P2405 — Evaporative Emission System Leak Detection Pump Sense Circuit Low

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 P2405 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 for supply voltage at the evaporative emission system leak detection pump sense connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
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 P2405 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P2405 (parts and labor, USD, independent shop rates): Replace the purge or vent valve: $120–$350; Replace the charcoal canister: $250–$700; Replace the fuel cap: $20–$60. Overall, fixing P2405 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 P2405?

The most common causes are: loose, damaged or wrong fuel cap, saturated or damaged charcoal canister, faulty purge valve (canister purge solenoid).

Will P2405 clear itself?

Sometimes P2405 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

What does OBD2 code P2405 mean?

Evaporative Emission System Leak Detection Pump Sense Circuit Low (P2405): a powertrain (engine/transmission) fault affecting the evaporative emission (EVAP) system. The car is usually drivable while you plan the repair. Most often caused by loose, damaged or wrong fuel cap, saturated or damaged charcoal canister, faulty purge valve (canister purge solenoid).

How do I diagnose P2405 myself?

Start with a scan: confirm P2405, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the evaporative emission system leak detection pump sense, and verify the suspect component against live data before buying parts.

Is it safe to drive with P2405?

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 P2405 mean?

Behind P2405 is a specific failure in the evaporative emission (EVAP) system: evaporative emission system leak detection pump sense circuit low. The onboard computer stores it in the powertrain (engine/transmission) group after verifying the fault over repeated checks.

“Circuit low” means the voltage on the evaporative emission system leak detection pump sense circuit stays below the expected minimum — close to ground. The usual physical reasons are a short to ground, a chafed wire touching metal, a missing supply voltage, or a failed component dragging the signal down.

To set P2405, the control module compares live readings of the evaporative emission (EVAP) system against calibrated limits, usually over several drive cycles. Alongside the code it stores a freeze frame — a snapshot of rpm, load, coolant temperature and vehicle speed at the moment of failure. Reading that snapshot first saves diagnostic time.

Common symptoms of P2405

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

What causes P2405?

signal wire shorted to ground (chafed insulation)
failed evaporative emission system leak detection pump sense pulling the signal low
missing supply voltage to the evaporative emission system leak detection pump sense
saturated or damaged charcoal canister
cracked EVAP hoses or lines
faulty purge valve (canister purge solenoid)
loose, damaged or wrong fuel cap

How to diagnose P2405

Connect an OBD2 scanner, confirm P2405 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 for supply voltage at the evaporative emission system leak detection pump sense connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
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 P2405 does not return.

How to fix P2405

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

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

How much does it cost to fix P2405?

Repair cost depends on which component actually failed. Typical scenarios for P2405 (parts and labor, USD, independent shop rates):

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

Overall, fixing P2405 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.