DTC P0451: Fuel Tank Pressure Sensor Circuit Range/Performance
- Remove fuel filler cap. Turn ignition on. Measure voltage (backprobe) between PCM 32-pin connector terminal No. 29 (Light Green wire) and PCM 31-pin connector terminal No. 18 (Green/Yellow wire). If about 2.5 volts are present, go to next step. If about 2.5 volts are not present, replace fuel tank pressure sensor.
- Turn ignition off. Open fuel vent assembly cover in front of EVAP control canister. Disconnect vacuum hose between EVAP 2-way valve and fuel tank pressure sensor at EVAP 2-way valve end. Connect vacuum pump to open end of hose.
- Turn ignition on. Measure voltage between 32-pin PCM connector terminal No. 29 (Light Green wire) and PCM 31-pin connector terminal No. 18 (Green/Yellow wire). Carefully pump vacuum one stroke at a time. Voltage should smoothly drop from about 2.5 volts down to about 1.5 volts. Stop applying vacuum when voltage drops to about 1.5 volts, or fuel tank pressure sensor may be damaged. If voltage drops to about 1.5 volts and holds, replace PCM. If voltage does not drop to about 1.5 volts and hold, replace fuel tank pressure sensor.