Inspection Procedure
3: The system cannot be activated or deactivated even when the sonar switch is pressed.
caution
Before replacing
the ECU or sensor, ensure that the power supply circuit, the earth circuit and the communication
circuit are normal.
When the illuminated licence plate is installed, the sensors may not operate because
of noise from the plate. (When the ultrasonic noise is received, the bass toned buzzer sound
continuously. When the ultrasonic noise stops, the normal operation will be resumed immediately.)
COMMENTS ON TROUBLE SYMPTOM
If the reversing sensor system ON/OFF cannot be switched even when the sonar
switch is pressed, the harness, connector(s), sonar switch, or corner sensor/back sensor-ECU
may have a problem.
PROBABLE CAUSES
Damaged harness wires and connectors
Malfunction of sonar switch
Malfunction of corner sensor/back sensor-ECU
DIAGNOSIS PROCEDURE
STEP 1. sonar switch check
Inspect the corner sensor switch for normal operation. (Refer to )
Q.
Is the check result normal?
Go to Step 2.
Replace the sonar switch.
STEP 2. Resistance measurement at sonar switch connector (earth terminal)
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between the sonar switch connector (earth terminal) and
body earth. OK: Continuity exists (2 Ω or less)
Q.
Is the check result normal?
Go to Step 4.
Go to Step 3.
STEP 3. Check of open circuit in earth line sonar switch connector
and the body earth
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 ).
Repair the connector(s) or wiring harness.
STEP 4. Check of short to power supply, short to earth, and open circuit
in SW line between sonar switch connector and corner sensor/back sensor-ECU connector