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Home >> Acura >> 2011 >> RDX 2.3 TB2 >> Repair and Diagnosis >> Body & Frame >> Seats >> Driver Position Memory System (DPMS) >> DTC Troubleshooting >> DTC B1843: UART Communication Error
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DTC B1843: UART Communication Error

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 ).
  1. Clear the DTCs with the HDS.
  2. Turn the ignition switch to LOCK (0) and then back to ON (II).
  3. Check for DTCs with the HDS.

    Is DTC B1843 indicated? 

    YES  -Go to step 4.

    NO  -Intermittent failure, the system is OK at this time. Check for loose or poor connections.

  4. Move the power mirrors in each direction with the power mirrors switch.

    Do the power mirrors move in each direction smoothly? 

    YES  -Go to step 5.

    NO  -Go to step  10.

  5. Turn the ignition switch to LOCK (0).
  6. Disconnect power seat control unit connector A (40P).
  7. Disconnect the power mirror control unit 24P connector.
  8. Check for continuity between power seat control unit connector A (40P) terminal No. 39 and power mirror control unit connector (24P) terminal No. 13 respectively.
    Fig 1: Checking Continuity Between Power Seat Control Unit Connector A (40P) Terminal 39 And Mirror Control Unit Connector (24P) Terminal 13
    G08061470Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 9.

    NO  -Repair open or high resistance in the wire.

  9. Check for continuity between power seat control unit connector A (40P) terminal No. 39 and body ground.
    Fig 2: Checking Continuity Between Power Seat Control Unit Connector A (40P) Terminal No. 39 And Body Ground
    G08061471Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair short to ground in the wire.

    NO  -Substitute a known-good power mirror control unit and recheck. If DTC B1843 is still indicated, replace the power seat control unit (see POWER SEAT CONTROL UNIT INPUT TEST/REPLACEMENT  ).

  10. Turn the ignition switch to LOCK (0).
  11. Disconnect the power mirror control unit 24P connector.
  12. Turn the ignition switch to ON (II).
  13. Measure the voltage between the power mirror control unit 24P connector terminals No. 11 and No. 22 and between terminals No. 24 and No. 22 respectively.
    Fig 3: Measuring Voltage Between Power Mirror Control Unit 24P Connector Terminals 11 And Between Terminals 24
    G08061472Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Replace the power mirror control unit.

    NO  -Repair an open or high resistance in the wire.

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