B2187

DTC B2187: Communication Line (UART Line) Circuit Short

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

1. Clear the DTCs with the HDS.
2. Turn the ignition switch OFF and then back ON (II).
3. Operate the front passenger's, left rear and right rear 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 OFF.
6. Disconnect these connectors:
- Driver's MPCS unit connector A (40P)
- Power window master switch 6P connector
- Passenger's MPCS unit connector A (28P)
- Left window switch 14P connector
- Right 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.

If there continuity?

YES - Repair a short to ground in the wire.

NO - Go to step 8.

8. Turn the ignition switch ON (II).
9. Clear the DTCs with the HDS.
10. Turn the ignition switch OFF and then back ON (II).
11. Wait for 6 seconds or more.
12. Check for DTCs with the HDS.

Is DTC B2187 indicated?

YES - Replace the driver's MPCS unit.

NO - Go to step 13.

13. Reconnect the power window master switch 6P connector.
14. Clear the DTCs with the HDS.
15. Turn the ignition switch OFF and then back ON (II).
16. Operate each switch of the power window master switch.
17. Check for DTCs with the HDS.

Is DTC B2187 indicated?

YES - Replace the power window master switch.

NO - Go to step 18.

18. Reconnect the passenger's MPCS unit connector A (28P).
19. Clear the DTCs with the HDS.
20. Turn the ignition switch OFF and then back ON (II).
21. Operate the front passenger's window switch in each direction.
22. Check for DTCs with the HDS.

Is DTC B2187 indicated?

YES - Replace the passenger's MPCS unit

NO - Go to step 23.

23. Reconnect the right rear window switch 14P connector.
24. Clear the DTCs with the HDS.
25. Turn the ignition switch OFF and then back ON (II).
26. Operate the right rear window switch in each direction.
27. Check for DTCs with the HDS.

Is DTC B2187 indicated?

YES - Replace the right rear window switch.

NO - Go to step 28.

28. Reconnect the left rear window switch 14P connector.
29. Clear the DTCs with the HDS.
30. Turn the ignition switch OFF and then back ON (II).
31. Operate the left rear window switch in each direction.
32. Check for DTCs with the HDS.

Is DTC B2187 indicated?

YES - Replace the left rear window switch.

NO - Go to step 33.

33. Reconnect the moonroof motor/control unit 8P connector.
34. Clear the DTCs with the HDS.
35. Turn the ignition switch OFF and then back ON (II).
36. Open and close the moonroof with the moonroof switch.
37. Check for DTCs with the HDS.

Is DTC B2187 indicated?

YES - Replace the moonroof motor/control unit

NO - Replace the driver's MPCS unit.