P2027: EVAP Fuel Vapor Temperature Sensor Circuit High Voltage

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.

Low severity. Can I keep driving?Yes, you can normally keep driving. If there is a strong smell of gasoline, find the leak before continuing and do not smoke nearby.

Symptoms

Check engine lamp on
Vapor temperature shown far below ambient

Most likely causes

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

What to check, in order

Start with the simplest. You can tick off each step.

Start with the fuel cap: tighten it fully and check its seal
Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
Inspect the hoses and connections around the tank and the charcoal canister
Use the scanner to test the purge and vent solenoid valves
Run a smoke test to find small leaks

Good to know

Repair difficulty: medium
It affects emissions.

What each character of P2027 means

P: Powertrain: engine and transmission
2: Generic code: same on every make
0: Subsystem depends on the code range
27: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2027?

Yes, you can normally keep driving. If there is a strong smell of gasoline, find the leak before continuing and do not smoke nearby.

What causes code P2027?

The most common causes are: open circuit – broken wire or unplugged connector; signal wire shorted to reference or battery voltage; temperature sensor open internally.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.