P0443
DTC P0443
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC P0443
- Evaporative Emission (EVAP) Purge Solenoid Valve Control Circuit
Diagnostic Fault Information
Circuit/System Description
An ignition voltage is supplied directly to the evaporative emission (EVAP) purge solenoid valve. The engine control module (ECM) grounds the EVAP purge solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. The EVAP purge solenoid valve is pulse width modulated (PWM). A scan tool will display the amount of ON time as a percentage. If the ECM detects an incorrect voltage for the commanded state of the driver this DTC sets.
Conditions for Running the DTC
* The system voltage is between 11-32 V.
* DTC P0443 runs continuously when the above conditions are met.
Conditions for Setting the DTC
The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for a minimum of 0.25 s.
Action Taken When the DTC Sets
DTC P0443 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P0443 is a Type B DTC.
Reference Information
Schematic Reference
Engine Controls Schematics (LS3) [1][2]Electrical DiagramsEngine Controls Schematics (LS7) [1][2]Electrical DiagramsEngine Controls Schematics (LS9) [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views 5 Bow Lowered Switch (CM7)
Description and Operation
Evaporative Emission Control System Description Description and Operation
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON, engine OFF, command the EVAP purge solenoid to 50 % with a scan tool. You should hear the solenoid clicking when commanded to 50 %.
2. Engine Idling, command the EVAP purge solenoid from 0 to 50 % and back to 0 % with a scan tool while observing the following control circuit status parameters:
* EVAP Purge Solenoid Valve Control Circuit Low Voltage Test Status
* EVAP Purge Solenoid Valve Control Circuit Open Test Status
* EVAP Purge Solenoid Valve Control Circuit High Voltage Test Status
Each parameter should display OK or Not Run.
3. 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.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the Q12 Evaporative Emission Purge Solenoid Valve.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal A and ground.
• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is not open, test all components connected to the voltage supply circuit and replace as necessary.
3. Verify that a test lamp does not illuminate between the ignition circuit terminal A and the control circuit terminal B.
• If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.
4. Remove the test lamp, and install a 3 A fused jumper wire between the control circuit terminal B and the ignition circuit terminal A. Command the purge solenoid to 50 % with a scan tool. Verify the scan tool EVAP Purge Solenoid Valve Control Circuit High Voltage Test Status parameter is Malfunction.
• If not the specified value and, the circuit tests normal, replace the K20 Engine Control Module.
5. If all circuits test normal, replace the Q12 Evaporative Emission Purge Solenoid Valve.
Component Testing
1. Ignition OFF, disconnect the harness connector at the Q12 Evaporative Emission Purge Solenoid Valve.
2. Test for 18-28 ohms between the control terminal A and the ignition voltage terminal B.
• If not within the specified range, replace the Q12 Evaporative Emission Purge Solenoid Valve.
3. Test for infinite resistance between each terminal and the EVAP purge solenoid valve housing.
• If not the specified value, replace the Q12 Evaporative Emission Purge Solenoid Valve.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Evaporative Emission Canister Purge Solenoid Valve Replacement (LS9) Service and RepairEvaporative Emission Canister Purge Solenoid Valve Replacement (Without LS9) Service and Repair
* Control Module References Control Module References for ECM replacement, setup, and programming