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P2405 Generic (SAE) Basic entry

Evaporative Emission System Leak Detection Pump Sense Circuit Low

Updated 2026-10-02 · Fuel, air & emissions (P2)

Severity
Low
Typical repair cost
10 – 400 EUR
System
Powertrain

What it means

P2405 is stored when the self-test of the Evaporative Emission System Leak Detection Pump Sense cannot hold the applied vacuum or pressure, which indicates a leak in a hose, seal, valve or the fuel cap.

This entry is compiled automatically from the standard definition and typical diagnostic practice for this type of fault. A detailed, reviewed article is in preparation.

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Symptoms

  • Check engine light on
  • Rough or unstable idle
  • Hesitation or poor acceleration
  • Increased fuel consumption
  • Possible limp mode with reduced power

Common causes

  1. Loose, worn or incorrect fuel cap
  2. Cracked or disconnected hose
  3. Purge or vent valve not sealing
  4. Damaged canister or filler neck
  5. Leaking seal on the fuel tank sender or pump flange

How to diagnose

  1. Check the fuel cap: tighten until it clicks or replace the seal
  2. Inspect all hoses and connections of the Evaporative Emission System Leak Detection Pump Sense for cracks and loose fittings
  3. Smoke test the system through the service port and look for escaping smoke
  4. Command the vent and purge valves with a scan tool and verify they seal
  5. Clear the code and allow several drive cycles for the monitor to complete

Frequently asked questions

Can I keep driving with P2405?

Yes. The fault does not affect safety or driveability, but it will keep the warning light on and may fail an inspection.

Will clearing P2405 fix it?

No. Clearing only erases the stored code; it returns as soon as the monitor runs again unless the cause is repaired.

Related codes

P2404P2406P2407

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