Information Bus: Testing and Inspection
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/PCM connector E (31P), then disconnect the HDS.
4. Measure resistance between ECM/PCM connector terminals E11 and E24.
Is there about 108 - 132 ohms?
YES - Go to step 20.
NO - Go to step 5.
5. Disconnect the gauge control module 40P connector.
6. Disconnect the ABS modulator-control unit25P connector.
7. Check for continuity between ECM/PCM connector terminals E11 and E24.
Is there continuity?
YES - Repair short in the wires between ECM/PCM connector terminals E11 and E24*.
NO - Go to step 8.
8. Connect ECM/PCM connector terminal E11 to body ground with a jumper wire.
9. Check for continuity between gauge control module 40P connector terminal No. 13 and body ground.
Is there continuity?
YES - Go to step 10.
NO - Repair open in the wire between the ECM/PCM (E11 land the gauge control module.
10. Check for continuity between ABS modulator-control unit 25P connector terminal No, 1 and body ground.
Is there continuity?
YES - Go to step 11.
NO - Repair open in the wire between the ECM/PCM (E11) and the ABS modulator-control unit.
11. Remove the jumper wire from ECM/PCM connector E(31P).
12. Connect ECM/PCM connector terminal E24 to body ground with a jumper wire.
13. Check for continuity between gauge control module 40P connector terminal No. 12 and body ground.
Is there continuity?
YES - Go to step 14.
NO - Repair open in the wire between the ECM/PCM (E24) and the gauge control module.
14. Check for continuity between ABS modulator-control unit 25P connector terminal No. 17 and body ground.
Is there continuity?
YES - Go to step 15.
NO - Repair open in the wire between the ECM/PCM (E24) and the ABS modulator- control unit.
15. Reconnect the gauge control module 40P connector.
16. Measure resistance between ECM/PCM connector terminals E11 and E24.
Is there about 112 - 136 ohms?
YES - Go to step 17.
NO - Substitute a known-good gauge control module. If the HDS identifies the vehicle, replace the original gauge control module.
17. Disconnect the gauge control module 40P connector.
18. Reconnect the ABS modulator-control unit25P connector.
19. Measure resistance between ECM/PCM connector terminals E11 and E24.
Is there about 2.34 - 2.86 Kohms?
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.
NO - Substitute a known-good ABS modulator-control unit. If the HDS identifies the vehicle, replace the original ABS modulator-control unit.
20. Disconnect the gauge control module 40P connector.
21. Disconnect the ABS modulator- control unit 25P connector.
22. Check for continuity between ECM/PCM connector terminal E11 and body ground.
Is there continuity?
YES - Repair short in the wire between ECM/PCM connector terminal E11 and the gauge control module, the ABS modulator-control unit, or the DLC.
NO - Go to step 23.
23. Check for continuity between ECM/PCM connector terminal E24 and body ground.
Is there continuity?
YES - Repair short in the wire between ECM/PCM connector terminal E24 and the gauge control module, the ABS modulator-control unit, or the DLC.
NO - Go to step 24.
24. Reconnect all connectors.
25. Connect the HDS to the DLC.
26. Disconnect the gauge control module 40P connector.
27. Turn the ignition switch ON (II), and read the HDS.
Does the HDS identify the vehicle?
YES - Replace the gauge control module.
NO - Go to step 28.
28. Turn the ignition switch OFF.
29. Reconnect the gauge control module 40P connector.
30. Disconnect the ABS modulator-control unit 25P connector.
31. Turn the ignition switch ON (II), and read the HDS.
Does the HDS identify the vehicle?
YES - Replace the ABS modulator-control unit.
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.