2010 Cadillac Truck Escalade RWD V8-6.2L Page 2521
module will not allow the A/C compressor to operate.
Conditions for Running the DTC
* Engine is running.
* Any of the conditions for setting the DTC are met for 15 seconds.
Conditions for Setting the DTC
* The HVAC control module detects that the A/C pressure is less than 2.03 psi (14 kPa) sets DTC P2518 12.
* The HVAC control module detects that the A/C pressure is more than 101.5 psi (700 kPa) sets DTC P2518 11.
Action Taken When the DTC Sets
The A/C compressor is disabled.
Conditions for Clearing the DTC
* The history DTC will clear after 40 consecutive ignition cycles have occurred without a malfunction.
* The DTC will become history if the HVAC control module no longer detects a failure.
Diagnostic Aids
A malfunction within the refrigerant system causing high pressure can cause this DTC to set.
Reference Information
Schematic Reference
HVAC Schematics (See: Heating and Air Conditioning/Diagrams/Electrical Diagrams/HVAC - Automatic)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
* Air Delivery Description and Operation (See: Heating and Air Conditioning/Description and Operation/HVAC - Automatic/Air Delivery
Description and Operation)
* Air Temperature Description and Operation (See: Heating and Air Conditioning/Description and Operation/HVAC - Automatic/Air
Temperature Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/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 scan tool Low Pressure Switch parameter. The parameter should read closed.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the A/C refrigerant pressure sensor.
2. Ignition OFF, test for less than 10 ohms between the low reference circuit terminal 1 and ground.
瀚慖f greater than the specified range, test the low reference circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 2 and ground.
瀚慖f less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance.
瀚慖f greater than the specified range, test the 5-volt reference circuit for a short to voltage.
