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 PCM connector A (44P), then disconnect the HDS.
4. Measure the 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. Gauge Control Module Replacement
6. Disconnect the ABS modulator-control unit 25P connector. Service and Repair
7. Disconnect SRS unit connector A (28P). SRS Unit Replacement
8. With TPMS: Disconnect TPMS control unit 20P connector. Service and Repair
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 the resistance between PCM connector terminals A36 and A37.
Is there about 108-132 Ohms?
YES - Go to step 24.
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
24. Disconnect the gauge control module (tach) 36P connector.
25. Reconnect the ABS modulator-control unit 25P connector.
26. Measure the 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. Service and Repair If the HDS identifies the vehicle, replace the original ABS modulator-control unit. Service and Repair
27. Disconnect the ABS modulator-control unit 25P connector.
28. Reconnect SRS unit connector A (28P).
29. Measure the 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, PCM Update or substitute a known-good PCM, Initial Inspection and Diagnostic Overview then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM. Service and Repair
NO -
- With TPMS: Go to step 30.
- Without TPMS: Substitute a known-good SRS unit. SRS Unit Replacement If the HDS identifies the vehicle, replace the original SRS unit. SRS Unit Replacement
30. Disconnect SRS unit connector A (28P).
31. Reconnect the TPMS control unit 20P connector.
32. Measure the 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, PCM Update or substitute a known-good PCM, Initial Inspection and Diagnostic Overview then recheck. If the symptom/indication goes away with a known-good PCM, replace the original 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
33. Disconnect the gauge control module (tach) 36P connector. Gauge Control Module Replacement
34. Disconnect the ABS modulator-control unit 25P connector. Service and Repair
35. Disconnect SRS unit connector A (28P). SRS Unit Replacement
36. With TPMS: Disconnect the TPMS control unit 20P connector. Service and Repair
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. Initial Inspection and Diagnostic Overview
41. Disconnect the gauge control module (tach) 36P connector.
42. 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 - Go to step 43.
43. Turn the ignition switch to LOCK (0).
44. Reconnect the gauge control module (tach) 36P connector.
45. Disconnect the ABS modulator-control unit 25P connector.
46. 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 - Go to step 47.
47. Turn the ignition switch to LOCK (0).
48. Reconnect the ABS modulator-control unit 25P connector.
49. Disconnect SRS unit connector A (28P).
50. 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 TPMS: Go to step 51.
- Without TPMS: Update the PCM if it does not have the latest software, PCM Update or substitute a known-good PCM, Initial Inspection and Diagnostic Overview then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM. Service and Repair
51. Turn the ignition switch to LOCK (0).
52. Reconnect SRS unit connector A (28P).
53. Disconnect the TPMS control unit 20P connector.
54. 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 PCM if it does not have the latest software, PCM Update or substitute a known-good PCM, Initial Inspection and Diagnostic Overview then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM. Service and Repair