Powertrain, generic (extended)

P2404 EVAP System Leak Detection Pump Sense Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2404 is a plausibility code: the pump feedback is electrically present but does not behave as the leak test expects. VW's 2014 Golf data book sets it when the sense signal stays high for more than 30.4 s (12 s on another engine) over 30 checks, or when high signal time during pumping adds up to more than 10 s. Subaru has issued a series of bulletins since 2023 (09-102-23 to 09-131-25, many models) because condensation in the ELCM can trigger P2404 falsely; the fix is a leak test, a 35-minute ELCM pump active test and new ECM software. For the 2011-2014 Touareg 3.6, VW linked P2404 to coolant in the pump's vacuum line, and Land Rover lists P2404 with failure types 29 and 2F. P2403 covers a dead feedback, P2407 an unstable one.

Likely causes

Condensation inside the leak check module (Subaru ELCM, software update available)
Worn or sticking pump that no longer reaches its expected state in time
Coolant or debris in the pump's vacuum or vent line

Symptoms

  • Check engine light, often returning after clearing
  • EVAP readiness not set

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–600
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

evap leak detection pumpevap pump wiring

Related codes

P2403P2407P24B9P0442

References: static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.