Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
P0443
1. Ignition ON, engine OFF, you should hear a clicking sound when the EVAP canister purge solenoid valve is commanded to 50 percent with a
scan tool. The clicking sound should stop when the EVAP canister purge solenoid valve is commanded to 0 percent. The rate at which the
valve cycles should increase when the commanded state is increased, and decrease when the commanded state is decreased.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the
conditions that you observed from the Freeze Frame/Failure Records data.
P0449
1. Ignition ON, engine OFF, command the EVAP vent solenoid Not Venting and Venting with a scan tool.
2. Listen for a click when the valve operates. Verify that both the ON, and the OFF states are commanded.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed
from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the EVAP canister purge or vent solenoid valve.
2. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal A and ground.
锟斤拷If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests
normal and the voltage supply circuit fuse is open, test or replace the EVAP canister purge solenoid.
3. Connect a test lamp between the voltage supply circuit terminal A and the control circuit terminal B.
4. Command the EVAP canister purge solenoid valve to 50 percent with a scan tool, or the EVAP canister vent solenoid valve Not Venting and
Venting. The test lamp should respond to the command.
锟斤拷If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
锟斤拷If 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 ECM.
5. If all circuits test normal, replace the appropriate solenoid valve.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Evaporative Emission Canister Purge Solenoid Valve Replacement (See: Powertrain Management/Emission Control Systems/Evaporative
Emissions System/Canister Purge Solenoid/Service and Repair)
* Evaporative Emission Canister Vent Solenoid Valve Replacement (1500 Series) (See: Powertrain Management/Emission Control
Systems/Evaporative Emissions System/Evaporative Emission Control Canister/Canister Vent Valve/Service and Repair/Evaporative
Emission Canister Vent Solenoid Valve Replacement (1500 Series))Evaporative Emission Canister Vent Solenoid Valve Replacement (2500
Series) (See: Powertrain Management/Emission Control Systems/Evaporative Emissions System/Evaporative Emission Control
Canister/Canister Vent Valve/Service and Repair/Evaporative Emission Canister Vent Solenoid Valve Replacement (2500 Series))
* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming
P0451
DTC P0451-P0454
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.
