What does it mean?
P1431 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Fuel Level Sensor 2 Signal Range/Performance .
Symptoms
- MIL on and an inaccurate or jumping fuel gauge
- Gauge reads full or empty regardless of the actual level
- Range to empty display behaves erratically
- EVAP monitors may not run because fuel level data is not trusted
- Possible unexpected fuel starvation when one tank side does not transfer
Likely causes
- Worn resistive track on the second sender unit, common in vehicles with a saddle shaped tank
- Sticking float arm caught on tank internals or on a damaged baffle
- High resistance from corroded terminals at the sender flange connector
- Chafed or broken wire in the harness running along the tank
- Poor ground for the sender assembly
- Transfer pump or jet pump fault leaving one tank side full while the other empties
- Instrument cluster or PCM comparison fault when both senders disagree
How to fix it
- Compare both fuel level sensor values in live data and note whether they track each other while fuel is used
- Inspect the sender connector on the tank flange for corrosion, moisture and loose terminals
- Backprobe the sender signal wire and watch resistance or voltage change as the float is moved during removal
- Test the sender ground for excessive voltage drop
- Check the harness along the tank and under the rear seat for chafing and breaks
- Verify that the transfer or jet pump keeps both tank sides balanced
- Replace the faulty sender unit only after the wiring is proven, then refill and observe the gauge through a full tank cycle