B2188

DTC Troubleshooting: B2188

DTC B2188: Communication Line (UART Line) Circuit Open

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A. Troubleshooting - B-CAN System Diagnosis Test Mode A

1. Clear the DTCs with the HDS.

2. Turn the ignition switch to LOCK (0) and then back to ON (II).

3. Open and close the each window by operating the front passenger's, left rear, and right rear power window switches.

4. Check for DTCs with the HDS.

Is DTC B2188 indicated, and does the any window fail to open or close?
YES - Go to step 5.

NO - Intermittent failure, the UART line is OK at this time.


5. Turn the ignition switch to LOCK (0).

6. Disconnect these connectors:
- Driver's MPCS unit connector A (40P)

- Power window master switch 6P connector

- Front passenger's MPCS unit connector A (28P)

- Left rear power window switch 14P connector

- Right rear power window switch 14P connector

7. Check for continuity between driver's MPCS unit connector A (40P) terminal No. 8 and front passenger's MPCS unit connector A (28P) terminal No. 4.

Is there continuity?
YES - Go to step 8.

NO - Repair an open in the wire, or replace the faulty passenger's under-dash fuse/relay box.






8. Check for continuity between driver's MPCS unit connector A (40P) terminal No. 8 and right rear power window switch 14P connector terminal No. 2.

Is there continuity?
YES - Go to step 9.

NO - Repair an open in the wire, or replace the faulty passenger's under-dash fuse/relay box.






9. Check for continuity between driver's MPCS unit connector A (40P) terminal No. 8 and left rear power window switch 14P connector terminal No. 2.

Is there continuity?
YES - Go to step 10.

NO - Repair an open in the wire.






10. Check for continuity between driver's MPCS unit connector A (40P) terminal No. 8 and power window master switch 6P connector terminal No. 6.

Is there continuity?
YES - Go to step 11.

NO - Repair an open in the wire.






11. Substitute a known-good power window master switch, and do the power window control unit learning procedure. Testing and Inspection

12. Connect these connectors:
- Driver's MPCS unit connector A (40P)

- Front passenger's MPCS unit connector A (28P)

- Left rear power window switch 14P connector

- Right rear power window switch 14P connector

13. Turn the ignition switch to ON (II).

14. Clear the DTCs with the HDS.

15. Open and close the each window by operating the power window master switch.

16. Check for DTCs with the HDS.

Is DTC B2188 indicated?
YES - Go to step 17.

NO - The original power window master switch is faulty; replace it.


17. Turn the ignition switch to LOCK (0).

18. Substitute a known-good front passenger's MPCS unit.

19. Turn the ignition switch to ON (II).

20. Clear the DTCs with the HDS.

21. Open and close the front passenger's power window by operating the front passenger's power window switch.

22. Check for DTCs with the HDS.

Is DTC B2188 indicated?
YES - Go to step 23.

NO - The original front passenger's MPCS unit is faulty; replace it.


23. Turn the ignition switch to LOCK (0).

24. Substitute a known-good left rear power window switch.

25. Turn the ignition switch to ON (II).

26. Clear the DTCs with the HDS.

27. Open and close the left rear power window by operating the left rear power window switch.

28. Check for DTCs with the HDS.

Is DTC B2188 indicated?
YES - Go to step 29.

NO - The original left rear power window switch is faulty; replace it.


29. Turn the ignition switch to LOCK (0).

30. Substitute a known-good right rear power window switch.

31. Turn the ignition switch to ON (II).

32. Clear the DTCs with the HDS.

33. Open and close the right rear power window by operating the right rear power window switch.

34. Check for DTCs with the HDS.

Is DTC B2188 indicated?
YES - Replace the driver's MPCS unit.

NO - The original right rear power window power switch is faulty; replace it.