2010 Cadillac CTS Sedan AWD V6-3.6L Page 195
The HVAC control module detects the signal circuit is less than 5 counts or greater than 250 counts.
Action Taken When the DTC Sets
* The driver information center (DIC) will display SERVICE A/C SYSTEM.
* If the DTC is set the system will act as if no sunload condition exists.
Conditions for Clearing the DTC
* The DTC will become history if the HVAC control module no longer detects the condition that set the DTC.
* 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 Sunload Sensor parameter. The reading should be between 5 and 250 counts and change with
sunlight changes.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the sunload sensor.
2. Test for less than 10 ohms between the ground circuit terminal C and ground.
瀚慖f greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts between the ground circuit terminal C and the appropriate signal circuit terminal listed below:
* Left solar load sensor circuit terminal A.
* Right solar load sensor circuit terminal B.
瀚慖f less than the specified range, test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the
HVAC control module.
瀚慖f greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the HVAC control
module.
4. If all circuits test normal, test or replace the sunload sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Headlamp Automatic Control Ambient Light Sensor Replacement (See: Lighting and Horns/Headlamp/Headlamp Dimmer Sensor/Service
and Repair)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for HVAC control module replacement, setup, and
