The P1443 code indicates an EVAP Purge Flow Monitoring Fault — meaning the purge valve, purge flow sensor, or EVAP plumbing is not flowing vapor the way the ECM expects. Depending on the vehicle brand, this code may also appear as: EVAP Purge Valve Performance, Purge Flow Incorrect, or EVAP Purge Sensor Low/No Response.
This fault is commonly associated with stuck purge valves, cracked EVAP hoses, or restricted charcoal canisters. It is related to issues found in P1440 EVAP System Fault and P1441 Purge Flow Sensor Fault.
What Does P1443 Actually Mean?
The ECM monitors how much fuel vapor should be pulled from the charcoal canister during purge. When purge flow is too low, too high, or doesn’t match expected sensor feedback, the ECM sets P1443.
Long-tail search variants naturally embedded: how to fix P1443 EVAP purge flow fault, P1443 purge valve stuck open symptoms, P1443 incorrect purge flow diagnosis.
Common Symptoms of P1443
- Check Engine Light illuminated
- Strong fuel smell near the vehicle
- Hard starting after refueling
- Rough idle when purge is commanded
- Failed emissions test due to incomplete EVAP monitor
Most Likely Causes
- Faulty purge valve (stuck open/closed)
- Blocked or saturated charcoal canister
- Cracked, disconnected, or collapsing EVAP hoses
- Purge flow or pressure sensor failure
- Electrical issues in the purge control circuit
- Vacuum leaks affecting expected purge flow
How to Diagnose P1443 – Step-by-Step (Technician Method)
You’ll need a scan tool capable of active tests and EVAP data monitoring.
- Scan for codes + freeze frame Check whether P1443 appears alone or with siblings like P1440 / P0441 / P1441.
-
Inspect purge valve & hoses
Look for cracked hoses, loose clamps, or damaged connectors. -
Command the purge valve (with a tool like CR Ultra P)
Observe engine idle change — no reaction often means stuck valve or restricted flow. -
Monitor EVAP flow / pressure readings
If the sensor shows no change during purge commands → likely sensor or port blockage. -
Check for canister restriction
A fuel-soaked canister can’t pass vapor, causing P1443. -
Perform smoke test
Check for fine cracks or leaks in EVAP plumbing.
Best Professional Tool for Diagnosing P1443 — iCarsoft CR Ultra P
The iCarsoft CR Ultra P is ideal because it can:
- Run purge valve active tests
- Graph EVAP flow and pressure sensor values in real time
- Perform system monitor resets
- Support 200+ brands including Ford, GM, Toyota, Honda, BMW, Mercedes, VW, and more
- Handle 1996–2025+ models with DoIP, CAN FD & full-system diagnostics
Get iCarsoft CR Ultra P – Diagnose P1443 Accurately
Typical Repair Costs
| Repair | Typical Cost |
|---|---|
| Replace purge valve | $120–$280 |
| Replace/repair EVAP hoses | $80–$240 |
| Replace charcoal canister | $250–$550 |
| Purge flow sensor replacement | $150–$350 |
FAQ – P1443 Troubleshooting
Is P1443 serious?
Not typically dangerous, but it will cause emissions test failure and persistent fuel odor in some cases.
Will a stuck purge valve trigger P1443?
Yes — a stuck-open purge valve is one of the most common causes of incorrect purge flow.
Can a bad charcoal canister cause P1443?
Absolutely. A saturated or blocked canister prevents vapor movement and often sets P1443.
Best scan tool for EVAP purge flow testing?
iCarsoft CR Ultra P supports purge valve actuation and EVAP sensor monitoring across most vehicles.
External references: OBD-Codes | EPA.gov emissions standards
