B2187

DTC Troubleshooting: B2187

DTC B2187:

UART Communication Error1 (Driver's MPCS Unit From DR Door ECU)

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. Operate the front passenger's, left rear and right rear power window switches.

4. Check for DTCs with the HDS.

Is DTC B2187 indicated?

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
- Moonroof motor/control unit 8P connector

7. Check for continuity between driver's MPCS unit connector A (40P) terminal No. 8 and body ground.





Is there continuity?

YES -

Repair a short to ground in the wire.

NO -

Go to step 8.

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

9. Measure the voltage between driver's MPCS unit connector A (40P) terminal No. 8 and body ground.





Is there voltage?

YES -

Repair a short to power in the wire.

NO -

Go to step 10.

10. Clear the DTCs with the HDS.

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

12. Wait for at least 6 seconds.

13. Check for DTCs with the HDS.

Is DTC B2187 indicated?

YES -

Replace the driver's MPCS unit Power Windows (Drivers MPCS Unit) Input Test/Replacement.

NO -

Go to step 14.

14. Reconnect the power window master switch 6P connector.

15. Clear the DTCs with the HDS.

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

17. Operate each switch of the power window master switch.

18. Check for DTCs with the HDS.

Is DTC B2187 indicated?

YES -

Replace the power window master switch Power Window Master Switch Replacement.

NO -

Go to step 19.

19. Reconnect front passenger's MPCS unit connector A (28P).

20. Clear the DTCs with the HDS.

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

22. Operate the front passenger's power window switch in each direction.

23. Check for DTCs with the HDS.

Is DTC B2187 indicated?

YES -

Replace the front passenger's MPCS unit Power Windows (Front Passengers MPCS Unit) Input Test/Replacement.

NO -

Go to step 24.

24. Reconnect the right rear power window switch 14P connector.

25. Clear the DTCs with the HDS.

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

27. Operate the right rear power window switch in each direction.

28. Check for DTCs with the HDS.

Is DTC B2187 indicated?

YES -

Replace the right rear power window switch Passenger's Power Window Switch Test/Replacement.

NO -

Go to step 29.

29. Reconnect the left rear power window switch 14P connector.

30. Clear the DTCs with the HDS.

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

32. Operate the left rear power window switch in each direction.

33. Check for DTCs with the HDS.

Is DTC B2187 indicated?

YES -

Replace the left rear power window switch Passenger's Power Window Switch Test/Replacement.

NO -

Go to step 34.

34. Reconnect the moonroof motor/control unit 8P connector.

35. Clear the DTCs with the HDS.

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

37. Open and close the moonroof with the moonroof switch.

38. Check for DTCs with the HDS.

Is DTC B2187 indicated?

YES -

Replace the moonroof motor/control unit Service and Repair.

NO -

Replace the driver's MPCS unit.