P0443: EVAP Purge Control Valve Circuit
P0443 means the engine computer found an electrical fault in the circuit of the EVAP purge valve, a small valve that lets fuel vapor from the charcoal canister into the engine. The check engine light comes on, but the car is generally safe to drive, and the most common cause is a corroded or loose connector at the valve.
You can keep driving
The data lists no limp mode for this code, and the fault affects only the vapor-recovery system. Expect the check engine light and possibly a fuel smell, and fix it soon because the car will not pass an emissions inspection while the light is on.
What it means
The evaporative emission (EVAP) system traps fuel vapor from the tank in a charcoal canister. The purge valve opens briefly so the engine can draw that vapor off and burn it. The engine computer switches the valve on and off in pulses and compares the voltage it reads back with what it commanded. P0443 sets when the two do not match, which points to a problem with the valve's wiring, its coil, its power supply, or the computer's driver for it. Some makes use the code only for an open circuit and report shorts under other codes (P0458 and P0459). Others cover both open and short in P0443. While the fault is present, purging stops, the canister is no longer cleaned out, and the computer suspends its EVAP leak and purge tests.
Likely causes
- Purge valve connector corroded, loose or offVery likely
A poor connection at the valve interrupts the circuit and looks to the computer like an open wire.
- Purge valve coil open or shortedPossible
The valve is an electrical coil, and if it fails internally the computer sees the wrong feedback voltage.
- Control wire broken or chafed, or supply missing (fuse, main relay)Possible
A damaged wire or a lost power feed stops the valve from being switched correctly.
- Driver in the engine moduleLess likely
The computer's internal switch for the valve can fail, though this is the least common cause.
What you may notice
- Check engine light on
- Possible fuel smell, since vapor is not being purged
- EVAP leak test does not run, so related readiness monitors stay incomplete
What to check, cheapest first
- 1Look at the purge valve connector for corrosion, bent pins, or a plug that is loose or has come off, then reseat it firmly. · you can do it
- 2Inspect the visible wiring to the purge valve for breaks, chafing, or rodent damage. · you can do it
- 3Check the fuses and the main relay that supply the purge valve circuit. · you can do it
- 4Clear the code and drive normally to see whether it returns. The code needs a drive cycle to be confirmed again. · you can do it
- 5Test the purge valve coil resistance and compare it with the specification for the vehicle. · mechanic
- 6Check the control wire, supply voltage and ground pulses at the connector, and if all are good, test the driver in the engine module. · mechanic
Related codes
Frequently asked questions
Can I drive with P0443?+
Yes, in most cases. The code affects the vapor-recovery system and the data lists no limp mode, but you should repair it soon.
Can a loose gas cap cause P0443?+
Not usually. P0443 is an electrical circuit fault at the purge valve. A loose cap is more associated with EVAP leak codes such as P0441 or P0449 type faults.
Will P0443 pass an emissions test?+
No. The check engine light is on and the EVAP monitors cannot complete, so the car is likely to fail until it is repaired and the monitors have run.
Can I fix it myself?+
Often yes. The repair is rated easy, with an estimated 0.3 to 1.5 hours, and a connector or the valve itself is a common fix.
Written with the help of AI from the public OBDex definition (CC0). Each make may use the code differently. Updated: 2026-11-10