2010 Cadillac Truck SRX FWD V6-3.0L Page 247

2010 Cadillac Truck SRX FWD V6-3.0L Page 247

* HVAC Component Replacement Reference (See: Heating and Air Conditioning/Service and Repair/Removal and Replacement)

* Control Module References (See: Testing and Inspection/Programming and Relearning)

B0183

DTC B0163, B0183, or B1405

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

overview of the diagnostic approach.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure

Instructions) provides an overview of each diagnostic category.

DTC Descriptor

DTC B0163 02

- Passenger Compartment Temperature Sensor Circuit Short to Ground

DTC B0163 05

- Passenger Compartment Temperature Sensor Circuit High Voltage/Open

DTC B0183 02

- Solar Load Sensor Circuit Short to Ground

DTC B0183 05

- Solar Load Sensor Circuit High Voltage/Open

DTC B1405 02

- Control Module Voltage Reference Output 2 Circuit Short to Ground

DTC B1405 05

- Control Module Voltage Reference Output 2 Circuit High Voltage/Open

Circuit/System Description

The ambient light/sunload sensor includes the sunload sensor and passenger compartment temperature sensor.

This sensor assembly provides information about:

* Sun heat intensity

* Elevation

* Azimuth

* Passenger compartment temperature

The sunload sensor is connected to ground and to a 12 V clocked power supply through the HVAC control module. This clocked power supply is to

power the sensor electronics and to work as a clock generator to the sunload sensor micro controller. The sensor uses a pulse signal for data

identification and transferring the sun intensity measurement. At each positive transition from the clocked supply input, the sunload sensor micro

controller will shift channels enabling new intensity measurement on the signal output to the HVAC control module. The signal voltage varies

between 0-4 V.

The passenger compartment temperature sensor is a negative temperature co-efficient thermistor. A signal and low reference circuit enables the

sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0-5 V.

Bright or high intensity light causes the vehicles interior temperature to increase. The HVAC system compensates for the increased temperature by

diverting additional cool air into the vehicle.

Conditions for Running the DTC

* Ignition ON.

* The HVAC control module is ON.

Conditions for Setting the DTC