P2403
EVAP System Leak Detection Pump Sense Circuit/Open
EVAP / emissions
Generic OBD-II
Low
What it means
P2403 refers to the evaporative emissions (EVAP) leak-detection pump's sense circuit reading open. That pump pressurizes the EVAP system to check for fuel-vapor leaks; when its sense (feedback) circuit is open, the PCM can't run the leak test. This is an emissions-monitor circuit fault — the engine runs and drives normally, but the vehicle won't pass an emissions test until it's repaired.
Low
Can I keep driving? Yes — the car drives normally. This is an EVAP monitor circuit fault with no effect on power; it mainly prevents the leak test and will fail emissions until fixed.
Common symptoms
What you'll notice
- Check-engine light on — usually the only symptom
- May fail an emissions or smog test
- No noticeable change in how the vehicle runs
- A faint fuel odor only if an actual EVAP leak is also present
Common causes
Most likely first
- Open or damaged wiring/connector at the EVAP leak-detection pumpLikely
- Faulty leak-detection pumpCommon
- Corroded pump connector terminalsCommon
- Blown fuse feeding the leak-detection pump circuitLess often
- Faulty PCM (rare)Less often
How to diagnose & fix
Work through it in order
- Inspect the leak-detection pump connector and wiring for opens, corrosion, or damage.
- Check the fuse and power feed to the pump circuit.
- Test the pump and its sense circuit against the manufacturer's spec.
- Replace the leak-detection pump if its sense circuit is internally open.
- Clear the code and confirm the EVAP monitor completes.
FAQ
Quick answers
Is it safe to drive with P2403?+
Yes. It's an emissions-system circuit fault with no effect on power or safety, but it should be repaired so the car passes emissions.
Can I just clear P2403?+
It returns when the EVAP monitor next runs unless the open circuit or pump is repaired.
Related codes
Often seen with P2403
Read & clear P2403 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