F-CAN Circuit Troubleshooting
F-CAN Circuit TroubleshootingNOTE: Information marked with an asterisk (*) applies to the CAN L line.
1. Turn the ignition switch OFF.
2. Jump the SCS line with the HDS.
3. Disconnect PCM connector A (44P), then disconnect the HDS.
4. Measure resistance between PCM connector terminals A36 and A37.
Is there about 99 - 121 ohms (95 - 116 ohms (with TPMS))?
YES - Go to step 33.
NO - Go to step 5.
5. Disconnect the gauge control module (tach) 36P connector.
6. Disconnect the ABS modulator-control unit 25P connector.
7. Disconnect SRS unit connector A (28P).
8. With TPMS: Disconnect TPMS control unit 20P connector.
9. Check for continuity between PCM connector terminals A36 and A37.
Is there continuity?
YES - Repair short in the wires between PCM connector terminals A36 and A37 *.
NO - Go to step 10.
10. Connect PCM connector terminal A36 to body ground with a jumper wire.
11. Check for continuity between gauge control module (tach) 36P connector terminal No. 1 and body ground.
Is there continuity?
YES - Go to step 12.
NO - Repair open in the wire between the PCM (A36) and the gauge control module (tach).
12. Check for continuity between ABS modulator-control unit 25P connector terminal No. 1 and body ground.
Is there continuity?
YES - Go to step 13.
NO - Repair open in the wire between the PCM (A36) and the ABS modulator-control unit.
13. Check for continuity between SRS unit connector A (28P) terminal No. 11 and body ground.
Is there continuity?
YES -
- With TPMS: Go to step 14.
- Without TPMS: Go to step 15.
NO - Repair open in the wire between the PCM (A36) and the SRS unit.
14. Check for continuity between TPMS control unit 20P connector terminal No. 2 and body ground.
Is there continuity?
YES - Go to step 15.
NO - Repair open in the wire between the PCM (A36) and the TPMS control unit.
15. Remove the jumper wire from PCM connector A (44P).
16. Connect 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 - Go to step 18.
NO - Repair open in the wire between the PCM (A37) and the gauge control module (tach).
18. Check for continuity between ABS modulator-control unit 25P connector terminal No. 17 and body ground.
Is there continuity?
YES - Go to step 19.
NO - Repair open in the wire between the PCM (A37) and the ABS modulator-control unit.
19. Check for continuity between SRS unit connector A (28P) terminal No. 12 and body ground.
Is there continuity?
YES -
- With TPMS: Go to step 20.
- Without TPMS: Go to step 21.
NO - Repair open in the wire between the PCM (A37) and the SRS unit.
20. Check for continuity between TPMS control unit 20P connector terminal No. 11 and body ground.
Is there continuity?
YES - Go to step 21.
NO - Repair open in the wire between the PCM (A37) and the TPMS control unit.
21. Remove the jumper wire from PCM connector A (44P).
22. Reconnect the gauge control module (tach) 36P connector.
23. Measure resistance between PCM connector terminals A36 and A37.
Is there about 108-132 ohms?
YES- Go to step24.
NO - Substitute a known-good gauge control module (tach), If the HDS identifies the vehicle, replace the original gauge control module (tach),
24. Disconnect the gauge control module (tach) 36P connector.
25. Reconnect the ABS modulator-control unit 25P connector.
26. Measure resistance between PCM connector terminals A36 and A37.
Is there about 2.34-2.86 kohms?
YES - Go to step 27.
NO - Substitute a known-good ABS modulator-control unit, If the HDS identifies the vehicle, replace the original ABS modulator-control unit,
27. Disconnect the ABS modulator-control unit 25P connector.
28. Reconnect SRS unit connector A (28P).
29. Measure resistance between PCM connector terminals A36 and A37.
Is there about 2.34-2.86 kohms?
YES - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM,
NO -
- With TPMS: Go to step 30.
- Without TPMS: Substitute a known-good SRS unit, If the HDS identifies the vehicle, replace the original SRS unit,
30. Disconnect SRS unit connector A (28P).
31. Reconnect the TPMS control unit 20P connector.
32. Measure resistance between PCM connector terminals A36 and A37.
Is there about 2.34-2.86 kohms?
YES - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM,
NO - Substitute a known-good TPMS control unit, If the HDS identifies the vehicle, replace the original TPMS control unit,
33. Disconnect the gauge control module (tach) 36P connector,
34. Disconnect the ABS modulator-control unit 25P connector,
35. Disconnect SRS unit connector A (28P),
36. With TPMS: Disconnect the TPMS control unit 20P connector.
37. Check for continuity between PCM connector terminal A36 and body ground.
Is there continuity?
YES - Repair short in the wire between PCM connector terminal A36 and the gauge control module (tach), the ABS modulator-control unit, the SRS unit, the TPMS control unit (with TPMS), or the DLC.
NO - Go to step 38.
38. Check for continuity between PCM connector terminal A37 and body ground.
Is there continuity?
YES - Repair short in the wire between PCM connector terminal A37 and the gauge control module (tach), the ABS modulator-control unit, the SRS unit, the TPMS control unit (with TPMS), or the DLC.
NO - Go to step 39.
39. Reconnect all connectors.
40. Connect the HDS to the DLC.
41. Disconnect the gauge control module (tach) 36P connector.
42. Turn the ignition switch ON (II), and read the HDS. Does the HDS identify the vehicle?
YES - Replace the gauge control module (tach),
NO - Go to step 43.
43. Turn the ignition switch OFF.
44. Reconnect the gauge control module (tach) 36P connector.
45. Disconnect the ABS modulator-control unit 25P connector.
46. 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 47.
47. Turn the ignition switch OFF.
48. Reconnect the ABS modulator-control unit 25P connector.
49. Disconnect SRS unit connector A (28P).
50. Turn the ignition switch ON (II), and read the HDS. Does the HDS identify the vehicle?
YES - Replace the SRS unit,
NO -
- With TPMS: Go to step 51.
- Without TPMS: Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM,
51. Turn the ignition switch OFF.
52. Reconnect SRS unit connector A (28P).
53. Disconnect the TPMS control unit 20P connector.
54. 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 PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM,