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.

Tail lamp switch
Headlamp switch
Fog lamp switch

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

PROBABLE CAUSES

Malfunction of the column switch
Malfunction of the fog lamp switch
Malfunction of the ETACS-ECU
Damaged harness wires and connectors

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. Pulse check

Check the input signals below, which are related to the front fog lamps.

System switch	Check condition
Ignition switch (IG1)	When turned from ACC to ON
Tail lamp switch	When the lighting switch is turned to the TAIL position
Headlamp switch	When the lighting switch is turned to the HEADLAMP position
Front fog lamp switch	When the front fog lamp switch is turned from off to on

OK: The M.U.T.-III sounds or the voltmeter needle fluctuates.

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 ETACS - Input Signal Chart

.

NO (The tail lamp switch signal is not received) : Refer to ETACS - Input Signal Chart

.

NO (The headlamp switch signal is not received) : Refer to ETACS - Input Signal Chart

.

NO (The front fog lamp switch signal is not received) : Refer to ETACS - Input Signal Chart

STEP 3. Connector check: A-07X front fog lamp relay connector.

Q. Is the check result normal?

Go to Step 4.

Repair the defective connector.

STEP 4. Check the front fog lamp relay.

Refer to front fog lamp relay check

Q. Is the check result normal?

Go to Step 5.

Replace the front fog lamp relay.

STEP 5. 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 7.

Go to Step 6.

STEP 6. Check the wiring harness between A-07X front fog lamp relay connector (terminal Nos.3 and 4) and the battery.

Check the power supply line for open circuit.

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 7. Connector check: A-08X front-ECU connector

Q. Is the check result normal?

Go to Step 8.

Repair the defective connector.

STEP 8. Check the wiring harness between A-07X front fog lamp relay connector terminal No.1 and A-08X front-ECU connector terminal No.1.

Check the output lines for open circuit.

Q. Is the check result normal?

Go to Step 9.

Repair the wiring harness.

STEP 9. 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.