Inspection Procedure 3: The system is not turned on and off by operating the blind spot warning 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 blind spot warning switch, a circuit (among the gateway-ECU, the blind spot warning lamp and earth), the gateway-ECU, or the BSW-ECU (master) may be defective.
note Prior to diagnosis, check the power supply circuit to the gateway-ECU. If no faults are detected, follow this troubleshooting procedure.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE


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


Using the gateway-ECU data list, check the blind spot warning switch signal.

Item No.
 Item name
 Normal condition
Item 5
 BSW switch
 ON

Item No.
 Item name
 Normal condition
Item 5
 BSW switch
 OFF
OK: Normal condition is displayed.

Q. Is the check result normal?

Go to Step 6.

NO : Go to Step 2.

STEP 2. Check of short to earth, and open circuit in DI05 line between gateway-ECU and blind spot warning switch connector.


Q. Is the check result normal?

Go to Step 3

Repair the connector(s) or wiring harness.

STEP 3. Check of open circuit between blind spot warning switch connector earth terminal and body earth


Q. Is the check result normal?

Go to Step 4

Repair the connector(s) or wiring harness.

STEP 4. Blind spot warning switch check


Refer to .

Q. Is the check result normal?

Go to Step 5

Replace the blind spot warning switch.

STEP 5. M.U.T.-III other system data list


Using the gateway-ECU data list, check the blind spot warning switch signal.

Item No.
 Item name
 Normal condition
Item 5
 BSW switch
 ON

Item No.
 Item name
 Normal condition
Item 5
 BSW switch
 OFF
OK: Normal condition is displayed.

Q. Is the check result normal?

Go to Step 6

NO : Replace the gateway-ECU.

STEP 6. Retest the system


Check whether the system can be switched on and off by the blind spot warning switch.

Q. Is the check result normal?

Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to cope with Intermittent Malfunction).

Replace the BSW-ECU (master).