DTC B1843: UART Communication Error
WARNING: This page is about a different car, the 2011 Honda Pilot, 2010 Honda Pilot, and 2009 Honda Pilot. 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).
- Operate the power seat with the driving position memory switch
- Check for DTCs with the HDS
Is DTC B1843 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 the power seat control unit connectors and power mirror control unit connector (24P)..
- Check for continuity between power seat control unit connector B (40P) terminal No. 38 and power mirror control unit connector (24P) terminal No. 13.
Is there continuity?
YES - Go to step 8
NO - Repair a short to ground in the UART wire.
- Check for continuity between power seat control unit connector B (40P) terminal No. 38 and body ground.
Is there continuity?
YES - Repair a short to ground in the UART wire.
NO - Go to step 9
- Reconnect the power mirror control unit connector (24P).
- Turn the ignition switch to ON (II).
- Measure the voltage between body ground and power mirror control unit connector (24P) terminal No. 24.
Is there continuity?
YES - YES - Go to step 12.
NO - Check the No. 23 (10 A) fuse in the under-hood fuse/relay box. If the fuse is OK, repair an open or high resistance in the wire.
- Measure the voltage between power mirror control unit connector (24P) terminal No. 22 and body ground.
Is there 0.2 V or more?
YES - Repair an open or high resistance in the wire between the power mirror control unit and G401. If the wire is OK, repair G401. ■
NO - Replace the power mirror control unit. ■