What does it mean?
P1451 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: EVAP System Fuel Level Sensor Failure and Pressure Sensor Performance Problem .
Symptoms
- MIL on with the EVAP monitor stuck incomplete
- Fuel gauge inaccurate, jumping or frozen at one value
- Range to empty display unreliable
- Fuel vapour smell if a genuine leak also goes undetected
- No obvious loss of engine performance
Likely causes
- Worn resistive track in the fuel level sender giving a jumpy or fixed reading
- Corroded connector at the tank flange affecting both the sender and pressure sensor circuits
- Fuel tank pressure sensor drifted out of calibration or reading a fixed value
- Blocked, kinked or disconnected reference hose to the pressure sensor
- Shared 5 volt reference or ground fault affecting several EVAP sensors at once
- Damaged wiring along the underbody EVAP harness
- Contaminated fuel or debris in the tank interfering with float movement
How to fix it
- Compare fuel level and tank pressure values in live data, noting whether either is stuck or implausible
- Verify the 5 volt reference and sensor ground at both connectors, since a shared fault explains two failures at once
- Inspect the tank flange connector for corrosion, moisture and terminal pushback
- Check the pressure sensor reference hose for kinks, blockage and disconnection
- Watch the pressure value while gently applying and releasing vacuum with a hand pump
- Measure the fuel level sender resistance through its full float travel when the tank unit is accessible
- Replace the faulty sender or pressure sensor after the wiring and reference circuits are proven, then run an EVAP monitor drive cycle