EVAP Leak Detection Orifice High Flow
The P043F code indicates that the powertrain control module (PCM) has detected an abnormally high flow through the evaporative emission (EVAP) system leak detection reference orifice. This orifice is a calibrated restriction used during the EVAP system leak test to measure flow. High flow suggests a leak or malfunction in the EVAP system, such as a stuck-open purge valve, cracked hose, or faulty vent valve, causing the system to fail the leak detection test.
01. Most Common Causes
- Stuck open EVAP purge valve
- Cracked or disconnected EVAP hose
- Faulty EVAP vent valve stuck open
- Damaged EVAP canister
- Leaking fuel cap or missing cap
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Possible fuel odor
- Failed emissions test
- No noticeable drivability issues
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect EVAP hoses, connections, and fuel cap for damage or looseness.
Step 3: Perform a smoke test to locate leaks in the EVAP system.
Step 4: Test the purge valve and vent valve operation using a scan tool or manual activation.
Step 5: Check the EVAP canister for cracks or damage.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, it is generally safe to drive, but the Check Engine Light will remain on and the vehicle may fail an emissions test. It is recommended to repair promptly to avoid potential fuel vapor leaks.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and repair, depending on the cause. Replacing a purge valve or vent valve can cost $100-$200, while a smoke test is usually around $50-$100.