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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2006 🢒 DTS 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 DTC P0443

DTC Descriptor

DTC P0443: Evaporative Emission (EVAP) Purge Solenoid Control Circuit

Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Ignition 1 Voltage - Purge Supply

P0443

P0443

P0443

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EVAP Purge Solenoid Control

P0443

P0443

P0443

P0443

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Circuit/System Description

An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid valve. The EVAP canister purge solenoid valve is pulse width modulated (PWM). The scan tool displays the amount of ON time as a percentage. The control module monitors the status of the driver. The control module controls the EVAP canister purge solenoid valve ON time by grounding the control circuit via an internal switch called a driver.

Conditions for Running the DTC
    • The ignition is ON.
    • The system voltage is between 9-18 volts.
    • DTC P0443 runs continuously when the above conditions are met.

Conditions for Setting the DTC

The control module detects that the commanded state of the driver and the actual state of the control circuit do not match for a minimum of 12 seconds.

Action Taken When the DTC Sets
    • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC
    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Engine Control Module Connector End Views
    •  Engine Controls Connector End Views
    •  Scan Tool Data Definitions

Electrical Information Reference

    •  Circuit Testing
    •  Troubleshooting with a Test Lamp
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Output Controls

Circuit/System Verification

With the ignition ON, and the 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.

Circuit/System Testing
  1. Turn OFF the ignition.
  2. Disconnect the EVAP canister purge solenoid valve.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the ignition 1 voltage circuit of the EVAP canister purge solenoid valve with a test lamp that is connected to a good ground.
    5. ⇒If the test lamp does not illuminate, test the circuit for an open or for a short to ground.
  5. Connect a test lamp between the control circuit of the EVAP canister purge solenoid valve and the ignition 1 voltage circuit of the EVAP canister purge solenoid valve.
    6. ⇒If the test lamp illuminates, test the control circuit of the EVAP canister purge solenoid valve for a short to ground.
  6. Command the EVAP canister purge solenoid valve to 50 percent with a scan tool.
    7. ⇒If the test lamp does not flash or illuminate with the command, test the control circuit of the EVAP canister purge solenoid valve for an open or for a short to voltage.
    ⇒If the circuits and the control module test normal, replace the EVAP canister purge solenoid valve.

Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Evaporative Emission Canister Purge Solenoid Valve Replacement
    •  Control Module References for engine control module (ECM) replacement, setup, and programming