B1843

DTC Troubleshooting: B1843

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 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 at the power seat control unit.

4. 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.

5. Turn the ignition switch to LOCK (0).

6. Disconnect power seat control unit connector A (40P).

7. Disconnect power tilt/telescopic steering control unit connector A (16P).

8. Check for continuity between power seat control unit connector A (40P) terminal No. 39 and power tilt/telescopic steering control unit connector A (16P) terminal No. 11.





Is there continuity?

YES -

Go to step 9.

NO -

Repair an 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.





Is there continuity?

YES -

Repair a short to ground in the wire.

NO -

Substitute a known-good power tilt/telescopic steering control unit, and recheck. If DTC B1843 is still indicated, replace the power seat control unit Power Seat Control Unit Input Test/Replacement.

10. Turn the ignition switch to LOCK (0).

11. Disconnect power tilt/telescopic steering control unit connectors A (16P) and B (8P).

12. Turn the ignition switch to ON (II).

13. Measure the voltage between power tilt/telescopic steering control unit connector A (16P) terminal No. 9 and connector B (8P) terminal No. 1, and between connector A (16P) terminal No. 1 and connector B (8P) terminal No. 1.





Is there battery voltage?

YES -

Replace the power tilt/telescopic steering control unit Testing and Inspection.

NO -

Do the power tilt/telescopic steering control unit input test Testing and Inspection.