P0452: Evaporative Emission System Pressure Sensor/Switch Low Input

What does P0452 mean?

The EVAP pressure-sensor signal is below its calibrated electrical limit. This may be a sensor or wiring fault; interpreting the voltage as actual tank pressure requires the engine-specific sensor specification.

Generic OBD-II definition: Evaporative Emission System Pressure Sensor/Switch Low Input. Confirm applicability in your vehicle service information.

Common causes

• Signal shorted to ground
• Failed tank-pressure sensor
• Poor sensor connection or reference supply

Symptoms

• Steady check engine light
• Often no noticeable driving change
• EVAP readiness may not complete

Diagnostic focus

A loose cap can matter to EVAP testing, but tightening it is not proof that a low-input circuit fault is fixed. Confirm that the sensor voltage returns to the correct range.

Can I keep driving with P0452?

Severity: Low With normal running and no fuel smell or leakage, arrange an emissions-system check. If you smell strong fuel vapor or see a leak, stop safely and have it inspected; keep ignition sources away.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

• Check tank-pressure data with the system in the specified vented state
• Test sensor supply, ground, and low signal
• Inspect vapor lines if the electrical checks are normal

Sources & review

• OBD-Codes.com: P0452
• TroubleCodes.net: generic code definitions

Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.