Code No.U0231 Rain light sensor LIN timeout <Vehicles with lighting control sensor>

caution Before replacing the ECU, ensure that the communication circuit is normal.



  • Faulty lighting control sensor
  • Malfunction of the LIN bus


STEP 1. Connector check: C-316 ETACS-ECU connector, D-131 lighting control sensor connector

Q. Is the check result normal?

Go to Step 2.
Repair the defective connector.

STEP 2. Check the wiring harness wires between C-316 ETACS-ECU connector terminal No. 1 and D-131 lighting control sensor connector terminal No. 3.

Check the communication lines for open circuit.

Q. Is the check result normal?

Go to Step 3.
Repair the wiring harness.

STEP 3. Check whether the diagnosis code is reset.

Check again if the diagnosis code is set to the ETACS-ECU.
(1)Erase the diagnosis code.
(2)Turn the ignition switch from the LOCK (OFF) position to the ON position.
(3)Check if diagnosis code is set.

Q. Is the diagnosis code set?

Replace the lighting control sensor.
A poor connection, open circuit, or other intermittent malfunctions in the LIN bus lines between the lighting control sensor and the ETACS-ECU (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).