2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1374
4. Command the EVAP purge solenoid to 50 percent and then to 0 percent with a scan tool. The test lamp should illuminate or flash and then go
OFF.
瀚慖f the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
瀚慖f the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace
the K20 ECM.
5. Test for 2.6-4.6 V between the control circuit terminal 2 and the ECM housing.
瀚慖f the voltage is not within the specified range, replace the K20 ECM.
6. If all circuits test normal, test or replace the Q12 EVAP purge solenoid.
Component Testing
1. Ignition OFF, disconnect the harness connector at the EVAP purge solenoid. Test for 15-20 ohm between the terminals of the EVAP purge
solenoid.
瀚慖f not within the specified range, replace the Q12 EVAP purge solenoid.
2. Measure the resistance between each terminal of the EVAP purge solenoid and the EVAP purge solenoid housing. The DMM should display
O.L.
瀚慖f less than the specified value, replace the Q12 EVAP purge solenoid.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Evaporative Emission Canister Purge Solenoid Valve Replacement (LF1) (See: Powertrain Management/Emission Control
Systems/Evaporative Emissions System/Canister Purge Solenoid/Service and Repair)Evaporative Emission Canister Purge Solenoid Valve
Replacement (LAU) (See: Powertrain Management/Emission Control Systems/Evaporative Emissions System/Canister Purge
Solenoid/Service and Repair)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming
P0459
DTC P0443, P0458, or P0459 (LAU)
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 Descriptors
DTC P0443
- Evaporative Emission (EVAP) Purge Solenoid Control Circuit
DTC P0458
- Evaporative Emission (EVAP) Purge Solenoid Control Circuit Low Voltage
DTC P0459
- Evaporative Emission (EVAP) Purge Solenoid Control Circuit High Voltage
Diagnostic Fault Information
Circuit/System Description
