P0452: OBD-II code P0452 flags a low-voltage signal from the fuel tank pressure sensor — the PCM sees an unrealistically low reading, usually a bad sensor or shorted signal.

Symptoms

• Check engine light is on; the vehicle typically drives normally.
• 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 low voltage output.
• A shorted-to-ground signal wire between the sensor and the PCM.
• Corroded pins in the sensor connector (often near the fuel tank where road spray reaches it).

What to do?

Read live tank pressure in scan data — should sit near zero at rest and rise/fall with tank pressure changes. Disconnect and check reading (should jump to open-circuit value). Replace sensor or repair signal wiring as needed.