B2647

DTC B2647

CIRCUIT DESCRIPTION
The ambient light sensor indicates the light level to control the automatic headlamps and park lamps. The body control module (BCM) provides a 5-volt reference signal to the light sensor. The BCM receives the modified voltage from the ambient light sensor through the ambient light sensor low reference circuit. A low voltage under 1.5 volts, signals a dark condition to the BCM and vice versa.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC B2647 Ambient Light Sensor Circuit Low

CONDITIONS FOR RUNNING THE DTC
The ignition switch is in the RUN position.

CONDITIONS FOR SETTING THE DTC
The daytime running lamps (DRL)/ambient light sensor signal circuit is shorted to ground for 5 seconds.

ACTION TAKEN WHEN THE DTC SETS
The DRL and indicator will not illuminate.

CONDITIONS FOR CLEARING THE DTC
- The BCM receives the clear code command from the scan tool.
- A current DTC will clear when the conditions for setting the DTC are no longer present.
- A history DTC clears after 100 malfunction free ignition cycles.

DIAGNOSTIC AIDS
If the DTC is a history DTC, the problem may be intermittent.

TEST DESCRIPTION

Step 1 - Step 9:

The numbers below refer to the step numbers on the diagnostic table.
2. The normal operating voltage of the ambient light sensor, photocell, is 0.5-4.5 volts.
3. This step determines if there is a problem with the signal circuit of the ambient light sensor.