Inspection Procedure 1: The system is not turned on and off by operating the LDW switch.


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

COMMENTS ON TROUBLE SYMPTOM


If the system is not turned on and off by operating the LDW switch, the ETACS-ECU or the FCM/LDW/AHB-ECU may be defective.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE


STEP 1. M.U.T.-III other system data list.


Using the ETACS-ECU data list, check the LDW switch signal.

Item No.
 Item name
 Normal condition
Item 405
 LDW switch
 ON

Item No.
 Item name
 Normal condition
Item 405
 LDW switch
 OFF
OK: Normal condition is displayed.

Q. Is the check result normal?

Go to Step 2.

NO : Go to Step 4.

STEP 2. M.U.T.-III data list.


Check the FCM/LDW/AHB-ECU data list (Refer to ).

Item No.
 Item name
 Normal condition
Item 26
 LDW switch
 ON

Item No.
 Item name
 Normal condition
Item 26
 LDW switch
 OFF
OK: Normal condition is displayed.

Q. Is the check result normal?

Go to Step 3.

Replace the FCM/LDW/AHB-ECU (Refer to ).

STEP 3. Retest the system.


Check whether system is turned on and off by operating the LDW switch.

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 FCM/LDW/AHB-ECU (Refer to ).

STEP 4. Check of short to earth, and open circuit in LDW SW(S+) line between ETACS-ECU connector and LDW switch connector.


Q. Is the check result normal?

Go to Step 5.

Repair the connector(s) or wiring harness.

STEP 5. Check of open circuit in LDW SW(S-) line between LDW switch connector and body earth.


Q. Is the check result normal?

Go to Step 6.

Repair the connector(s) or wiring harness.

STEP 6. Check the LDW switch.


Check the LDW switch (Refer to ).

Q. Is the check result normal?

Go to Step 7.

Replace the LDW switch (Refer to ).

STEP 7. M.U.T.-III other system data list.


Using the ETACS-ECU data list, check the LDW switch signal.

Item No.
 Item name
 Normal condition
Item 405
 LDW switch
 ON

Item No.
 Item name
 Normal condition
Item 405
 LDW switch
 OFF
OK: Normal condition is displayed.

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).

NO : Replace the ETACS-ECU.