P043E: EVAP System Leak Detection Reference Orifice Low Flow
During the EVAP leak-detection self-test, the calibration airflow through the reference orifice is below the expected rate. The orifice may be partially blocked.
What P043E means
P043E is a generic OBD-II powertrain code in the emissions group. In plain English: the fuel-vapor (EVAP) system failed its leak self-test, so fuel vapor may be escaping from the tank, cap, hoses or valves.
- Check engine light
- Usually on
- Emissions-related
- Yes — can fail inspection
- Limp mode possible
- Not typical
- Drive cycle to clear
- Not required
Get it fixed
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Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
Common causes
- 01Reference orifice partially blockedMost likely
Can I drive with P043E?
Generally yes.
This fault is unlikely to affect how the car drives, but it will usually fail an emissions inspection. Fix it when convenient.
Why we rate it low
- Turns on the check engine light
- Emissions-related: will usually fail an OBD inspection
- EVAP leaks rarely affect how the car drives
Severity is our rule-based rating from the code’s flags in OBDex and the system it affects, not an inspection of your car. If the check engine light is flashing, or you notice overheating, low oil pressure, or brake or steering problems, stop driving and get help.
How to diagnose P043E
- 1
Confirm the code and save freeze-frame data
Read the codes with an OBD-II scan tool and note every code, not just P043E. Save the freeze-frame data (speed, load, temperature when the fault set) before clearing anything; it tells you when the fault happens.
- 2
Fix other faults first
If other codes are stored, start with power-supply, sensor-circuit and communication codes. They can cause this code as a side effect.
- 3
Test the circuit
Inspect the wiring and connector at the evap leak detection pump and evap canister for damage, corrosion or chafing. With a multimeter, check supply voltage, ground and signal against the specifications in the service manual for your vehicle.
- 4
Test the likely causes in order
Start with the most likely cause and work down: Reference orifice partially blocked. Test before replacing parts.
- 5
Check for recalls and service bulletins
Look up recalls for your exact vehicle with its VIN, and ask a dealer about technical service bulletins (TSBs). Manufacturers sometimes issue software updates or extended warranties for known faults.
- 6
Clear the code and verify the repair
After the repair, clear the code and drive the car under the conditions in the freeze-frame data to confirm it does not return.
P043E repair cost estimate
Estimate, not a quote. Labor times are typical ranges for this code from OBDex, and $125/hr is an assumed rate. Shop rates and labor times vary by vehicle and region. Diagnosis time may be billed separately.
- DIY difficulty
- Moderate
- Good DIY job?
- Usually a shop job
Needs a scan tool and some experience with testing.
Parts and systems involved
- EVAP leak detection pump
- EVAP canister
P043E FAQ
What does P043E mean?
P043E means “EVAP System Leak Detection Reference Orifice Low Flow”. During the EVAP leak-detection self-test, the calibration airflow through the reference orifice is below the expected rate. The orifice may be partially blocked.
Is P043E serious? Can I keep driving?
We rate P043E as low severity. Generally yes. This fault is unlikely to affect how the car drives, but it will usually fail an emissions inspection. Fix it when convenient.
What causes P043E?
The most common causes, from most to least likely: Reference orifice partially blocked. Test before replacing parts, because several causes can set the same code.
How much does it cost to fix P043E?
Typical labor is about $90–$375 at an assumed $125/hour shop rate, plus parts. That is an estimate, not a quote: labor times and rates vary by vehicle and region, and diagnosis may be billed separately.
Can I fix P043E myself?
DIY difficulty is moderate. Most owners leave this to a shop because it needs involved testing or specialist tools. Always confirm the cause before buying parts.
Will P043E clear itself?
If the fault was intermittent, the warning may go off once the computer stops seeing it, but the code stays in memory. Fix the cause; clearing the code alone doesn’t repair anything.