P043E
EVAP System Leak Detection Reference Orifice Low Flow
EVAP (emissions)
Generic OBD-II
Medium
What it means
P043E is set when the evaporative-emissions leak-detection system measures less airflow than expected through its calibrated reference orifice during a self-test. That orifice provides the baseline the system compares against to check for fuel-vapor leaks, so low flow usually points to a blocked orifice or a weak leak-detection pump rather than anything that affects driving.
Medium
Can I keep driving? Yes — this is an emissions self-test fault, not a running problem; the car drives normally, but the EVAP monitor won't pass until it's fixed.
Common symptoms
What you'll notice
- Check-engine light on
- No noticeable change in how the car drives
- May fail an emissions/readiness test
- Occasionally a faint fuel smell if paired with a real EVAP leak
Common causes
Most likely first
- Blocked or contaminated reference orifice in the leak-detection assemblyLikely
- Faulty leak-detection pump or module that draws air through the orificeCommon
- Restricted or pinched EVAP hoses feeding the reference checkCommon
- Wiring or connector fault at the leak-detection pump/moduleLess often
- ECM control or calibration issue (least common)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm no companion large-leak codes are stored first.
- Locate the EVAP leak-detection pump/module and inspect the reference orifice for dirt, debris, or blockage.
- Check the pump's electrical connector and wiring for corrosion or damage.
- Test the leak-detection pump operation per the service procedure; replace the pump/module if the orifice or motor is faulty.
- Clear the code and run the EVAP monitor drive cycle to confirm the repair.
FAQ
Quick answers
Is it safe to drive with P043E?+
Yes. It's an evaporative-emissions self-test fault and does not affect how the car runs or starts. Get it fixed so the EVAP monitor can pass, especially before an emissions test.
Can I just clear P043E?+
You can, but it returns after the next EVAP self-test if the reference orifice or leak-detection pump is still faulty. Fix the cause first.
Related codes
Often seen with P043E
Read & clear P043E yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX