P0451

Fuel tank pressure sensor malfunction

Detection Condition

• While the ECU performs the evaporative leak monitor function or when the purge solenoid valve is intentionally closed, the difference in fuel tank pressure is too small or too large

Diagnostic Support Notes

• This is a continuous monitor (CCM)
• The check engine indicator illuminates if the ECU detects the above malfunction condition during the first drive cycle
• PENDING CODE is available
• FREEZE FRAM DATA is available
• DTC is stored in ECU memory

Possible Causes

• Fuel tank pressure sensor malfunction
• Purge solenoid valve malfunction
• Canister drain/cut valve (CDCV) malfunction
• Poor connection of canister drain/cut valve (CDCV), fuel tank pressure sensor and/or ECU connection
• Short circuit in wiring and canister drain/cut valve
• Charcoal canister restriction

[P0451 - From 2002 Mazda Millenia factory service manual]