Powertrain, generic (extended)

P2403 EVAP System Leak Detection Pump Sense Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

The sense circuit carries the feedback by which the engine computer knows what the leak detection pump is actually doing. P2403 is logged when that feedback is missing as if the line were open. The January 2014 Golf book from VW sets it once the sense signal stays at a low voltage for more than 0.5 s. Jaguar's bulletin JTB00436 for the XJ (X351, 2010 onwards) lists P2403 among the DMTL codes caused by road spray freezing or collecting in the pump filter, and Ford's code list for the 2014 Boss 302S carries the same title. Compared with P2400 the pump may run normally; only its feedback is lost. P2405/P2406 are the low/high siblings, P2404 the plausibility check. The tank leak test cannot be evaluated; drivability is not affected.

Likely causes

Broken feedback wire or backed-out terminal at the pump connector
Water or ice trapped in the pump or its filter (Jaguar XJ)
Failed feedback element inside the pump

Symptoms

  • Check engine light
  • EVAP monitor not completed
  • More often after winter driving or car washes

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–500
Time0.5–2 h

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

Parts involved

evap leak detection pumpevap pump wiring

Related codes

P2404P2405P2406P2400

References: static.nhtsa.gov, static.nhtsa.gov, performanceparts.ford.com, law.cornell.edu.