F-CAN Circuit Troubleshooting

F-CAN Circuit Troubleshooting

1. Turn the ignition switch to LOCK (0).

2. Jump the SCS line with the HDS.

3. Disconnect ECM/PCM connector A (44P), then disconnect the HDS.

4. Measure the resistance between ECM/PCM connector terminals A36 and A37 using the appropriate reading from the table below.





Is the resistance OK?
YES - Go to step 42.

NO - Go to step 5.






5. Disconnect the gauge control module (tach) 36P connector. Gauge Control Module Replacement

6. Disconnect the ABS modulator-control unit 25P connector Service and Repair or the VSA modulator-control unit 37P connector Service and Repair and the yaw rate/lateral acceleration sensor 4P connector. Service and Repair

7. Disconnect SRS unit connector A (28P). SRS Unit Replacement

8. With EPS: Disconnect EPS control unit connector D (28P). Service and Repair

9. With TPMS: Disconnect the TPMS control unit 20P connector. Service and Repair

10. Check for continuity between ECM/PCM connector terminals A36 and A37.

Is there continuity?
YES - Repair short in the wires between ECM/PCM connector terminals A36 and A37.

NO - Go to step 11.






11. Connect ECM/PCM connector terminal A36 to body ground with a jumper wire.






12. Check for continuity between gauge control module (tach) 36P connector terminal No. 1 and body ground.

Is there continuity?
YES -
- With VSA: Go to step 13.

- Without VSA: Go to step 14.


NO - Repair open in the wire between the ECM/PCM (A3) and the gauge control module (tach).






13. Check for continuity between VSA modulator-control unit 37P connector terminal No. 15 and body ground.

Is there continuity?
YES - Go to step 14.

NO - Repair open in the wire between the ECM/PCM (A36) and the VSA modulator-control unit.






14. Check for continuity between EPS control unit connector D (28P) terminal No. 1 and body ground.

Is there continuity?
YES - Go to step 15.

NO - Repair open in the wire between the ECM/PCM (A36) and the EPS control unit.






15. Remove the jumper wire from ECM/PCM connector A (44P).

16. Connect ECM/PCM connector terminal A37 to body ground with a jumper wire.






17. Check for continuity between gauge control module (tach) 36P connector terminal No. 19 and body ground.

Is there continuity?
YES -
- With VSA: Go to step 18.

- Without VSA: Go to step 19.


NO - Repair open in the wire between the ECM/PCM (A37) and the gauge control module (tach).






18. Check for continuity between VSA modulator-control unit 37P connector terminal No. 1 and body ground.

Is there continuity?
YES - Go to step 19.

NO - Repair open in the wire between the ECM/PCM (A37) and the VSA modulator-control unit.






19. Check for continuity between EPS control unit connector D (28P) terminal No. 15 and body ground.

Is there continuity?
YES - Go to step 20.

NO - Repair open in the wire between the ECM/PCM (A37) and the EPS control unit.






20. Remove the jumper wire from ECM/PCM connector A (44P).

21. Reconnect the gauge control module (tach) 36P connector.

22. Measure the resistance between ECM/PCM connector terminals A36 and A37.

Is there about 108-132 Ohms?
YES -
- With ABS: Go to step 23.

- With VSA: Disconnect the gauge control module (tach) 36P connector, Gauge Control Module Replacement then go to step 27.


NO - Substitute a known-good gauge control module (tach). Gauge Control Module Replacement If the HDS identifies the vehicle, replace the original gauge control module (tach). Gauge Control Module Replacement






23. Disconnect the gauge control module (tach) 36P connector.

24. Reconnect the ABS modulator-control unit 25P connector.

25. Measure the resistance between ECM/PCM connector terminals A36 and A37.

Is there about 2.34-2.86 kOhms?
YES - Go to step 26.

NO - Substitute a known-good ABS modulator-control unit. Service and Repair If the HDS identifies the vehicle, replace the original ABS modulator-control unit. Service and Repair






26. Disconnect the ABS modulator-control unit 25P connector, then go to step 33.

27. Reconnect the VSA modulator-control unit 37P connector.

28. Measure the resistance between ECM/PCM connector terminals A36 and A37.

Is there about 2.34-2.86 kOhms?
YES - Go to step 29.

NO - Substitute a known-good VSA modulator-control unit. Service and Repair If the HDS identifies the vehicle, replace the original VSA modulator-control unit. Service and Repair






29. Disconnect the VSA modulator-control unit 37P connector.

30. Reconnect the yaw rate-lateral acceleration sensor 5P connector.

31. Measure the resistance between ECM/PCM connector terminals A36 and A37.

Is there about 2.34-2.86 kOhms?
YES - Go to step 32.

NO - Substitute a known-good yaw rate-lateral acceleration sensor. Service and Repair If the HDS identifies the vehicle, replace the original yaw rate-lateral acceleration sensor. Service and Repair






32. Disconnect the yaw rate-lateral acceleration sensor 5P connector.

33. Reconnect SRS unit connector A (28P).

34. Measure the resistance between ECM/PCM connector terminals A36 and A37.

Is there about 2.34-2.86 kOhms?
YES -
- With EPS: Go to step 35.

- Without EPS, but with TPMS: Disconnect SRS unit connector A (28P), then go to step 39.

- Without EPS and TPMS: Update the ECM/PCM if it does not have the latest software, ECM/PCM Update (A/T) or substitute a known-good ECM/PCM, Initial Inspection and Diagnostic Overview then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM. Service and Repair


NO - Substitute a known-good SRS unit. SRS Unit Replacement If the HDS identifies the vehicle, replace the original SRS unit. SRS Unit Replacement






35. Disconnect SRS unit connector A (28P).

36. Reconnect EPS control unit connector D (28P).

37. Measure the resistance between ECM/PCM connector terminals A36 and A37.

Is there about 2.34-2.86 kOhms?
YES -
- With TPMS: Go to step 38.

- Without TPMS: Update the ECM/PCM if it does not have the latest software, ECM/PCM Update (A/T) or substitute a known-good ECM/PCM, Initial Inspection and Diagnostic Overview then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM. Service and Repair


NO - Substitute a known-good EPS control unit. Service and Repair If the HDS identifies the vehicle, replace the original EPS control unit. Service and Repair






38. Disconnect EPS control unit connector D (28P).

39. Reconnect the TPMS control unit 20P connector.

40. Measure the resistance between ECM/PCM connector terminals A36 and A37.

Is there about 2.34-2.86 kOhms?
YES - Update the ECM/PCM if it does not have the latest software, ECM/PCM Update (A/T) or substitute a known-good ECM/PCM, Initial Inspection and Diagnostic Overview then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM. Service and Repair

NO - Substitute a known-good TPMS control unit. Service and Repair If the HDS identifies the vehicle, replace the original TPMS control unit. Service and Repair






41. Disconnect the gauge control module (tach) 36P connector. Gauge Control Module Replacement

42. Disconnect the ABS modulator-control unit 25P connector Service and Repair or the VSA modulator-control unit 37P connector Service and Repair and the yaw rate/lateral acceleration sensor 5P connector. Service and Repair

43. Disconnect SRS unit connector A (28P). SRS Unit Replacement

44. With EPS: Disconnect EPS control unit connector D (28P). Service and Repair

45. With TPMS: Disconnect the TPMS control unit 20P connector. Service and Repair

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

Is there continuity?
YES - Repair short in the wire between ECM/PCM connector terminal A36 and the gauge control module (tach), the ABS modulator-control unit, the VSA modulator-control unit, the yaw rate/lateral acceleration sensor, the SRS unit, the EPS control unit, the TPMS control unit, or the DLC.

NO - Go to step 47.






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

Is there continuity?
YES - Repair short in the wire between ECM/PCM connector terminal A37 and the gauge control module (tach), the ABS modulator-control unit, the VSA modulator-control unit, the yaw rate/lateral acceleration sensor, the SRS unit, the EPS control unit, the TPMS control unit, or the DLC.

NO - Go to step 48.






48. Reconnect all connectors.

49. Connect the HDS to the DLC. Initial Inspection and Diagnostic Overview

50. Disconnect the gauge control module (tach) 36P connector.

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

Does the HDS identify the vehicle?
YES - Replace the gauge control module (tach). Gauge Control Module Replacement

NO -
- With ABS: Go to step 52.

- With VSA: Turn the ignition switch to LOCK (0), then reconnect the gauge control module (tach) 36P connector, then go to step 58.



52. Turn the ignition switch to LOCK (0).

53. Reconnect the gauge control module (tach) 36P connector.

54. Disconnect the ABS modulator-control unit 25P connector.

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

Does the HDS identify the vehicle?
YES - Replace the ABS modulator-control unit. Service and Repair

NO - Turn the ignition switch to LOCK (0), and reconnect the ABS modulator-control unit 25P connector, then go to step 66.


56. Turn the ignition switch to LOCK (0).

57. Reconnect the ABS modulator-control unit 25P connector.

58. Disconnect the VSA modulator-control unit 37P connector.

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

Does the HDS identify the vehicle?
YES - Replace the VSA modulator-control unit. Service and Repair

NO - Go to step 60.


60. Turn the ignition switch to LOCK (0).

61. Reconnect the VSA modulator-control unit 37P connector.

62. Disconnect yaw rate-lateral acceleration sensor 5P connector.

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

Does the HDS identify the vehicle?
YES - Replace the yaw rate-lateral acceleration sensor. Service and Repair

NO - Go to step 64.


64. Turn the ignition switch to LOCK (0).

65. Reconnect the yaw rate-lateral acceleration sensor 5P connector.

66. Disconnect SRS unit connector A (28P).

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

Does the HDS identify the vehicle?
YES - Replace the SRS unit. SRS Unit Replacement

NO -
- With EPS: Go to step 68.

- Without EPS, but with TPMS: Reconnect SRS unit connector A (28P), then go to step 72.

- Without EPS and TPMS: Update the ECM/PCM if it does not have the latest software, ECM/PCM Update (A/T) or substitute a known-good ECM/PCM, Initial Inspection and Diagnostic Overview then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM. Service and Repair



68. Turn the ignition switch to LOCK (0).

69. Reconnect SRS unit connector A (28P).

70. Disconnect EPS control unit connector D (28P).

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

Does the HDS identify the vehicle?
YES - Replace the EPS control unit. Service and Repair

NO -
- With TPMS: Go to step 72.

- Without TPMS: Update the ECM/PCM if it does not have the latest software, ECM/PCM Update (A/T) or substitute a known-good ECM/PCM, Initial Inspection and Diagnostic Overview then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM. Service and Repair



72. Turn the ignition switch to LOCK (0).

73. Disconnect the TPMS control unit 20P connector.

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

Does the HDS identify the vehicle?
YES - Replace the TPMS control unit. Service and Repair

NO - Update the ECM/PCM if it does not have the latest software, ECM/PCM Update (A/T) or substitute a known-good ECM/PCM, Initial Inspection and Diagnostic Overview then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM. Service and Repair