P0443 EVAP purge valve circuit fault

EVAP purge solenoid circuit

Monitor

EVAP faults let fuel vapour escape but rarely change how the car drives, and the main risk is a failed emissions test, so it is safe to drive while you arrange a fix.

It gets more serious if:

  • Inspect soon: You keep smelling raw fuel around the car, not just right after filling up
  • Stop: You see liquid fuel dripping or pooling under the car, or near the filler, tank or canister

Source: how we rate severity

P0443 in short

P0443 means the computer sees an electrical fault in the EVAP purge valve circuit. Most often the valve coil has failed open or the connector or wiring is damaged. It rarely affects how the car drives and is generally safe to drive, unless you smell or see fuel.

The purge valve is an electric solenoid the computer switches on to draw fuel vapour from the canister into the engine. The computer watches the circuit and sets P0443 when it sees an open or short.

Because this is an electrical code, start with the connector and wiring, then measure the valve coil. Nissan notes that failed purge valves usually read as an open circuit.

P0441 is the flow code for the same valve. If both are stored, fix the circuit first.

Most likely causes

These are general causes for this code across vehicles. None is specific to one make or model.

  1. Purge valve coil open or shorted

    Common general cause
    Why it ranks here
    Nissan says failed purge valves usually measure open, which breaks the circuit.
    What would change this
    Rises if the coil reads open or far from the typical 10–20 ohm range.
    How to test the evap canister purge valve

  2. Corroded, loose or damaged connector at the purge valve

    Common general cause
    Why it ranks here
    Connector faults are the other common way to open the circuit, and they cost nothing to check.
    What would change this
    Rises if the connector is loose, corroded or has a broken lock.
    How to test the evap canister purge valve

  3. Broken wire or no command signal reaching the valve

    Possible — needs testing
    Why it ranks here
    If the valve and connector test good, the signal may not be reaching the valve. A test light shows this.
    What would change this
    Rises if a test light at the connector does not flash when the valve is commanded.
    How to test the evap canister purge valve

  4. Valve damaged by charcoal from the canister

    Possible — needs testing
    Why it ranks here
    A saturated canister can shed charcoal that damages purge valves.
    What would change this
    Rises if charcoal grains are found in the valve or hoses.
    How to test the evap charcoal canister

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. With the engine off and cool, check the purge valve connector and nearby wiring for corrosion, looseness or chafing.

    Use cautionTool: flashlight

    Warning:Let the engine cool first. Parts in the engine bay can be hot enough to burn, and fuel vapour is flammable, so keep sparks and flames away.

  2. Unplug the purge valve and measure its coil resistance.

    Use cautionTool: multimeter

    Warning:Let the engine cool first. Parts in the engine bay can be hot enough to burn, and fuel vapour is flammable, so keep sparks and flames away.

  3. Have a shop connect a test light (noid light) to the valve connector and command the purge valve with a scan tool.

    Best left to a shopTool: noid light, scan tool with output controls

    Warning:Engine bay work with the ignition on. Keep clear of the fan, which can start without warning.

Symptoms

  • Check engine light on, usually with no change in how the car drives
  • Fails an emissions or smog test because of the light or an incomplete EVAP monitor
  • Persistent raw fuel smell around the car Gets more serious: stop and have it checked.
  • Liquid fuel dripping under the car Gets more serious: stop and have it checked.

How to fix

  1. Check the purge valve connector is fully clicked in.

    Warning:Engine off and cool.

  2. After a repair, drive normally for several days so the monitor can re-run. Clearing codes or disconnecting the battery resets readiness, so do it shortly before an inspection only if you then complete a drive cycle.

Parts and cost context

  • EVAP canister purge valve:Usually in the engine bay, on a hose between the canister line and the intake. Labour varies, so get a quote.
  • EVAP charcoal canister:If charcoal has reached the purge valve, the canister may need replacing too, or the new valve can fail again.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Volkswagen

  • 2009–2017

    Supported by vehicle data

    VW bulletin 20 17 02 lists P0443 among the codes where the N80 purge valve may be involved on 2009–2017 gasoline models (except Routan). It says to smoke test and check vacuum before replacing the valve. The bulletin is on NHTSA, but whether it is still current is not verified, so it is labelled vehicle data rather than confirmed.

    Where it is:N80 purge valve, engine bay

  • 20 17 02Status unverified

    EVAP purge valve (N80) diagnosis

    2009–2017 · issued · NHTSA MC-10125657

    For 2009–2017 gasoline Volkswagens (except Routan), lists the EVAP codes that can involve the N80 purge valve and says to smoke test the system and check vacuum before replacing the valve.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • P0441EVAP purge flow incorrect

    Same system Common general cause

    P0441 is the flow check on the same purge valve. A circuit fault can stop the valve working and set both. Fix P0443 first.

  • P0496EVAP purge flow when purge should be off

    Shares causes Supported by vehicle data

    VW lists P0443 and P0496 among the codes where the same N80 purge valve may be at fault.

All EVAP (evaporative emissions) codes

P0443 questions

Is P0443 an electrical problem or a vapour leak?

It is electrical. The computer sees an open or short in the purge valve circuit. Check the connector and the valve coil before looking for leaks.

How do I know the purge valve is bad?

A valve with an open coil when measured is bad. If the coil reads normal, check that the command signal reaches the valve before replacing it.

Is it safe to keep driving?

Usually yes, as long as there is no strong fuel smell and no fuel dripping. Most makers advise getting it fixed when it is convenient. A strong fuel smell means get it checked soon, and dripping fuel means stop and do not drive.

Sources and review

  1. Frequently Asked Questions on On-Board Diagnostics (EPA 420-F-97-003) — US EPA ,
  2. On-Board Diagnostic II (OBD II) Systems Fact Sheet — California Air Resources Board ,
  3. EVAP: The Phantom Emissions Menace (Nissan TechNews, May 2018) — Nissan North America (hosted by AutomotiveTechInfo) ,
  4. OBD Test Reference (rev 8.6) — California Bureau of Automotive Repair ,
  5. What do you mean my car is not ready? — New York State DMV
  6. Recall acknowledgement 17V-088: BMW i3 REx fuel tank vent line may chafe — BMW of North America / NHTSA
  7. Part 573 Safety Recall Report 15V-621 (Mazda 8615J): liquid fuel can enter the EVAP canister — Mazda North American Operations / NHTSA
  8. Cal. Code Regs. Tit. 13, § 1968.2 — Malfunction and Diagnostic System Requirements (OBD II) — California Air Resources Board (via Cornell LII)
  9. VW 20 17 02: EVAP purge valve (N80) diagnosis — Volkswagen of America / NHTSA ,
Last reviewed
Written by
Saurabh K.
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