DTC B1843: Power Seat Control Unit Lost Communication with Power Tilt/Telescopic Steering Control Unit (UART line)
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).
- 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.
- Move the tilt/telescopic steering in each direction with the tilt/telescopic switch.
Does the tilt/telescopic steering move in each direction smoothly?
YES - Go to step 5.
NO - Go to step 10.
- Turn the ignition switch to LOCK (0).
- Disconnect power seat control unit connector A (40P).
- Disconnect power tilt/telescopic control unit connector A (16P).
- Check for continuity between power seat control unit connector A (40P) No. 39 terminal and power tilt/telescopic control unit connector A (16P) No. 11 terminal.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES - Go to step 9.
NO - Repair open in the wire.
- Check for continuity between power seat control unit connector A (40P) No. 39 terminal and body ground.Fig 2: Identifying Continuity Between Power Seat Control Unit Connector A (40P) No. 39 Terminal And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES - Repair short in the wire.
NO - Substitute a known-good power tilt/telescopic control unit and recheck. If DTC B1843 is still indicated, replace the power seat control unit.
- Turn the ignition switch to LOCK (0).
- Disconnect power tilt/telescopic control unit connectors A (16P) and B (8P).
- Turn the ignition switch ON (II).
- Measure the voltage between power tilt/telescopic control unit connector A (16P) No. 9 terminal and connector B (8P) No. 1 terminal, and between connector A (16P) No. 1 terminal and connector B (8P) No. 1 terminal.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there battery voltage?
YES - Replace the power tilt/telescopic control unit.
NO - Do the power tilt/telescopic control unit input test (see POWER TILT/TELESCOPIC STEERING CONTROL UNIT INPUT TEST ).