EVAP Fuel Vapor Temperature Sensor Circuit Intermittent
The P2028 code indicates an intermittent fault in the evaporative emissions (EVAP) fuel vapor temperature sensor circuit. This sensor monitors the temperature of fuel vapors in the EVAP system to help detect leaks and control purge flow. An intermittent circuit issue can be caused by loose or corroded wiring, a failing sensor, or poor electrical connections. The code sets when the PCM detects an unexpected voltage fluctuation or signal dropout from the sensor.
01. Most Common Causes
- Loose or corroded electrical connector at the fuel vapor temperature sensor
- Damaged wiring or short circuit in the sensor circuit
- Faulty fuel vapor temperature sensor
- Intermittent open or short in the sensor ground or signal wire
- Poor PCM connection or internal PCM fault (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated (may flash intermittently)
- Possible failed emissions test
- No noticeable drivability issues in most cases
- Intermittent EVAP system malfunction codes may appear
03. Step-by-Step Diagnosis
Step 1: Scan for all stored codes and freeze frame data to confirm P2028 and check for related codes.
Step 2: Visually inspect the fuel vapor temperature sensor connector and wiring for damage, corrosion, or loose pins.
Step 3: Using a multimeter, check sensor resistance at ambient temperature (typically 2-10 kΩ) and compare to manufacturer specs.
Step 4: Wiggle test the wiring harness while monitoring sensor signal voltage with a scan tool to identify intermittent breaks.
Step 5: If no issues found, clear codes and test drive to see if code returns; if intermittent, consider replacing the sensor.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, it is generally safe to drive, but the Check Engine Light may cause you to fail an emissions test. The issue is intermittent and does not affect engine performance or safety.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150, including parts (sensor $20-$60) and labor (0.5-1 hour). Diagnosis may add extra cost if the intermittent fault is hard to locate.