Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P0451: Fuel Tank Pressure (Ftp) Sensor Circuit Range/Performance Problem
2004 Acura 3.5RLSECTION DTC P0451: Fuel Tank Pressure (Ftp) Sensor Circuit Range/Performance Problem
- Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DIAGNOSTIC TROUBLE CODES
under SELF-DIAGNOSTIC SYSTEM. Remove fuel filler cap. Turn ignition switch ON (II). Measure voltage between PCM 22-pin connector D terminals No. 15 (Green/Yellow wire) and No. 22 (Green/Black wire) or monitor FTP sensor voltage with scan tool. See Figure
-Figure
. If about 2.5 volts are present, go to next step. If about 2.5 volts are not present, check vacuum lines for restriction or blockage. Repair as necessary. If vacuum lines are okay, replace Fuel Tank Pressure (FTP) sensor.CAUTION: Stop applying vacuum when voltage drops to about 1.5 volts. Damage to fuel tank pressure sensor may occur.
- Disconnect vacuum hose between EVAP 2-way valve and FTP sensor at EVAP 2-way valve end. Connect vacuum pump to EVAP 2-way valve end of vacuum hose. See Fig 1 . Turn ignition switch ON (II). Measure voltage between PCM 22-pin harness connector terminals No. 15 (Green/Yellow wire) and No. 22 (Green/Black wire) or monitor FTP sensor voltage with scan tool, while applying vacuum on hose one stroke at a time. If voltage smoothly drops from 2.5 to about 1.5 volts and holds, problem is intermittent. Check for poor connections or loose hoses at FTP sensor and fuel tank. If voltage does not smoothly drop from 2.5 to about 1.5 volts and hold, replace FTP sensor.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.