EVAP Fuel Vapor Temperature Sensor Circuit High Voltage
The P2027 code indicates that the Engine Control Module (ECM) has detected a voltage signal from the evaporative emission (EVAP) fuel vapor temperature sensor that is higher than the expected range. This sensor monitors the temperature of fuel vapors in the EVAP system to help control purge flow. High voltage typically points to a short circuit to power, a faulty sensor, or a wiring issue. The EVAP system prevents fuel vapors from escaping into the atmosphere, so this fault can affect emissions and may trigger the check engine light.
01. Most Common Causes
- Faulty EVAP fuel vapor temperature sensor
- Short circuit to battery voltage in sensor wiring
- Corroded or damaged sensor connector
- Open circuit in sensor ground or signal wire
- ECM internal fault (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Possible failed emissions test
- Rough idle or hesitation (in some cases)
- Decreased fuel economy (minor)
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm code P2027 and check for related EVAP codes.
Step 2: Visually inspect the EVAP temperature sensor connector and wiring for damage, corrosion, or shorts.
Step 3: Disconnect the sensor and measure voltage at the harness connector (key on, engine off). Expected: 5V reference, 0V signal. If signal wire shows battery voltage, repair short.
Step 4: Test sensor resistance with a multimeter. Compare to manufacturer specs (typically 2-10 kΩ at room temperature). Replace if out of range.
Step 5: If wiring and sensor are good, suspect ECM fault; perform ECM diagnostic or reprogramming.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, it is generally safe to drive short distances, but the check engine light will be on and the vehicle may fail an emissions test. The EVAP system is not critical for engine operation, but a short circuit could cause other issues. It's best to diagnose and repair promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor. The sensor itself is inexpensive (around $20-$50), and labor is about 0.5-1 hour. If wiring repair is needed, costs may be higher.