B2648

DTC B2648

CIRCUIT DESCRIPTION
The sunload sensor assembly is a light sensitive photocell. The HVAC control module determines the ambient light based on the voltage from the sunload sensor assembly. The HVAC control module controls the headlamp automatic on/off and delayed off functions.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC B2648 Ambient Light Sensor Circuit High

CONDITIONS FOR RUNNING THE DTC
- The enable flag is set to enable.
- DTC B1327 is not current.
- The HVAC control module is powered.

CONDITIONS FOR SETTING THE DTC
- The sunload sensor assembly voltage is greater than 4.8 volts.
- The above condition is present for greater than 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The HVAC control module sets the variable ambient light status to status set to DARK.
- The HVAC control module sets a DTC.

CONDITIONS FOR CLEARING THE DTC
The HVAC control module does not detect a voltage greater than the predetermined value during the diagnostic self test.

TEST DESCRIPTION

Steps 1-11:

Step 12:

The numbers below refer to the step numbers on the diagnostic table.
3. This step tests for the proper operation of the circuit in the high voltage range.
4. This step tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the sunload sensor assembly signal circuit is shorted to battery positive voltage.