What it means
The EVAP fuel-vapor temperature sensor signal jumps or drops out intermittently — usually a connector or chafed wire.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The EVAP fuel-vapor temperature sensor reports vapor temperature to the control module for evaporative-emissions monitoring. P2028 sets when the sensor signal intermittently cuts out or jumps, often as vibration or harness movement disrupts the circuit.
Common causes
Most likely first.
- Intermittent connector or chafed wire
- Connector with intermittent contact under vibration
- Harness routed against vibrating component
Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
How to diagnose it
- Review freeze-frame data and graph the EVAP vapor-temperature signal while gently moving the harness to try to reproduce the dropout.
- Inspect the sensor connector for loose terminals, moisture, corrosion, or damaged seals.
- Follow the harness route and look for chafing or contact with vibrating, hot, or moving components.
- Check connector terminal tension and circuit continuity while flexing the harness, following the manufacturer's procedure.
- If the circuit stays stable, monitor sensor response through temperature changes to determine whether the sensor itself is intermittent.
Common fixes
- Secure the connector and repair its seal if moisture has entered.
- Repair loose or corroded sensor terminals.
- Repair chafed wiring and secure the harness away from vibration or abrasion.
- Replace the EVAP vapor-temperature sensor if its output drops out with stable wiring.
Can I keep driving?
The code generally does not make the vehicle unsafe to drive, but EVAP monitoring may be unreliable and the vehicle may fail emissions testing. If fuel odor is present, avoid flames and investigate promptly.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.