P043F code meaning
EVAP System Leak Detection Reference Orifice High Flow
Powertrain system Generic code P04xx codes Check engine light
What P043F means
The evaporative emission (EVAP) system stores fuel vapour from the tank in a charcoal canister; a purge valve lets the engine draw it off, and a vent valve opens the canister to fresh air. Systems with a leak detection pump (Bosch DM-TL at VW, Audi, BMW and Maserati, Denso's canister pump module at Toyota/Lexus) first measure a reference value with the pump working only through a built-in 0.5 mm (0.020 in) orifice; it is the yardstick for the small-leak test that CARB requires. P043F means the reference measurement shows too much flow – the reference vacuum or pressure does not reach the expected value, because the reference path or changeover valve leaks, the pump is weak, or air enters through leaking valves in the test path. The leak test can then not be judged, since a weak yardstick would hide leaks. GM and Ford do not use the code.
P043F at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P043F
- Check engine light on
- EVAP leak test does not run, readiness not set
- Usually no change in driving
Common causes of P043F
- Most likelyLeak detection pump faulty (weak pump, leaking changeover valve, liquid damage)
- PossiblePurge valve does not seal
- PossiblePump supply or connector (contact resistance, corrosion)
- Less likelyLeaking hose between pump module and canister
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EVAP leak detection pumpReference orificeCharcoal canisterEngine control module
What each part of P043F means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 3F | The exact fault in that area. |
What to do next
- Note P043F and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P043F
What does P043F mean?
P043F means "EVAP System Leak Detection Reference Orifice High Flow". The evaporative emission (EVAP) system stores fuel vapour from the tank in a charcoal canister; a purge valve lets the engine draw it off, and a vent valve opens the canister to fresh air. It is a generic code, so it means the same on every make.
Is it safe to drive with P043F?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P043F fail an emissions test?
Yes, it can. P043F is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P043F to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P043F clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.