OBD-II trouble code
P0443: Evaporative Emission System Purge Control Valve Circuit
An electrical fault in the EVAP purge valve's control circuit — one of the most common emissions codes, and usually a cheap fix.
Quick facts
- System
- Powertrain
- Category
- EVAP System
- Severity
- Low severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $50 – $300
- DIY difficulty
- Intermediate DIY
What does P0443 mean?
The EVAP system stores fuel vapors from the tank in a charcoal canister and, when conditions are right, the engine computer opens the purge control valve (purge solenoid) to draw those vapors into the intake and burn them. P0443 sets when the computer detects an electrical problem in the purge valve's control circuit — an open, a short, or an implausible load when it drives the valve. It's about the wiring and solenoid, not about whether vapor actually flowed (flow problems set P0441).
The purge valve is a small, inexpensive solenoid that cycles thousands of times per drive, and it's one of the most commonly replaced emissions parts on modern cars. Failed windings, corroded connectors, and chafed wires between the PCM and valve cover the vast majority of cases.
Symptoms depend on how the valve failed: electrically dead usually means no symptoms beyond the light, while a valve stuck open can cause rough idle, hard starting after refueling, and lean codes — the intake pulls raw vapor when it shouldn't.
Common causes
- Failed purge valve solenoid (open or shorted winding)
- Corroded or loose connector at the purge valve
- Chafed, open, or shorted control wiring
- Blown fuse feeding the circuit (where used)
- PCM driver fault (rare)
Symptoms
- Check engine light on
- Often no drivability symptoms at all
- Rough idle or stumble if the valve is stuck open
- Hard starting right after refueling (stuck-open cases)
- Failed emissions test
Diagnostic steps
- 1.Scan for companion EVAP codes (P0440-P0446, P0455/P0456) to frame the problem.
- 2.Inspect the purge valve connector and wiring for corrosion, damage, or a loose fit.
- 3.Measure the purge solenoid's resistance against spec — open or near-zero readings condemn the valve.
- 4.Command the valve with a scan tool: it should click audibly and pass/block vacuum accordingly.
- 5.Back-probe for power and ground while commanded if the solenoid tests good.
- 6.Replace the valve or repair wiring; clear codes and confirm readiness monitors complete.
Repair cost
$50 – $300
Purge valves are among the cheapest emissions fixes: $20-$100 for the part, and on most vehicles it's a 15-30 minute job near the intake. Wiring repairs vary but are rarely expensive here.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with evap system repair preselected. Adjust labor rate and vehicle category to fit your situation.
Related repairs
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.