DTC P0451: Fuel Tank Pressure (Ftp) Sensor Range/Performance Problem
- Clear Diagnostic Trouble Codes. See CLEARING DIAGNOSTIC TROUBLE CODES
. Remove fuel filler cap. Turn ignition on. Using scan tool, check FTP sensor voltage or backprobe between PCM connector "D" (16-pin connector) terminals No. 11 (Green/Black wire) and No. 15 (White/Blue wire). See Figure
. If about 2.5 volts do not exist, go to next step. If about 2.5 volts exist, replace fuel tank pressure sensor.
- Disconnect vacuum hose between EVAP 2-way valve and FTP sensor at EVAP 2-way valve and connect vacuum pump/gauge to hose. See Fig 1
. Turn ignition on. Monitor FTP sensor voltage with scan tool, or backprobe between PCM connector "D" (16-pin connector) terminals No. 11 (Green/Black wire) and No. 15 (White/Blue wire) while carefully applying a small amount of vacuum to hose, one stroke at a time. 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 FTP sensor may occur. Go to next step.
- If voltage does not drop to about 1.5 volts and hold, replace FTP sensor. If voltage drops to about 1.5 volts and holds, substitute a known-good PCM and retest. See SUBSTITUTING POWERTRAIN CONTROL MODULE
. If symptom/indication goes away, replace original PCM. Perform final procedure. See FINAL PROCEDURE
.
Courtesy of AMERICAN HONDA MOTOR CO., INC.