Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Optical sensor System Inspection
- CHECK OPTICAL SENSOR INPUT SIGNAL
With CONSULT-II
Select "BCM" on CONSULT-II. With "HEAD LAMP" data monitor, make sure "OPTICAL SENSOR", check difference in the voltage when auto light sensor is illuminated and not illuminated.
- Illuminated
- OPTICAL SENSOR: 3.1 V or more
- Not illuminated
- OPTICAL SENSOR: 0.6V or less
CAUTION: Optical sensor must be securely subjected to work lamp light. If optical sensor is insufficiently illuminated, the measured value may not satisfy the standard.Without CONSULT-II
- Turn ignition switch ON.
- Check voltage between BCM harness connector M3 terminal 14 (P) and ground.
- Illuminated
- OPTICAL SENSOR: 3.1 V or more
- Not illuminated
- OPTICAL SENSOR: 0.6V or less
CAUTION: Optical sensor must be securely subjected to work lamp light. If optical sensor is insufficiently illuminated, the measured value may not satisfy the standard.OK or NG
- OK: INSPECTION END
- NG: GO TO 2.
- CHECK OPTICAL SENSOR POWER SUPPLY CIRCUIT
- Turn ignition switch OFF.
- Disconnect BCM connector and optical sensor connector.
- Check continuity (open circuit) between BCM harness connector M3 terminal 17 (Y/G) and optical sensor harness connector M37 terminal 1 (Y/G).
- 17 (Y/G) - 1 (Y/G): Continuity should exist.
- Check continuity (short circuit) between BCM harness connector M3 terminal 17 (Y/G) and ground.
- 17 (Y/G) - Ground: Continuity should not exist.
OK or NG
- OK: GO TO 3.
- NG: Repair harness or connector.
- CHECK OPTICAL SENSOR SIGNAL CIRCUIT
- Check continuity (open circuit) between BCM harness connector M3 terminal 14 (P) and optical sensor harness connector M37 terminal 2 (P).
- 14 (P) - 2 (P): Continuity should exist.
- Check continuity (short circuit) between BCM harness connector M3 terminal 14 (P) and ground.
- 14 (P) - Ground: Continuity should not exist.
OK or NG
- OK: GO TO 4.
- NG: Repair harness or connector.
- Check continuity (open circuit) between BCM harness connector M3 terminal 14 (P) and optical sensor harness connector M37 terminal 2 (P).
- CHECK OPTICAL SENSOR GROUND CIRCUIT
- Check continuity (open circuit) between BCM harness connector M3 terminal 18 (B) and optical sensor harness connector M37 terminal 3 (B).
- 18 (B) - 3 (B): Continuity should exist.
- Check continuity (short circuit) between BCM harness connector M3 terminal 18 (B) and ground.
- 18 (B) - Ground: Continuity should not exist.
OK or NG
- OK: GO TO 5.
- NG: Repair harness or connector.
- Check continuity (open circuit) between BCM harness connector M3 terminal 18 (B) and optical sensor harness connector M37 terminal 3 (B).
- CHECK OPTICAL SENSOR VOLTAGE
- Connect BCM connector.
- Turn ignition switch ON.
- Check voltage between BCM harness connector M3 terminal 17 (Y/G) and ground.
- 17 (Y/G) - Ground: Approx. 5V
OK or NG
- OK: Replace optical sensor.
- NG: Replace BCM. Refer to "REMOVAL AND INSTALLATION OF BCM ".
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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