B2647

CONDITIONS FOR SETTING THE DTC
^ An open in the ambient light sensor circuit.
^ A short to ground in the ambient light sensor circuit.
^ Condition must be present for 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ Stores a DTC B2647 in the BCM memory.
^ The automatic headlamps and park lamps will remain ON.

CONDITIONS FOR CLEARING THE DTC
^ The BCM no longer detects an open or short to ground in the ambient light sensor circuit.
^ A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.
^ Use the IPC clearing DTCs feature.
^ The BCM receives the Clear Code command from the scan tool.

DIAGNOSTIC AIDS
^ The following conditions may cause an intermittent malfunction:
- An intermittent short to ground in the ambient light sensor reference circuit.
- An intermittent open in the ambient light sensor signal circuit.
- The ambient light sensor is shorted or open internally.
^ If the ambient light sensor circuit is open or shorted (to ground or voltage) the BCM will command the automatic headlamps and park lamps ON. If the ignition is cycled the BCM will retest for any malfunctions in the ambient light sensor circuit and if a malfunction is current the BCM will activate the automatic.
^ If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.

TEST DESCRIPTION

Steps 1-3:

Steps 4-14:

The number(s) below refer to the step number(s) on the diagnostic table.
2. Tests ambient light sensor data using a scan tool.
3. Tests the ambient light sensor data with the sensor disconnected. The scan tool will display ambient light sensor voltage as 0 volts with the sensor disconnected.
4. Tests the ambient light sensor data with a jumper wire between the reference and signal circuit. The scan tool will display ambient light sensor voltage between 3.5-4.5 volts with the sensor jumpered.
5. Tests for a short to voltage in the 5 volt reference circuit.