F-CAN Circuit Troubleshooting
F-CAN Circuit TroubleshootingNOTE: Information marked with an asterisk (*) applies to the CANL Line.
1. Turn the ignition switch OFF.
2. Jump the SCS line with the HDS.
3. Disconnect ECM connector A (44P), then disconnect the HDS.
4. Measure resistance between ECM connector terminals A36 and A37.
Is there about 95-116 ohms (with ABS), 91-111 ohms, (with VSA system), or 88-107 ohms (with VSA system and TPMS)?
YES - Go to step 49.
NO - Go to step 5.
5. Disconnect the gauge control module (tach)36P connector.
6. Disconnect the ABS modulator-control unit 25P connector (or the VSA modulator-control unit 37P connector and the yaw rate/lateral acceleration sensor 4P connector).
7. Disconnect the SRS unit 28P connector.
8. Disconnect EPS control unit connector D (28P).
9. With TPMS: Disconnect the TMPS control unit 20P connector.
10. Check for continuity between ECM connector terminals A36 and A37.
Is there continuity?
YES - Repair short in the wires between ECM connector terminals A36 and A37.
NO - Go to step 11.
11. Connect ECM 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 ABS: Go to step 13.
- With VSA system: Go to step 14.
NO - Repair open in the wire between the ECM (A36) and the gauge control module (tach).
13. Check for continuity between ABS modulator-control unit 25P connector terminal No. 1 and body ground.
Is there continuity?
YES - Go to step 16.
NO - Repair open in the wire between the ECM (A36) and the ABS modulator-control unit.
14. Check for continuity between VSA modulator-control unit 37P connector terminal No. 15 and body ground.
Is there continuity?
YES - Go to step 15.
NO - Repair open in the wire between the ECM (A36) and the VSA modulator-control unit.
15. Check for continuity between yaw rate-lateral acceleration sensor 5P connector terminal No. 3 and body ground.
Is there continuity?
YES - Go to step 16.
NO - Repair open in the wire between the ECM (A36) and the yaw rate-lateral acceleration sensor.
16. Check for continuity between SRS unit connector A (28P) terminal No. 11 and body ground.
Is there continuity?
YES - Go to step 17.
NO - Repair open in the wire between the ECM (A36) and the SRS unit.
17. Check for continuity between EPS control unit connector D (28P) terminal No. 1 and body ground.
Is there continuity?
YES
- With TPMS: Go to step 18.
- Without TPMS: Go to step 19.
NO - Repair open in the wire between the ECM (A36) and the EPS control unit.
18. Check for continuity between TPMS control unit 20P connector terminal No. 2 and body ground.
Is there continuity?
YES - Go to step 19.
NO - Repair open in the wire between the ECM (A36) and the TPMS control unit.
19. Remove the jumper wire from ECM connector A (44P).
20. Connect ECM connector terminal A37 to body ground with a jumper wire.
21. Check for continuity between gauge control module (tach) 36P connector terminal No. 19 and body ground.
Is there continuity?
YES
- With ABS: Go to step 22.
- With VSA system: Go to step 23.
NO - Repair open in the wire between the ECM (A37) and the gauge control module (tach).
22. Check for continuity between ABS modulator-control unit 25P connector terminal No. 17 and body ground.
Is there continuity?
YES - Go to step 25.
NO - Repair open in the wire between the ECM (A37) and the ABS modulator-control unit.
23. Check for continuity between VSA modulator-control unit 37P connector terminal No. 1 and body ground.
Is there continuity?
YES - Go to step 24.
NO - Repair open in the wire between the ECM (A37) and the VSA modulator-control unit.
24. Check for continuity between yaw rate-lateral acceleration sensor 5P connector terminal No. 4 and body ground.
Is there continuity?
YES - Go to step 25.
NO - Repair open in the wire between the ECM (A37) and the yaw rate-lateral acceleration sensor.
25. Check for continuity between SRS unit connector A (28P) terminal No. 12 and body ground.
Is there continuity?
YES - Go to step 26.
NO - Repair open in the wire between the ECM (A37) and the SRS unit.
26. Check for continuity between EPS control unit connector D (28P) terminal No. 15 and body ground.
Is there continuity?
YES -
- With TPMS: Go to step 27.
- Without TPMS: Go to step 28.
NO - Repair open in the wire between the ECM (A37) and the EPS control unit.
27. Check for continuity between TPMS control unit 20P connector terminal No. 11 and body ground.
Is there continuity?
YES - Go to step 28.
NO - Repair open in the wire between the ECM (A37) and the TPMS control unit.
28. Remove the jumper wire from ECM connector A (44P).
29. Reconnect the gauge control module (tach) 36P connector.
30. Measure resistance between ECM connector terminals A36 and A37.
Is there about 108-132 ohms?
YES
- With ABS: Go to step 31.
- With VSA system: Go to step 34.
NO - Substitute a known-good gauge control module (tach). If the HDS identifies the vehicle, replace the original gauge control module (tach).
31. Disconnect the gauge control module (tach) 36P connector.
32. Reconnect the ABS modulator-control unit25P connector.
33. Measure resistance between ECM connector terminals A36 and A37.
Is there about 2.34-2.86 kohms?
YES - Go to step 40.
NO - Substitute a known-good ABS modulator-control unit. If the HDS identifies the vehicle, replace the original ABS modulator-control unit.
34. Disconnect the gauge control module (tach) 36P connector.
35. Reconnect the VSA modulator-control unit 37P connector.
36. Measure resistance between ECM connector terminals A36 and A37.
Is there about 2.34-2.86 kohms?
YES - Go to step 37.
NO - Substitute a known-good VSA modulator-control unit. If the HDS identifies the vehicle, replace the original VSA modulator-control unit.
37. Disconnect the VSA modulator-control unit 37P connector.
38. Reconnect the yaw rate/lateral acceleration sensor 5P connector.
39. Measure resistance between ECM connector terminals A36 and A37.
Is there about 2.34-2.86 kohms?
YES - Go to step 40.
NO - Substitute a known-good yaw rate/lateral acceleration sensor. If the HDS identifies the vehicle, replace the original yaw rate/lateral acceleration sensor.
40. Disconnect the ABS modulator-control unit 25P connector (or the yaw rate/lateral acceleration sensor 5P connector).
41. Reconnect SRS unit connector A (28P).
42. Measure resistance between ECM connector terminals A36 and A37.
Is there about 2.34-2.86 kohms?
YES - Go to step 43.
NO - Substitute a known-good SRS unit. If the HDS identifies the vehicle, replace the original SRS unit.
43. Disconnect SRS unit connector A (28P).
44. Reconnect EPS control unit connector D (28P).
45. Measure resistance between ECM connector terminals A36 and A37.
Is there about 2.34-2.86 kohms?
YES -
- With TPMS: Go to step 46.
- Without TPMS: Update the ECM if it does hot have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
NO - Substitute a known-good EPS control unit. If the HDS identifies the vehicle, replace the original EPS control unit.
46. Disconnect EPS control unit connector D (28P).
47. Reconnect the TPMS control unit 20P connector.
48. Measure resistance between ECM connector terminals A36 and A37.
Is there about 2.34-2.86 kohms?
YES - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
NO - Substitute a known-good TPMS control unit. If the HDS identifies the vehicle, replace the original TPMS control unit.
49. Disconnect the gauge control module (tach) 36P connector.
50. Disconnect the ABS modulator-control unit 25P connector (or the VSA modulator-control unit 37P connector and the yaw rate/lateral acceleration sensor 5P connector).
51. Disconnect SRS unit connector A (28P).
52. Disconnect EPS control unit connector D (28P).
53. With TPMS: Disconnect the TPMS control unit 20P connector.
54. Check for continuity between ECM connector terminal A36 and body ground.
Is there continuity?
YES - Repair short in the wire between ECM connector terminal A36 and the gauge control module, the ABS modulator-control unit, the VSA modulator-control unit, the yaw rate/lateral acceleration sensor, the SRS unit, the EPS control unit, TPMS control unit (with TPMS), or the DLC.
NO - Go to step 55.
55. Check for continuity between ECM connector terminal A37 and body ground.
Is there continuity?
YES - Repair short in the wire between ECM connector terminal A37 and the gauge control module, 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 (with TPMS), or the DLC.
NO - Go to step 56.
56. Reconnect all connectors.
57. Connect the HDS to the DLC.
58. Disconnect the gauge control module (tach) 36P connector.
59. Turn the ignition switch ON (II), and read the HDS.
Does the HDS identify the vehicle?
YES - Replace the gauge control module (tach).
NO -
- With ABS: Go to step 60.
- With VSA system: Go to step 64.
60. Turn the ignition switch OFF.
61. Reconnect the gauge control module (tach) 36P connector.
62. Disconnect the ABS modulator-control unit 25P connector.
63. Turn the ignition switch ON (II), and read the HDS.
Does the HDS identify the vehicle?
YES - Replace the ABS modulator-control unit.
NO - Go to step 72.
64. Turn the ignition switch OFF.
65. Reconnect the gauge control module (tach) 36P connector.
66. Disconnect the VSA modulator-control unit 37P connector.
67. Turn the ignition switch ON (II), and read the HDS.
Does the HDS identify the vehicle?
YES - Replace the VSA modulator-control unit.
NO - Go to step 68.
68. Turn the ignition switch OFF.
69. Reconnect the VSA modulator-control unit 37P connector.
70. Disconnect the yaw rate/lateral acceleration sensor 5P connector.
71. Turn the ignition switch ON (II), and read the HDS.
Does the HDS identify the vehicle?
YES - Replace the yaw rate/lateral acceleration sensor.
NO - Go to step 72.
72. Turn the ignition switch OFF.
73. Reconnect the ABS modulator-control unit 25P connector (or yaw rate/lateral acceleration sensor 5P connector).
74. Disconnect SRS unit connector A (28P).
75. Turn the ignition switch ON (II), and read the HDS.
Does the HDS identify the vehicle?
YES - Replace the SRS unit.
NO - Go to step 76.
76. Turn the ignition switch OFF.
77. Reconnect SRS unit connector A (28P).
78. Disconnect EPS control unit connector D (28P).
79. Turn the ignition switch ON (II), and read the HDS.
Does the HDS identify the vehicle?
YES - Replace the EPS control unit.
NO
- With TPMS: Go to step 80.
- Without TPMS: Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
80. Turn the ignition switch OFF.
81. Reconnect EPS control unit connector D (28P).
82. Disconnect the TPMS control unit 20P connector.
83. Turn the ignition switch ON (II), and read the HDS.
Does the HDS identify the vehicle?
YES - Replace the TPMS control unit.
NO - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.