Check it by the procedure below to see if the function of the ECM is normal.
Turn the ignition key to the "ON" position.
Cover the front looking sensor (D) to stop functioning.
Shed a light to the rearward looking sensor (B).
The ECM should be darkened as soon as the rearward looking sensor detects the glaring of the light.
If this test is performed in daytime, the ECM may be darkened as soon as the front looking sensor is covered.
When the reverse gear is engaged, the ECM should not be darkened.
When shedding lights to both the front looking and rearward looking sensors, the ECM should not be darkened.
