EVAP System Leak Detection Orifice Low Flow (P043E)
The P043E code indicates that the powertrain control module (PCM) has detected insufficient airflow through the evaporative emission (EVAP) system's leak detection reference orifice during the monitor test. This orifice is a calibrated restriction used to verify the system's ability to detect leaks. Low flow suggests a blockage or restriction in the EVAP system, such as a clogged vent valve, pinched hose, or a faulty purge valve. This can prevent the system from properly pressurizing and detecting leaks, potentially leading to increased evaporative emissions.
01. Most Common Causes
- Clogged or restricted EVAP vent valve
- Pinched or blocked EVAP vapor hose
- Faulty purge valve stuck closed
- Blocked or damaged leak detection pump assembly
- Debris or foreign material in the EVAP system
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Possible fuel odor near the vehicle
- Failed emissions test
- No noticeable drivability issues in most cases
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm the code and check for related EVAP codes.
Step 2: Visually inspect EVAP hoses and connections for damage, kinks, or blockages.
Step 3: Test the EVAP vent valve operation using a scan tool or manual vacuum pump.
Step 4: Check the purge valve for proper operation and ensure it is not stuck closed.
Step 5: Perform a smoke test to locate any restrictions or blockages in the EVAP system.
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 vehicle may fail an emissions test and the Check Engine Light will remain on. It is recommended to repair the issue to prevent potential fuel vapor leaks.
How much does it cost to fix?▼
The cost typically ranges from $100 to $300, depending on the root cause. Replacing a vent valve or purge valve can cost $150-$250, while clearing a blockage may be less expensive.