DTC B2186: Front Passenger's Door Lock Switch LOCK/UNLOCK Signal Error

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

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 to ON (II).
Lock and unlock the front passenger's door with the front passenger's door lock switch.
Check for DTCs with the HDS.
Is DTC B2186 indicated?

YES -Go to step 5.

NO -Intermittent failure, the front passenger's door lock switch system is OK at this time. Check for loose or poor connections between the front passenger's MPCS unit and the front passenger's door lock switch.
With the front passenger's door lock switch in the neutral position, select KEYLESS TRANSMITTER from the BODY ELECTRICAL SYSTEM SELECT menu, and enter DATA LIST.
Check the ON/OFF information of the Front Passenger's Door Lock Switch (LOCK) and Front Passenger's Door Lock Switch (UNLOCK).
Are both information indicators OFF?

YES -Go to step 7.

NO -Go to step 8.
Operate the front passenger's door lock switch in the LOCK and UNLOCK positions, and check the ON/OFF information of the Front Passenger's Door Lock Switch (LOCK) and Front Passenger's Door Lock Switch (UNLOCK).
Are both the Front Passenger's Door Lock Switch (LOCK) and Front passenger's Door Lock Switch (UNLOCK) information indicators ON at the same time when the door lock switch is in the LOCK or UNLOCK position?

YES -Do the door lock switch test (see Door Lock Switch Test ). If the switch is OK, repair a short between the wires.

NO -Replace the front passenger's MPCS unit.
Disconnect the front passenger's door lock switch 5P connector.
Check the ON/OFF information of the Front Passenger's Door Lock Switch (LOCK) and Front Passenger's Door Lock Switch (UNLOCK).
Are both information indicators OFF?

YES -Replace front passenger's door lock switch.

NO -Go to step 10.
Turn the ignition switch to LOCK (0).
Disconnect front passenger's MPCS unit connector A (28P).
Check for continuity between body ground and front passenger's door lock switch 5P connector terminals No. 3 and No. 4 individually.

Fig 1: Checking For Continuity Between Body Ground And 5P Connector Terminals No. 3 And No. 4
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair a short to ground in the wire.

NO -Replace the front passenger's MPCS unit.