DTC P0451: Fuel Tank Pressure (Ftp) Sensor Range/Performance Problem
- Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DTCS in SELF-DIAGNOSTICS - INTRODUCTION article. Remove fuel filler cap. Turn ignition on. Using scan tool, check FTP sensor voltage. Or, using backprobe set, measure voltage between PCM 32-pin connector "A" terminals No. 29 (Light Green wire) and 31-pin connector "C" terminal No. 18 (Green/Black wire). See Figure and Figure . If about 2.5 volts does not exist, go to next step. If about 2.5 volts exists, replace fuel tank pressure sensor.
- Remove fuel tank. See FUEL TANK under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Remove fuel tank pressure sensor assembly from fuel tank. Connect fuel tank pressure sensor sub-harness connector to access panel side connector. Disconnect vacuum hose located between EVAP 2-way valve and fuel tank pressure sensor at EVAP 2-way valve side. Connect vacuum pump to hose. Turn ignition on. Slowly apply vacuum to hose one stroke at a time. Using scan tool, check FTP sensor voltage, or using backprobe set, measure voltage between PCM 32-pin connector "A" terminals No. 29 (Light Green wire) and 31-pin connector "C" terminal No. 18 (Green/Black wire). Voltage should drop smoothly from about 2.5 volts to about 1.5 volts. DO NOT apply vacuum after voltage drops to 1.5 volts or damage to fuel tank pressure sensor may occur. Go to next step.
- If voltage does not drop to about 1.5 volts and hold, replace fuel tank pressure sensor. If voltage drops to about 1.5 and holds, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.