Inspection Procedure 7: Daytime Running Lamp Function does not Work Normally. <Not Using SWS Monitor>


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






COMMENTS ON TROUBLE SYMPTOM
If the daytime running lamp function is not operating normally the ETACS-ECU power circuit may be defective or the ETACS-ECU may be defective.

PROBABLE CAUSES

  • The ETACS-ECU may be defective
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Check that the headlamps operate.
Do the low-beam headlamps illuminate when the lighting switch is turned to the HEAD position?

Q. Is the check result normal?
Go to Step 2.
First, repair the headlamps. Refer to Inspection Procedure 2 "The low-beam headlamps do not illuminate normally ."

STEP 2. Check the power supply circuit.
When the ignition switch is turned to the LOCK (OFF) position, check if the hazard warning lamps illuminate.

Q. Is the check result normal?
Go to Step 3.
Refer to ETACS - inspection procedure 1 "Check the battery power supply circuit to the ETACS-ECU ."

STEP 3. Pulse check
Check the input signals below, which are related to the daytime running lamp function.
System switch
 Check condition
Ignition switch (IG1)
 When turned from ACC to ON
OK: The M.U.T.-III sounds or the voltmeter needle fluctuates.

Q. Is the check result normal?
Go to Step 4.
Refer to ETACS - Input Signal Chart .

STEP 4. Connector check: D-420 ETACS-ECU connector.

Q. Is the check result normal?
Go to Step 5.
Repair the defective connector.

STEP 5. Resistance measurement at the D-420 ETACS-ECU connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Check the resistance between the ETACS-ECU connector and body earth.

  • Resistance between D-420 ETACS-ECU connector terminal No.64 and body earth
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Replace the ETACS-ECU.
Go to Step 6.

STEP 6. Check the wiring harness from D-420 ETACS-ECU connector terminal No.64 to body earth.
note Prior to the wiring harness inspection, check jumper connector D-01, and repair if necessary.

  • Check the earth wires for open circuit.

Q. Is the check result normal?
Replace the ETACS-ECU.
Repair the wiring harness.