( TL19E00K733000Y1230FAAT00 )

DTC Troubleshooting: B1230 (F and AUTO)

1. Check for continuity between heater control unit connector A (28P) No. 25 terminal and heater control unit connector B (12P) No. 10 terminal.

Is there continuity?

YES | - | Repair short in the wires between the heater control unit and the sunlight sensor.■
NO | - | Go to Step 10 .

1. Reconnect the sunlight sensor 2P connector.

1. Reconnect heater control unit connectors A (28P)and B (12P).

1. Test the sunlight sensor.

Is the sunlight sensor OK?

YES | - | Substitute a known-good heater control unit, and recheck. If the symptom/indication goes away, replace the original heater control unit .■
NO | - | Replace the sunlight sensor. ■