DTC B2188: Communication Line (UART Line) Driver's MPCS Unit cannot receive UART messages from Front Passenger's MPCS Unit.

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

Clear the DTCs with the HDS.
Turn the ignition switch to LOCK (0), and then back ON (II).
Open and close the driver's and front passenger's windows by operating the power window master switch.
Check for DTCs with the HDS.
Is DTC B2188 indicated?

YES - Go to step 5.

NO - Intermittent failure, the system is OK at this time.
Turn the ignition switch to LOCK (0).
Disconnect driver's MPCS unit connector A (40P).
Disconnect front passenger's MPCS unit connector A (28P).
Check for continuity between the driver's MPCS unit connector A (40P) No. 8 terminal and the front passenger's MPCS unit connector A (28P) No. 4 terminal.

Fig 1: Identifying Continuity Between Driver's MPCS Unit A (40P) Connector Terminal 8
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Substitute a known-good driver's MPCS unit and recheck. If the DTC goes away, replace the original driver's MPCS unit. If the DTC is still present, replace the front passenger's MPCS unit.

NO - Repair open in the wire.