2010 Cadillac Truck SRX FWD V6-3.0L Page 99

2010 Cadillac Truck SRX FWD V6-3.0L Page 99

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 Descriptors

DTC B018A 02

- Windshield Temperature Sensor Circuit Short to Ground

DTC B018A 05

- Windshield Temperature Sensor Circuit High Voltage/Open

DTC B048C 02

- Humidity Sensor Humidity Circuit Short to Ground

DTC B048C 05

- Humidity Sensor Humidity Circuit High Voltage/Open

DTC B048F 02

- Humidity Sensor Temperature Circuit Short to Ground

DTC B048F 05

- Humidity Sensor Temperature Circuit High Voltage/Open

DTC B1395 03

- Control Module Voltage Reference Output Circuit Low Voltage

DTC B1395 07

- Control Module Voltage Reference Output Circuit High Voltage

Circuit/System Description

The windshield temperature and inside moisture sensor includes the relative humidity sensor, windshield temperature sensor and humidity sensing

element temperature sensor.

This sensor assembly provides information about:

* Relative humidity level at windshield inside

* Temperature of the windshield inside

* Temperature of the humidity sensor element

The relative humidity sensor measures the relative humidity of the compartment side of the windshield. It also detects the temperature of the

windshield surface on the compartment side. Both values are used as control inputs for the HVAC control module application to calculate the fog

risk on windshield compartment side and ability to reduce fuel consumption by decreasing A/C compressor power to a minimum without causing

any fog. The sensor will also enable partial recirculation mode in order to improve heat-up performance of the passenger compartment under cold

ambient temperature conditions without the risk of mist build-up on the windshield. The humidity sensor element temperature sensor supplies the

temperature of the humidity sensor element. It is only needed if the thermal contact between the humidity sensing element and the inside windshield

surface is not sufficient.

Conditions for Running the DTC

* Ignition ON.

* The HVAC control module is ON.

Conditions for Setting the DTC

B018A 02, B048C 02, B048C 02 or B1395 03

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V for more than 50 ms.

B018A 05, B048C 05, B048C 05 or B1395 07

The HVAC control module detects the sensor signal out of range. The signal voltage is greater than 4.9 V for more than 50 ms.

Action Taken When the DTC Sets

* The system will use the last valid values as default.

* If no value is read at the time of fault, the HVAC control module uses 60% for humidity.