DTC P0443, P0458, or P0459 (LAU or LBW)
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DTC P0443, P0458, or P0459 (LAU or LBW)
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DTC P0443
Evaporative Emission (EVAP) Purge Solenoid Valve Control Circuit
DTC P0458
Evaporative Emission (EVAP) Purge Solenoid Valve Control Circuit Low Voltage
DTC P0459
Evaporative Emission (EVAP) Purge Solenoid Valve Control Circuit High Voltage
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Diagnostic Fault Information
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Circuit
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Short to Ground
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Open/High Resistance
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Short to Voltage
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Signal Performance
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Ignition Voltage
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P0443, P0458
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P0443
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EVAP Canister Purge Valve Control Circuit
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P0458
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P0443
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P0459
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Circuit/System Description
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The evaporative emission (EVAP) canister purge valve is used to purge fuel vapor from the EVAP canister to the intake manifold. The EVAP canister purge valve is pulse width modulated (PWM). Ignition voltage is supplied directly to the EVAP canister purge valve. The engine control module (ECM) controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.
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Conditions for Running the DTC
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The engine speed is more than 80 RPM.
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The ignition voltage is between 10-18 V.
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The ECM has commanded the EVAP canister purge valve ON and OFF at least once during the ignition cycle.
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The DTCs run continuously when the above conditions are met.
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Conditions for Setting the DTC
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P0443
The ECM detects the EVAP canister purge solenoid control circuit is open. The condition exists for 4 s or a cumulative of 30 s.
P0458
The ECM detects the EVAP canister purge solenoid control circuit is shorted to ground. The condition exists for 4 s or a cumulative of 30 s.
P0459
The ECM detects the EVAP canister purge solenoid control circuit is shorted to voltage. The condition exists for 4 s or a cumulative of 30 s.
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Action Taken When the DTC Sets
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DTC P0443, P0458 and P0459 are Type B DTCs.
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Conditions for Clearing the DTC
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DTC P0443, P0458 and P0459 are Type B DTCs.
If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the scan tool EVAP Purge Solenoid Circuit Test Status parameters for the component. A circuit test status parameter changes from OK or Not Run to Fault if there is a condition with the circuit or a connection.
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Evaporative Emission Control System Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
for scan tool information
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Circuit/System Verification
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1.
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Ignition ON, command the EVAP purge solenoid valve to 50 percent with a scan tool. You should hear an audible click.
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2.
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Engine operating, observe the scan tool EVAP Purge Solenoid Circuit Test Status parameters. Verify the parameters display OK or Not Run.
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3.
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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.
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1.
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Ignition OFF, disconnect the harness connector at the Q12 EVAP purge solenoid Valve.
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2.
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Ignition ON, verify a test lamp illuminates between the ignition voltage circuit terminal 2 and ground.
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3.
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If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition voltage circuit fuse is open, test all components connected to the ignition voltage circuit and replace as necessary.
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4.
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Connect a test lamp between the control circuit terminal 1 and the ignition voltage circuit terminal 2.
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5.
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Note
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The control circuit for the EVAP purge solenoid is pulled-up to voltage within the ECM, 2.6-4.6 volts on the control circuit is normal.
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Command the EVAP purge solenoid valve to 50 percent and then to 0 percent with a scan tool. The test lamp should illuminate or flash and then go OFF.
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6.
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If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
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7.
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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 K20 ECM.
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8.
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Test for 2.6-4.6 V between the control circuit terminal 1 and the K20 ECM.
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9.
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If the voltage is not within the specified range, replace the K20 ECM.
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10.
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If all circuits test normal, test or replace the Q12 EVAP purge solenoid.
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1.
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Ignition OFF, disconnect the harness connector at the Q12 EVAP purge solenoid valve. Test for 15-20 Ω between the terminals of the Q12 EVAP purge solenoid valve.
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2.
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If not within the specified range, replace the Q12 EVAP purge solenoid valve.
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3.
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Measure the resistance between each terminal of the Q12 EVAP purge solenoid valve and the EVAP purge solenoid valve housing. The DMM should display OL.
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4.
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If less than the specified value, replace the Q12 EVAP purge solenoid.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
