PGM-FI System

DTC Troubleshooting: U0104

DTC U0104:

F-CAN A Malfunction (PCM-Adaptive Cruise Control (ACC) Unit)

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information Initial Inspection and Diagnostic Overview.

1. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

2. Check for Pending or Confirmed DTCs with the HDS.

Are DTC U0029 and U0104 indicated at the same time?

YES -

Go to the troubleshooting for DTC U0029 PGM-FI System.

NO -

Go to step 3.

3. Clear the DTC with the HDS.

4. Check for Pending or Confirmed DTCs with the HDS.

Is DTC U0104 indicated?

YES -

Go to step 5.

NO -

Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the ACC unit and the PCM.

5. Check for communication to the DRIVING SUPPORT system with the HDS.

Does the HDS communicate with the ACC unit?

YES -

Go to step 6.

NO -

Go to the symptom troubleshooting for ACC indicator does not go off ACC Indicator Does Not Go Off.

6. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

7. Jump the SCS line with the HDS.

8. Disconnect the ACC unit 20P connector.

9. Disconnect PCM connector A (49P).

10. Check for continuity between PCM connector terminal A48 and ACC unit 20P connector terminal No. 10.





Is there continuity?

YES -

Go to step 11.

NO -

Repair an open in the wire between the PCM (A48) and the ACC unit, then go to step 12.

11. Check for continuity between PCM connector terminal A49 and ACC unit 20P connector terminal No. 20.





Is there continuity?

YES -

Update the ACC unit if it does not have the latest software Testing and Inspection, or substitute a known-good ACC unit Service and Repair, then go to step 12 and recheck. If DTC U0104 is not indicated after substitution, replace the original ACC unit Service and Repair, then go to step 12.

NO -

Repair an open in the wire between the PCM (A49) and the ACC unit, then go to step 12.

12. Reconnect all connectors.

13. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

14. Reset the PCM with the HDS.

15. Do the PCM idle learn procedure PCM Idle Learn Procedure.

16. Check for Pending or Confirmed DTCs with the HDS.

Is DTC U0122 indicated?

YES -

Check for poor connections or loose terminals at the ACC unit and the PCM, then go to step 1.

NO -

Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.