Inspection Procedure 1: The Diagnosis Code is not Set.


caution Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.














COMMENTS ON TROUBLE SYMPTOM



PROBABLE CAUSES



  • Malfunction of the headlamp automatic levelling-ECU
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE


STEP 1. Connector check: C-14 headlamp automatic levelling-ECU connector


Q. Is the check result normal?





STEP 2. Resistance measurement at the C-14 headlamp automatic levelling-ECU connector.


(1)Disconnect the connector, and measure the resistance at the wiring harness-side connector.
(2)Measure the resistance between the C-14 headlamp automatic levelling-ECU connector terminal No. 14 and the body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?





STEP 3. Wiring harness check between the C-14 headlamp automatic levelling-ECU connector terminal No. 14 and the body earth



  • Check the earth wires for open circuit.

Q. Is the check result normal?


    Go to Step 4.



STEP 4. Voltage measurement at the C-14 headlamp automatic levelling-ECU connector.


(1)Disconnect the connector, and measure at the wiring harness-side connector.
(2)Turn the ignition switch to the ON position.
(3)Voltage between the C-14 headlamp automatic levelling-ECU connector terminal No. 1 and the body earth
OK: System voltage

Q. Is the check result normal?





STEP 5. Wiring harness check between the C-14 headlamp automatic levelling-ECU connector terminal No. 1 and the fusible link (34) <1500, 1800, 2000-PETROL> or (44) <2000-DIESEL>


note Before the wiring harness check, check the ETACS-ECU connectors C-309 and C-317, and the intermittent connector C-128. Then, repair them if necessary.

  • Check the power supply line for open circuit.

Q. Is the check result normal?





STEP 6. Connector check: C-26 diagnosis connector


Q. Is the check result normal?





STEP 7. Wiring harness check between the C-14 headlamp automatic levelling-ECU connector terminal No. 5/7 and the C-26 diagnosis connector terminal No. 1/10


note Before the wiring harness check, check the intermittent connectors C-127 and C-128, and then repair that if necessary.

  • Check the communication lines for open circuit and short circuit.

Q. Is the check result normal?





STEP 8. Retest the system



Q. Is the diagnosis code set?