DTC P0451: Fuel Tank Pressure Sensor Circuit Range/Performance Problem

WARNING: This page is about a different car, the 2003 Acura RSX. However, it is still accessible from the selected car via links, so may be relevant.

Perform ECM/PCM reset procedure. See ECM/PCM RESET PROCEDURE/CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. Remove fuel filler cap. Turn ignition switch on. Using scan tool, monitor Fuel Tank Pressure (FTP) sensor voltage or measure voltage between White ECM/PCM 31-pin "E" harness connector terminals No. 4 (Pink wire) and 14 (Light Green wire). 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 sensor.

CAUTION: Stop applying vacuum when voltage drops to about 1.5 volts. Damage to fuel tank pressure sensor may occur.

Disconnect hose to FTP sensor from EVAP 2-way valve end. Connect vacuum pump to open end of disconnected hose. Turn ignition switch on. Using scan tool, monitor FTP sensor voltage or measure voltage between White ECM/PCM 31-pin "E" harness connector terminals No. 4 (Pink wire) and 14 (Light Green wire). See Figure . Using vacuum pump, apply vacuum slowly. Voltage should smoothly drop from about 2.5 volts to about 1.5 volts. If voltage drops from about 2.5 volts down to about 1.5 volts, update ECM/PCM or substitute with known-good ECM/PCM. If symptom or indication goes away, replace original ECM/PCM. If FTP sensor voltage does not drop as specified, replace FTP sensor.