DTC B1846: Power Seat Front Up-Down Switch Circuit Malfunction

WARNING: This page is about a different car, the 2009 Acura MDX, 2008 Acura MDX, and 2007 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 ON (II).
Operate the front up-down switch in each direction for more than 1 second.
Check for DTCs with the HDS.
Is DTC B1846 indicated?

YES - Go to step 5.

NO - Intermittent failure, the system is OK at this time. Check for loose or poor connections.
Turn the ignition switch to LOCK (0).
Disconnect power seat control unit connector A (40P).
Disconnect the power seat adjustment switch 12P connector.
Check for continuity between body ground and power seat control unit connector A (40P) No. 1, No. 4, and No. 5 terminals individually.

Fig 1: Identifying Continuity Between Body Ground And Power Seat Control Unit Connector A (40P) No. 1, No. 4, And No. 5 Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Repair short to ground in the wire.

NO - Go to step 9.
Check for continuity between these power seat control unit connector A (40P) terminals:
- No. 1 and No. 4
- No. 1 and No. 5
- No. 4 and No. 5
  
  Fig 2: Identifying Continuity Between These Power Seat Control Unit Connector A (40P) Terminals
  Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?

YES - Repair short in the wire.

NO - Go to step 10.
Test the power seat adjustment switch (see POWER SEAT ADJUSTMENT SWITCH TEST/REPLACEMENT ).
Is the switch OK?

YES - Replace the power seat control unit.

NO - Replace the power seat adjustment switch.