2010 Cadillac CTS Sedan AWD V6-3.6L Page 191
- Passenger Compartment Temp Sensor Circuit Short to Ground or Open
Diagnostic Fault Information
Circuit/System Description
The HVAC control module monitors the air temperature sensors with a low reference circuit and 5-volt signal circuit. The HVAC control module
monitors the voltage drop across the sensor. When the ambient air temperatures are cold, the resistance of the sensor is high and the voltage signals
are high. When the ambient air temperatures are hot, the resistance of the sensors is low and the voltage signals are low.
Conditions for Running the DTC
Ignition ON.
Conditions for Setting the DTC
* The HVAC control module detects the sensor signal circuit is less than -35掳C (-39掳F).
* The HVAC control module detects the sensor signal circuit is greater than 85掳C (185掳F).
Action Taken When the DTC Sets
The HVAC control module uses a default air temperature value for further automatic control calculations. The default values are not displayed on
the scan tool. The DIC will display the SERVICE A/C SYSTEM message.
Conditions for Clearing the DTC
* The DTC will become history if the HVAC control module no longer detects a failure.
* The history DTC will clear after 50 fault-free ignition cycles.
Reference Information
Schematic Reference
HVAC Schematics (See: Heating and Air Conditioning/Diagrams/Electrical Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Automatic HVAC Description and Operation (See: Heating and Air Conditioning/Description and Operation/HVAC - Automatic)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
Ignition ON, observe the appropriate scan tool Air Temp Sensor parameter. The reading should be between -35掳C (-39掳F) and 85掳C (185掳F) and
change with air temperature changes.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate air temperature sensor.
2. Ignition OFF, test for less than 10 ohms between the following low reference circuit terminal and ground.
* Inside air temperature sensor terminal 2.
* Ambient temperature sensor terminal B.
