Inspection Procedure F-2: The low-beam headlamps do not illuminate normally.


caution Whenever the ECU is replaced, ensure that the input and output signal circuits are normal.


COMMENTS ON TROUBLE SYMPTOM


If the low-beam headlamps do not illuminate, the headlamp switch input circuit, the headlamp relay (LO) or the ETACS-ECU may be defective.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code.
Check that ETACS-ECU sets a diagnosis code.

Q. Is the diagnosis code set?
Refer to diagnosis code chart .
Go to Step 2.

STEP 2. M.U.T.-III data list
Check the input signal from the headlamp (low-beam) switch.
(1)Turn the ignition switch to the "ON" position.
(2)Turn the headlamp (low-beam) switch to the ON position.
Item No.
 Item name
 Normal condition
04
 Low beam lamp
 ON
30
 Ignition Switch (IG1)
 ON
OK: Normal conditions are displayed for all the items.

Q. Is the check result normal?
YES <All the signals are received normally.> : Go to Step 3.
NO <The ignition switch (IG1) signal is not received.> : Refer to inspection procedure J-3 "The ignition switch (IG1) signal is not received ."
NO <The headlamp (low-beam) switch signal is not received.> : Refer to Inspection Procedure J-1 "The column switch (lighting and wiper switch) signal is not received ."

STEP 3. M.U.T.-III actuator test
Perform the actuator test of the ETACS-ECU, and check that the headlamps (low-beam) work normally.

  • Item 03: Head lamp low: OFF
  • Item 04: Head lamp low: ON

Q. Is the check result normal?
Go to Step 9.
Go to Step 4.

STEP 4. Connector check: B-223 headlamp relay (LO) connector


Q. Is the check result normal?

Go to Step 5.

Repair the defective connector.

STEP 5. Check the headlamp relay (LO).
Refer to GROUP 54A - Headlamp .

Q. Is the check result normal?
Go to Step 6.
Replace the headlamp relay (LO).

STEP 6. Voltage measurement at B-223 headlamp relay (LO) connector.


(1)Remove the headlamp relay (LO), and measure at the junction block side.

(2)Voltage between B-223 headlamp relay (LO) connector terminal Nos.1, 3 and body earth
OK: System voltage

Q. Is the check result normal?

Go to Step 8.

Go to Step 7.

STEP 7. Check the wiring harness between B-223 headlamp relay (LO) connector terminal Nos.1, 3 and the fusible link (1).



note Prior to the wiring harness inspection, check the junction block connector B-208, and repair if necessary.

  • Check the power supply line from the fusible link (1) for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

STEP 8. Connector check: B-234 ETACS-ECU connector


Q. Is the check result normal?

Go to Step 9.

Repair the defective connector.

STEP 9. Retest the system.
Check that the low-beam headlamps illuminate normally.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace the ETACS-ECU. Then perform the variant coding and write the VIN data (Refer to GROUP 00, Precautions Before Service - How to Perform Variant Coding ).