Diesel Data: Automotive Repair

Information Bus: Testing and Inspection

F-CAN Circuit Troubleshooting

NOTE: 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 E (31P).
4. Disconnect HDS from the DLC.




5. Measure resistance between ECM connector terminals E11 and E24*.

Is there about 108-132 ohms ?

YES - Go to step 16.

NO - Go to step 6.

6. Disconnect the VSA modulator-control unit 47P connector.
7. Disconnect the steering angle sensor 5P connector.




8. Check for continuity between ECM connector terminal E11 and E24*.

Is there continuity?

YES - Repair short in the wires between the ECM connector terminals E11 and E24*.

NO - Go to step 9.




9. Connect ECM connector terminal E11 to body ground with a jumper wire.




10. Check for continuity between VSA modulator-control unit 47P connector terminal No. 11 and body ground.

Is there continuity?

YES - Go to step 11.

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




11. Check for continuity between steering angle sensor 5P connector terminal No. 4 and body ground.

Is there continuity?

YES - Go to step 12.

NO - Repair open in the wire between the ECM (El 1) and the steering angle sensor.

12. Remove the jumper wire from ECM connector E (31P).




13. Connect ECM connector terminal E24to body ground with a jumper wire.




14. Check for continuity between VSA modulator-control unit 47P connector terminal No. 15 and body ground.

Is there continuity?

YES - Go to step 15.

NO - Repair open in the wire between the ECM (E24) and the VSA modulator-control unit.




15. Check for continuity between steering angle sensor 5P connector terminal No. 2 and body ground.

Is there continuity?

YES - Replace the VSA modulator-control unit.

NO - Repair open in the wire between the ECM (E24) and the steering angle sensor.

16. Disconnect the VSA modulator-control unit 47P connector.
17. Disconnect the steering angle sensor 5P connector.




18. Check for continuity between ECM connector terminal E11 and body ground.

Is there continuity?

YES - Repair short in the wire between the ECM connector terminals E11 and the VSA modulator-control unit, the steering angle sensor, or the DLC.

NO - Go to step 19.




19. Check for continuity between ECM connector terminal E24 and body ground.

Is there continuity?

YES - Repair short in the wire between the ECM connector terminal E24 and the VSA modulator-control unit, the steering angle sensor, or the DLC.

NO - Go to step 20.




20. Check for continuity between VSA modulator-control unit 47P connector terminal No. 47 and body ground.

Is there continuity?

YES - Go to step 21.

NO - Repair open in the wire between the VSA modulator-control unit (No. 47) and body ground (G303).




21. Check for continuity between steering angle sensor 5P connector terminal No. 1 and body ground.

Is there continuity?

YES - Go to step 22.

NO - Repair open in the wire between the steering angle sensor (No. 1) and body ground (G401).

22. Reconnect the VSA modulator-control unit 47P connector.
23. Connect the HDS.
24. Turn the ignition switch ON (II), and read the HDS.

Does the HDS identify the vehicle?

YES - Replace the steering angle sensor.

NO - Go to step 25.

25. Substitute a known-good ECM.
26. Turn the ignition switch ON (II), and read the HDS.

Does the HDS identify the vehicle?

YES - System is OK at this time. Replace the original ECM.

NO - Replace the VSA modulator-control unit.