHD: G503).n


29.Connect the HDS to the DLC.

30.Jump the SCS line with the HDS.

31.Disconnect ECM/PCM connector A (44P).

32.Disconnect the HDS from the DLC.

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

 

34.Check for continuity between ECM/PCM connector terminal A36 and body ground.

 

Is there continuity?


YES - Go to 35.


NO - Repair open in the wire between the ECM/PCM (A36) and DLC terminal No. 6.n


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

 

36.Check for continuity between ECM/PCM connector terminal A37 and body ground.

 

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.n


NO - Repair open in the wire between the ECM/PCM (A37) and DLC terminal No. 14.n

37.Try to start the engine.

Does the engine start and idle smoothly?


YES - Go to F-CAN circuit troubleshooting.n


NO - Go to 38.


38.Turn the ignition switch OFF.

39.Check the No. 2 IG MAIN (50 A) fuse in the under-hood fuse/relay box.

Is the fuse OK?


YES - Repair open in the wire between the No. 2 IG MAIN (50A) fuse and the ignition switch. If the wire is OK, go to 37.


NO - Repair short in the wire between the No. 2 IG MAIN (50 A) fuse and the under-hood fuse/relay box. Also replace the No. 2 IG MAIN (50 A) fuse.n

40.Inspect the No. 19 FI MAIN (15 A) fuse in the under-hood fuse/relay box.

Is the fuse OK?


YES - Go to 47.


NO - Go to 41.


41.Remove the blown No. 19 FI MAIN (15 A) fuse from the under-hood fuse/relay box.

42.Remove PGM-FI main relay 1 (C) (A) from the under-hood fuse/relay box.

 

43.Check for continuity between body ground and PGM-FI main relay 1 (C) 4P connector terminals No. 1 and No. 3 individually.

 

Is there continuity?


YES - Replace the under-hood fuse/relay box. Also replace the No. 19 FI MAIN (15 A) fuse.n


NO - Go to 44.

44.Disconnect each of the components or connectors below, one at a time, and check for continuity between PGM-FI main relay 1 (C) 4P connector terminal No. 2 and body ground.

  • PGM-FI main relay 2 (FUEL PUMP)
  • ECM/PCM connector A (44P)
  • Each injector 2P connector
  • Camshaft position (CMP) sensor B 3P connector
  • Crankshaft position (CKP) sensor 3P connector
  • Ignition coil relay
  • Electronic throttle control system (ETCS) control relay

 

Does continuity go away when one of the above components is disconnected?


YES - Replace the component that made the short to body ground go away when disconnected. If the item 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. 19 FI MAIN (15 A) fuse.n


NO - Go to 45.


45.Disconnect the all connectors from these components:

  • PGM-FI main relay 2 (FUEL PUMP)
  • ECM/PCM connector A (44P)
  • Injectors
  • Camshaft position (CMP) sensor B
  • Crankshaft position (CKP) sensor
  • Ignition coil relay
  • Electronic throttle control system (ETCS) control relay

46.Check for continuity between PGM-FI main relay 1 (C) 4P connector terminal No. 2 and body ground.

 

Is there continuity?


YES - Repair short in the wire between PGM-FI main relay 1 (C) and each item. Also replace the No. 19 FI MAIN (15 A) fuse.n


NO - Replace  PGM-FI main relay 1 (C). Also replace the No. 19 FI MAIN (15 A) fuse.n


47.Inspect the No. 2 FUEL PUMP (15 A) fuse in the under-dash fuse/relay box.

Is the fuse OK?


YES - Go to 60.


NO - Go to 48.


48.Remove the blown No. 2 FUEL PUMP (15 A) fuse in the under-dash fuse/relay box.

49.Jump the SCS line with the HDS.

50.Disconnect ECM/PCM connector C (44P).

51.Check for continuity between ECM/PCM connector terminal C36 and body ground.

 

Is there continuity?


YES - Go to 52.


NO - Replace the No. 2 FUEL PUMP (15 A) fuse, and 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.n


52.Remove PGM-FI main relay 2 (FUEL PUMP) (A) from the under-dash fuse/relay box.

 

53.Check for continuity between ECM/PCM connector terminal C36 and body ground.

 

Is there continuity?


YES - Repair short in the wire between the No. 2 FUEL PUMP (15 A) fuse and the ECM/PCM (C36), between the No. 2 FUEL PUMP (15 A) fuse and PGM-FI main relay 2 (FUEL PUMP), or between the No. 2 FUEL PUMP (15 A) fuse and the immobilizer control unit. Also replace the No. 2 FUEL PUMP (15 A) fuse.n


NO - Go to 54.


54.Remove the rear seat cushion.

55.Remove the rear floor upper cross-member, and the access panel from the floor.

56.Disconnect the fuel pump 4P connector.

57.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 (FUEL PUMP). Also replace the No. 2 FUEL PUMP (15 A) fuse.n


NO - Go to 58.


58.Reinstall PGM-FI main relay 2 (FUEL PUMP) (A).

 

59.Check for continuity between fuel pump 4P connector terminal No. 2 and body ground.

 

Is there continuity?


YES - Replace  PGM-FI main relay 2 (FUEL PUMP). Also replace the No. 2 FUEL PUMP (15 A) fuse.n


NO - Check the fuel pump, and replace it if necessary. Also replace the No. 2 FUEL PUMP (15 A) fuse.n


60.Jump the SCS line with the HDS.

61.Disconnect ECM/PCM connectors A (44P) and C (44P).

62.Turn the ignition switch ON (II).

63.Measure voltage between ECM/PCM connector terminal C36 and body ground.

 

Is there battery voltage?


YES - Go to 64.


NO - Repair open in the wire between the No. 2 FUEL PUMP (15 A) fuse and the ECM/PCM (C36).n


64.Measure voltage between ECM/PCM connector terminal A6 and body ground.

 

Is there battery voltage?


YES - Go to 69.


NO - Go to 65.


65.Turn the ignition switch OFF.

66.Remove PGM-FI main relay 1 (C) (A) from the under-hood fuse/relay box.

 

67.Measure voltage between PGM-FI main relay 1 (C) 4P connector terminal No. 3 and body ground.

 

Is there battery voltage?


YES - Go to 68.


NO - Replace the under-hood fuse/relay box.n

68.Check for continuity between PGM-FI main relay 1 (C) 4P connector terminal No. 4 and ECM/PCM connector terminal A6.

 

Is there continuity?


YES - Test PGM-FI main relay 1 (C). If the relay is OK, 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.n


NO - Repair open in the wire between the ECM/PCM (A6) and PGM-FI main relay 1 (C).n

69.Turn the ignition switch OFF.

70.Remove PGM-FI main relay 1 (C) (A) from the under-hood fuse/relay box.

 

71.Measure voltage between PGM-FI main relay 1 (C) 4P connector terminal No. 1 and body ground.

 

Is there battery voltage?


YES - Go to 72.


NO - Replace the under-hood fuse/relay box.n

72.Check for continuity between PGM-FI main relay 1 (C) 4P connector terminal No. 2 and ECM/PCM connector terminal A8.

 

Is there continuity?


YES - Go to 73.


NO - Repair open in the wire between the ECM/PCM (A8) and PGM-FI main relay 1 (C).n


73.Test PGM-FI main relay 1 (C).

Is PGM-FI main relay 1 (C) OK?


YES - Go to 74.


NO - Replace  PGM-FI main relay 1 (C).n

74.Disconnect ECM/PCM connector B (44P).

75.Check for continuity between body ground and ECM/PCM connector terminals B1, B36, C2, C40 and C44 individually.

 

Is there continuity?


YES - Go to 76.


NO - Repair open in the wire between the ECM/PCM (B1, B36, C2, C40, C44) and G101.n

76.Check for continuity between ECM/PCM connector terminal C13 and body ground.

 

Is there continuity?


YES - Go to 77.


NO - Go to 78.


77.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 - Replace the part that caused an open when it was disconnected.n


NO - Repair short in the wire between the ECM/PCM (C13) and the MAP sensor or the output shaft (countershaft) speed sensor.n

78.Check for continuity between ECM/PCM connector terminal B18 and body ground.

 

Is there continuity?


YES - Go to 79.


NO - Go to 80.


79.Continue to check for continuity between ECM/PCM connector terminal B18 and body ground, while disconnecting these parts, one at a time:

  • EGR valve 6P connector
  • Input shaft (mainshaft) speed sensor 3P connector

Does continuity go away when one of the above components is disconnected?


YES - Replace the part that caused an open when it was disconnected.n


NO - Repair short in the wire between the ECM/PCM (B18) and the EGR valve or the input shaft (mainshaft) speed sensor.n

80.Check for continuity between ECM/PCM connector terminal C12 and body ground.

 

Is there continuity?


YES - Go to 81.


NO - Go to 82.


81.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.n


NO - Replace the throttle body.n

82.Check for continuity between ECM/PCM connector terminal A25 and body ground.

 

Is there continuity?


YES - Go to 83.


NO - Go to 84.


83.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 A.n


NO - Replace the accelerator pedal module.n

84.Check for continuity between ECM/PCM connector terminal A24 and body ground.

 

Is there continuity?


YES - Go to 85.


NO - Go to 86.


85.Continue to check for continuity between ECM/PCM connector terminal A24 and body ground, while disconnecting the APP sensor 6P connector.

Is there continuity?


YES - Repair short in the wire between the ECM/PCM (A24) and APP sensor B.n


NO - Replace the accelerator pedal module.n

86.Check for continuity between ECM/PCM connector terminal A19 and body ground.

 

Is there continuity?


YES - Go to 87.


NO - 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.n


87.Continue to check for continuity between ECM/PCM connector terminal A19 and body ground, while disconnecting the A/C pressure sensor 3P connector.

Is there continuity?


YES - Repair short in the wire between the ECM/PCM (A19) and the A/C pressure sensor.n


NO - Replace the A/C pressure sensor.n