DTC B1843: UART Communication Error Honda Pilot II

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 ).

Scheme 74

Scheme 75

Scheme 76

Scheme 77

1. Clear the DTCs with the HDS.
2. Turn the ignition switch to LOCK (0), and then back to ON (II).
3. Operate the power seat with the driving position memory switch
4. 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.
5. Turn the ignition switch to LOCK (0).
6. Disconnect the power seat control unit connectors and power mirror control unit connector (24P)..
7. 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.
8. 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
9. Reconnect the power mirror control unit connector (24P).
10. Turn the ignition switch to ON (II).
11. 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.
12. 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.