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Fuel gauge reads wrong: what it could be
If the fuel gauge sticks, jumps up and down or does not match what you fill up, the fuel level sender in the tank or its connection is usually at fault. The risk is running out of fuel without warning.
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Reviewed by Daniel Morales, founder of Reprorace SL, on
Is it serious? Can I keep driving?
Usually not urgent, but do not ignore it. You can drive, but keep track of the fuel yourself: note the miles since the last fill-up and refuel earlier than usual. On a diesel, running dry can mean the fuel system has to be bled.
A careful, general answer: only someone who inspects the car can say whether it is safe to drive. When in doubt, stop somewhere safe and call for assistance.
Most likely causes
- Fuel level sender: the resistive track wears and the reading jumps.
- Stuck or punctured float: the gauge stays put.
- Tank connector or wiring: readings that come and go.
- Instrument cluster: if other gauges fail as well.
Listed from more to less common in general; on your car they may be different. A fault-code reading and a check at the garage confirm which one it is.
To understand it better: What is live data and what is it for? Can I diagnose my car myself?
Car system: Fuel and air
What you can check yourself
Fill the tank and note the miles so you can work out the range yourself.
Notice whether it fails with the tank full, half full or nearly empty.
Check whether the trip computer shows a consistent range.
Safe checks only: with the engine off and cold whenever you look under the hood, without taking anything apart and without touching hot or moving parts.
Related fault codes
- P0460Fuel level sensor A, circuit: malfunction
- P0461Fuel level sensor A, circuit: range/performance
- P0462Fuel level sensor A, circuit: signal low
- P0463Fuel level sensor A, circuit: signal high
- P0464Fuel level sensor A, circuit: intermittent
Generic codes that often come with this symptom. Seeing one does not confirm the cause: it is where the diagnosis starts.
How the ECO-LITE helps diagnose it
Plugged into the OBD socket, the ECO-LITE reads the fault codes of the control units that answer, with the freeze-frame data captured when the fault happened, and shows live data on your phone or computer. With your permission, your garage can see them remotely before you bring the car in.
What to look at here: the fuel level reported by the control unit (if it matches the cluster, the fault is in the sender) and fuel level sensor codes.
Frequently asked questions
Why does it drop suddenly near the end?
It is common when the sender is worn in that range or because of the shape of the tank.
Can this turn on the check engine light?
On some cars, yes, with codes P0460 to P0464, because the control unit uses the level for its emissions tests.
Is it expensive to fix?
It depends on the car: the sender usually sits with the pump inside the tank.
Keep reading
- Fuel and air: how it works and what fails
- Instrument cluster goes dead or gauges fail: what to do
- Car uses more fuel than normal: causes and what to check
- Smell of gasoline or diesel in the car: what to do
- Car symptoms: what they mean and what to do
- Check engine light on: what to do
- How to read and clear your car's fault codes
- OBD fault codes: what each one means