Powertrain, generic (extended)

P2027 EVAP Fuel Vapor Temperature Sensor Circuit High Voltage

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2027 is the high-voltage counterpart of P2026: the signal sits near the reference, which an NTC sensor would only produce at a temperature far below anything plausible. In practice the sensor circuit is open – a broken wire, an unplugged connector, a corroded pin – or the signal line is shorted to a voltage source. Ford's 2014 code list names P2027 among MIL-relevant faults, but no manufacturer publicly describes its threshold or timing. On Audi vehicles the sensor sits inside leak detection unit J909 at the canister, so an open there affects the whole unit. CARB treats sensors used by the EVAP monitor as input components that must be checked for out-of-range values. Until the circuit is fixed, the leak test cannot run and EVAP readiness stays open.

Likely causes

Open circuit – broken wire or unplugged connector
Signal wire shorted to reference or battery voltage
Temperature sensor open internally

Symptoms

  • Check engine lamp on
  • Vapor temperature shown far below ambient

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–400
Time0.3–2 h

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

Parts involved

evap fuel vapor temp sensorevap harness

Related codes

P2024P2025P2026P2028

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