P0443 — EVAP purge valve — electrical control circuit

P0443 concerns the electrical control circuit for the EVAP purge valve, which meters stored fuel vapours from the charcoal canister into the intake. It differs from P0441 (incorrect purge flow) and EVAP leak codes P0442/P0455. The code alone does not prove a mechanically stuck valve or a leaking fuel tank.

Affected system: Powertrain

Symptoms

• Check-engine lamp; some vehicles show no driveability change.
• Rough idle or starting trouble if purge flow is also disturbed, but not inevitable from an electrical DTC.
• Fuel smell is not inherent to P0443 and requires a separate leak/safety inspection.

Possible causes

• Open/shorted purge-solenoid winding on designs that use a solenoid.
• Damaged feed/control wire, terminal, shared fuse or, only after external checks, ECU driver fault.
• Blocked hoses or canister may cause additional EVAP flow faults, but do not alone explain the electrical P0443 circuit detection.

What to check

• 1. Capture the full DTC, freeze-frame and any related EVAP flow or circuit faults. P0441 flow diagnosis must not be conflated with an active P0443 electrical fault.
• 2. Locate the purge valve and OEM feed/driver architecture. Purge-to-intake is not the canister vent valve implicated by P0449.
• 3. Inspect purge connector, heat-exposed wiring and appropriate shared fuses. Repair proved broken or corroded terminals before substituting the valve.
• 4. Check supply and the commanded driver only under OEM enable conditions. No feed points to an external supply fault; no switching when purge is not commanded does not prove a bad driver.
• 5. If supported, command purge with a bidirectional scan tool and observe the electrical drive. Valid drive without physical actuation warrants coil/valve checks; missing drive at the connector warrants wiring diagnosis.
• 6. Test the disconnected coil and harness against the correct OEM pinout and limits. Confirmed open or short determines which circuit/part needs repair; do not impose a generic resistance figure.
• 7. With the electrical circuit proved sound, separately evaluate mechanical flow or a valve held open only where symptoms/additional DTCs warrant it. A cracked hose is a different failure mode.
• 8. Verify command response under the correct engine conditions, check idle and confirm P0443 does not return. Stop testing and inspect for leaks if strong fuel odour appears.

Also written as: P0443-00, P044300, PO443 (some scan tools add the fault-type byte, e.g. -00).