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Home >> Acura >> 2001 >> 3.2CL Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0451: Fuel Tank Pressure Sensor (Ftps) Circuit Range/Performance

DTC P0451: Fuel Tank Pressure Sensor (Ftps) Circuit Range/Performance

  1. Remove fuel filler cap. Turn ignition on. Measure voltage (backprobe) between PCM 31-pin harness connector terminal No. 29 (Light Green wire) and PCM 32-pin harness connector No. 18 (Light Green/Yellow wire) on MDX or (Green/Yellow wire) on 3.2CL and 3.2TL. See WIRING DIAGRAMS article. Repair as necessary. If about 2.5 volts are present, go to next step. If about 2.5 volts are not present, replace fuel tank pressure sensor.
  2. Turn ignition off. Remove four bolts and canister cover on MDX. Open fuel vent assembly cover in front of EVAP control canister on 3.2CL and 3.2TL. See COMPONENT LOCATION in SYSTEM & COMPONENT TESTING article. 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.
    NOTE: Damage to fuel tank pressure sensor may occur if vacuum is applied after voltage drops to 1.5 volts.
  3. Turn ignition on. Measure voltage between PCM 31-pin harness connector terminal No. 18 (Light Green/Yellow wire) on MDX or (Green/Yellow wire) on 3.2CL and 3.2TL and PCM 32-pin harness connector terminal No. 29 (Light Green wire). Carefully pump vacuum one stroke at a time. Voltage should drop smoothly 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, substitute known-good PCM, then recheck. If symptom or indication goes away, replace original PCM. If voltage does not drop to about 1.5 volts and hold, replace fuel tank pressure sensor.
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