2010 Cadillac Truck SRX FWD V6-3.0L Page 1498
Fuel Tank Pressure Sensor
1. Ignition OFF, disconnect the harness connector at the fuel tank pressure sensor.
2. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal and ground.
瀚慖f greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the fuel
tank pressure sensor.
Repair Instructions
* Evaporative Emission Canister Vent Solenoid Valve Replacement (NT7, NU5) (See: Powertrain Management/Emission Control
Systems/Evaporative Emissions System/Evaporative Emission Control Canister/Canister Vent Valve/Service and Repair)
* Evaporative Emission Canister Replacement (NT7, NU5) (See: Powertrain Management/Emission Control Systems/Evaporative Emissions
System/Evaporative Emission Control Canister/Service and Repair)
* Fuel Tank Pressure Sensor Replacement (See: Powertrain Management/Computers and Control Systems/Fuel Tank Pressure Sensor/Service
and Repair)
* Control Module References (See: Testing and Inspection/Programming and Relearning)
Repair Verification
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
With the engine running, the evaporative emission canister vent solenoid valve open and the evaporative emission canister purge solenoid valve
commanded to 100 percent, the fuel tank vacuum should not increase to more than -15 mmHg (-8 inches H2O).
P0449
DTC P0443 or P0449 (LF1)
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 Valve Control Circuit
DTC P0449
- Evaporative Emission (EVAP) Vent Solenoid Valve Control Circuit
Diagnostic Fault Information
Circuit/System Description
An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid valve. The engine control module (ECM)
grounds the evaporative emission canister purge solenoid valve control circuit through an internal switch called a driver. The ECM monitors the
status of the driver. The evaporative emission canister purge solenoid valve is pulse width modulated (PWM). A scan tool will display the amount
of ON time as a percentage.
Battery voltage is supplied to the EVAP canister vent solenoid valve. The ECM grounds the EVAP canister vent solenoid valve control circuit
through an internal switch called a driver. The ECM monitors the status of the driver. A scan tool will display the commanded state of the
evaporative emission canister vent solenoid valve as ON or OFF.
Conditions for Running the DTC
