Inspection Procedure 1: The Front Fog Lamps do not Illuminate Normally.


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




OPERATION


The ETACS-ECU operates this function in accordance with the input signals below.

If the front fog lamps do not illuminate normally, these input signal circuit(s) or the ETACS-ECU may be defective.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE


STEP 1. Check that the tail lamps and headlamps operate.


Check that the tail lamps and headlamps illuminate normally.

Q. Is the check result normal?

Go to Step 2.

Check the tail lamps and the headlamps (Refer to trouble symptom chart <tail lamp>, <headlamp>).

STEP 2. ECU check by using the SWS monitor


Check that the power supply and earth lines to the column switch (column-ECU), the ETACS-ECU and the front-ECU and the SWS communication lines are normal.

ECUS TO BE CHECKED
OK: "OK" are displayed for all the items

Q. Is the check result normal?

YES ("OK" are displayed for all the items) : Go to Step 3.

NO ("NG" is displayed on the "COLUMN ECU" menu) : Refer to GROUP 54C - Trouble Symptom Chart .

NO ("NG" is displayed on the "ETACS ECU" menu) : Refer to GROUP 54C - Trouble Symptom Chart .

NO ("NG" is displayed on the "FRONT ECU" menu) : Refer to GROUP 54C - Trouble Symptom Chart .

STEP 3. Function diagnosis by using the SWS monitor


Check the SWS communication signal, which are related to the front fog lamps.
<Selected item> LIGHTING - F.FOG LAMP
Item No.
 Item name
 Normal condition
Item 00
 HEADLAMP SW
 ON when the lighting switch is at HEAD
Item 01
 TAIL LAMP SW
 ON when the lighting switch is at TAIL or HEAD
Item 30
 IG SW(IG1)
 ON
Item 36
 F.FOG LAMP
 ON
Item 70
 FRONT ECU ACK
 NORMAL ACK or HI-BEAM ACK
OK: Normal conditions are displayed for all the items.

Q. Is the check result normal?

YES (Normal conditions are displayed for all the items) : Go to Step 4.

NO (Normal condition is not displayed for item 00 or 01) : Refer to ETACS - Input Signal Chart .

NO (Normal condition is not displayed for item No.30) : Refer to ETACS - Input Signal Chart .

NO (Normal condition is not displayed for item No.36) : Refer to ETACS - Input Signal Chart .

NO (Normal condition is not displayed for item No.70) : Replace the front-ECU.

STEP 4. Connector check: A-07X front fog lamp relay connector.


Q. Is the check result normal?

Go to Step 5.

Repair the defective connector.

STEP 5. Check the front fog lamp relay.


Refer to front fog lamp relay check .

Q. Is the check result normal?

Go to Step 6.

Replace the front fog lamp relay.

STEP 6. Voltage measurement at the A-07X front fog lamp relay connector.


(1)Remove the front fog lamp relay, and measure at the relay box side.
(2)Check the voltage between the front fog lamp relay connector and body earth.

  • Voltage between A-07X front fog lamp relay connector terminal No.3 and body earth
  • Voltage between A-07X front fog lamp relay connector terminal No.4 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 A-07X front fog lamp relay connector (terminal Nos.3 and 4) and the battery.



Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

STEP 8. Connector check: A-08X front-ECU connector


Q. Is the check result normal?

Go to Step 9.

Repair the defective connector.

STEP 9. Check the wiring harness between A-07X front fog lamp relay connector terminal No.1 and A-08X front-ECU connector terminal No.1.



Q. Is the check result normal?

Go to Step 10.

Repair the wiring harness.

STEP 10. Retest the system.


Check that the front fog lamps illuminate normally.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

Replace the ETACS-ECU.