Possible causes

– Fuel Tank Pressure Sensor
– Fuel Tank Pressure sensor harness is open or shorted
– Fuel Tank Pressure sensor circuit poor electrical connection
– Faulty Engine Control Module (ECM)

When is the code detected?

An improper voltage signal from the fuel tank pressure sensor is sent to Engine Control Module (ECM).

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P0451 MAZDA Description

The Fuel Tank Pressure (FTP) pressure sensor detects pressure in the purge line. The sensor output voltage to the Engine Control Module (ECM) increases as pressure increases.

MAZDA Technical Service Bulletins for P0451 code