B1848
DTC B1848: Rear Headrest Switch Signal ErrorNOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A.
1. Clear the DTCs with the HDS.
2. Turn the ignition switch OFF, and then back ON (II).
3. Retract the rear headrests with the headrest switch.
4. Check for DTCs with the HDS.
Is DTC B1848 indicated?
YES - Go to step 5.
NO - Intermittent failure, the rear headrest system is OK at this time. Check for loose or poor connections.
5. Turn the ignition switch OFF.
6. Disconnect power seat control unit connector A (40P).
7. Disconnect the roof console 28P connector.
8. Check for continuity between body ground and power seat control unit connector A (40P) terminals No. 1 and No. 22 individually.
Is there continuity?
YES - Repair a short to ground in the wire.
NO - Go to step 9.
9. Check for continuity between power seat control unit connector A (40P) terminals No. 1 and No. 22.
Is there continuity?
YES - Repair a short in the wire.
NO - Go to step 10.
10. Reconnect the 28P connector to the roof console.
11. Check for continuity between power seat control unit connector A (40P) terminals No. 1 and No. 22 without pressing the headrest switch.
Is there continuity?
YES - Faulty headrest switch, replace the roof console.
NO - Go to step 12.
12. Disconnect the roof console 28P connector.
13. Check for continuity between roof console 28P connector terminals No. 9 and No. 10 and roof console body ground.
Is there continuity?
YES - Faulty headrest switch, replace the roof console.
NO - Go to the power seat control unit input test. Power Seat Control Unit Input Test