Diagnostic Aids

If the DTC B2647 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
The following conditions may cause an intermittent condition to occur:
- An intermittent short to ground in the DRL ambient light sensor signal circuit.
- The ambient light sensor is intermittently shorted to ground.
- The BCM is intermittently shorted to ground.

DTC B2647

Step	Action	Values	Yes	No
Schematic Reference: Interior Lights Schematics Connector End View Reference: Master Electrical Component List
1	Did you perform the Lighting System Diagnostic System Check?	-	Go to Step 2	Go to Diagnostic System Check - Lighting Systems
2	Install a scan tool. Turn ON the ignition, with the engine OFF. Expose the ambient light sensor to a strong incandescent light. With a scan tool, observe the ambient light sensor parameter in the BCM data list. Does the scan tool indicate that the ambient light sensor input parameter is within the specified range?	0.25-2.5 V	Go to Diagnostic Aids	Go to Step 3
3	Turn OFF the ignition. Disconnect the ambient light sensor. Turn ON the ignition, with the engine OFF. With a scan tool, observe the ambient light sensor parameter in the BCM data display - data list. Does the scan tool indicate that the ambient light sensor input parameter is less than the specified value?	0.25 V	Go to Step 5	Go to Step 4
4	Turn OFF the ignition. At the ambient light sensor connector, connect a 3-amp fused jumper wire between the DRL ambient light signal circuit and the DRL ambient light sensor low reference circuit. Turn ON the ignition, with the engine OFF. With a scan tool, observe the ambient light sensor input parameter. Does the scan tool indicate that the ambient light sensor input parameter is less than the specified value?	0.25 V	Go to Step 7	Go to Step 6
5	Test the DRL ambient light sensor signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 11	Go to Step 8
6	Test the DRL ambient light sensor signal circuit the for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 11	Go to Step 8
7	Inspect for poor connections at the harness connector of the ambient light sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 11	Go to Step 9
8	Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 11	Go to Step 10
9	Replace the ambient light sensor. Refer to Ambient Light Sensor Replacement . Did you complete the replacement?	-	Go to Step 11	-
10	IMPORTANT: Perform the setup procedure for the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?	-	Go to Step 11	-
11	Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC set again?	-	Go to Step 2	System OK