P2403 — Evaporative Emission System Leak Detection Pump Sense Circuit/Open

P2403 — Evaporative Emission System Leak Detection Pump Sense Circuit/Open. A fault in the evaporative emission (EVAP) system. The car is usually drivable while you plan the repair. Typical causes: saturated or damaged charcoal canister, cracked EVAP hoses or lines, loose, damaged or wrong fuel cap.

powertrain (engine/transmission)

Is it safe to drive?

Short-term driving is OK Safe to drive. EVAP faults affect emissions, not drivability — you can keep using the car while planning the repair. Fuel vapour smell is a reason to fix it sooner: vapours are flammable and harmful.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm P2403 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the evaporative emission (EVAP) system for damage, corrosion, chafing or poor contact.
Subsystem check Check the fuel cap first — it is the most common cause; inspect the seal and tighten until it clicks.
Subsystem check Run an EVAP leak test (smoke test) to locate small leaks in hoses, canister and valves.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2403 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P2403 (parts and labor, USD, independent shop rates): Replace the fuel cap: $20–$60; Replace the charcoal canister: $250–$700; Replace the purge or vent valve: $120–$350. Overall, fixing P2403 usually costs between $20 and $700. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

What is the most common cause of P2403?

The most common causes are: saturated or damaged charcoal canister, cracked EVAP hoses or lines, loose, damaged or wrong fuel cap.

What are the symptoms of P2403?

Drivers most often notice: difficulty refueling (nozzle clicks off), Check Engine Light on, no noticeable driving symptoms in most cases, slightly worse fuel economy.

Is it safe to drive with P2403?

Safe to drive. EVAP faults affect emissions, not drivability — you can keep using the car while planning the repair. Fuel vapour smell is a reason to fix it sooner: vapours are flammable and harmful.

What does OBD2 code P2403 mean?

How do I diagnose P2403 myself?

Start with a scan: confirm P2403, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the evaporative emission (EVAP) system, and verify the suspect component against live data before buying parts.

What does P2403 mean?

Seeing P2403 on your scanner? The control unit has caught the evaporative emission (EVAP) system operating outside its calibrated window. The formal description is “Evaporative Emission System Leak Detection Pump Sense Circuit/Open”, and the code is grouped under powertrain (engine/transmission) faults.

This code does not appear from a single bad reading: the module must see the fault condition repeat under defined operating conditions before it turns on the warning light. The freeze frame captured with P2403 — engine load, rpm, temperature, speed — tells you exactly when the problem occurs, so reproduce those conditions when testing.

What causes P2403?

faulty vent valve or leak detection pump
cracked EVAP hoses or lines
faulty purge valve (canister purge solenoid)
small leak in the fuel tank or filler neck
loose, damaged or wrong fuel cap

Common symptoms of P2403

difficulty refueling (nozzle clicks off)
Check Engine Light on
no noticeable driving symptoms in most cases
slightly worse fuel economy
fuel smell near the car, especially after refueling

How to diagnose P2403

Connect an OBD2 scanner, confirm P2403 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Visually inspect the wiring harness and connectors related to the evaporative emission (EVAP) system for damage, corrosion, chafing or poor contact.
Check the fuel cap first — it is the most common cause; inspect the seal and tighten until it clicks.
Run an EVAP leak test (smoke test) to locate small leaks in hoses, canister and valves.
Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2403 does not return.

How to fix P2403

Start with the cheapest and most common causes before replacing expensive parts:

Replace the fuel cap — $20–$60
Replace the charcoal canister — $250–$700
Replace the purge or vent valve — $120–$350

How much does it cost to fix P2403?

Repair cost depends on which component actually failed. Typical scenarios for P2403 (parts and labor, USD, independent shop rates):

Replace the fuel cap: $20–$60
Replace the charcoal canister: $250–$700
Replace the purge or vent valve: $120–$350

Overall, fixing P2403 usually costs between $20 and $700. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.