DTC 040

CIRCUIT DESCRIPTION
The solar/twilight sensor is a photo-electric cell that provides two inputs to the heater and A/C control system. The input for the sunload is at terminal 3 of the heater and A/C control. This is used by the controller for temperature control compensation based on additional heat from the sun (sunload.) The input for the twilight sentinel is at terminal 2. The twilight sentinel input is then processed by the controller and sent to the Body Control Module (BCM).

CONDITIONS FOR SETTING THE DTC
The voltage on circuits P11 or P111 significantly rises above 400 mV for 200 ms.

ACTION TAKEN WHEN THE DTC SETS
^ Stores a DTC 40 in the heater and A/C control memory.
^ The system will default to a assumed value of no solar heat (darkness).
^ DTCs 10, 12, 14, 26, 39, 55, and 169 may also appear when DTC 40 sets.

CONDITIONS FOR CLEARING THE DTC
^ The conditions for the fault are no longer present.
^ Using a scan tool.
^ A history DTC will clear after 20 consecutive ignition cycles if the condition for the fault is no longer present.

DIAGNOSTIC AIDS
^ In the event that the multiple DTCs set, first follow the repair procedures in the diagnostic table for DTC 40. If some or all of the multiple DTCs reappear after repairing the cause of DTC 40, follow the repair procedures given for the appropriate DTC.
^ If condition not present, refer to Testing for Intermittent and Poor Connections in Diagrams.

TEST DESCRIPTION

Steps 1-9:

The number(s) below refer to the step number(s) on the diagnostic table.
3. This step tests the reference voltage from the heater and A/C control.