P0453: OBD-II code P0453 flags a high-voltage signal from the fuel tank pressure sensor — the PCM sees an unrealistically high reading, usually a bad sensor or open ground.

Symptoms

• Check engine light is on; the vehicle typically drives normally with no drivability symptoms.
• EVAP self-test cannot complete because the PCM can't trust tank pressure data.
• The vehicle will fail emissions testing until the EVAP monitor completes and reports ready.

Common causes

• A failed fuel tank pressure sensor stuck at high voltage output.
• An open ground wire between the sensor and the PCM, pulling the signal to reference voltage.
• A shorted-to-voltage signal wire between the sensor and the PCM.

What to do?

Read live tank pressure in scan data. Check ground continuity from the sensor to the PCM. Backprobe the signal wire; disconnecting the sensor should change the reading. Replace sensor or repair wiring.