P0450

Fuel tank pressure sensor circuit malfunction

Detection Condition

• ECU monitors the input voltage from the fuel tank pressure sensor when the engine coolant temperature is below 80 degrees C.  If the input falls below 0.2V or above 4.8V after the engine is started, the ECU determines that the fuel tank pressure sensor circuit has malfunctioned.

Diagnostic Support Notes

• This is a continuous monitor (CCM)
• Check engine indicator illuminates if the ECU detects the above malfunction condition in two consecutive drive cycles
• PENDING CODE is available
• FREEZE FRAME DATA is available
• DTC is stored in ECU memory

Possible Causes

• Fuel tank pressure sensor malfunction
• Connector or terminal malfunction
• Short to ground in wiring between fuel tank pressure sensor terminal A and ECU
• Open circuit in wiring between fuel tank pressure sensor terminal C and ECU
• Open circuit in wiring between fuel tank pressure sensor terminal A and ECU
• Open circuit in wiring between fuel tank pressure sensor terminal B and ECU
• Fuel tank pressure sensor signal circuit is shorted to reference voltage (Vref) supply circuit
• ECU malfunction

[P0450 - From 2002 Mazda Millenia factory service manual]