M/T Model

DTC P0451: Fuel Tank Pressure Sensor Circuit Range/Performance Problem - M/T model

Special Tool Required
Vacuum Pump/Gauge, 0 - 30 in.Hg A973X-041-XXXXX

1. Remove the fuel fill cap.
2. Turn the ignition switch ON (II).




3. Monitor the FTP sensor voltage with the Honda PGM Tester, or measure voltage between ECM connector terminals A28 and E28.

Is there approx. 2.5 V?

YES - Go to step 4.

NO - Replace the fuel tank pressure sensor.

4. Turn the ignition switch OFF.




5. Open the fuel vent assembly cover (A) in front of the EVAP canister.
6. Disconnect the hose between the EVAP two-way valve and the fuel tank pressure sensor at the EVAP two-way valve end.




7. Connect a vacuum pump to the open end of the hose.
8. Turn the ignition switch ON (II).
9. Monitor FTP sensor voltage with the Honda PCM Tester, or measure voltage between ECM connector terminals A28 and E28, and carefully squeeze the vacuum pump one stroke at a time.
10. The voltage should smoothly drop from about 2.5 V to 1.5 V. STOP applying vacuum when the voltage drops to about 1.5 V or damage to the fuel tank pressure sensor may occur.

Does the voltage drop to approx. 1.5 V and hold?

YES - Substitute a known-good ECM and recheck. If the symptom/indication goes away, replace the original ECM.

NO - Replace the fuel tank pressure sensor.