The fuel meter assembly is the gauge or display, usually located in the instrument cluster, that displays the amount of fuel present in the vehicle’s fuel tank. The fuel meter assembly usually displays the fuel level as a needle on a gauge that is separated into sections, or as a digital, numerical readout. The gauge serves the simple purpose of letting the driver know the vehicle’s current fuel level so that the driver can accurately gauge when fuel needs to be added. When the fuel meter assembly fails, engine performance will often be unaffected, however the overall drivability of the vehicle will be affected as the driver will have to deal with not having an accurate fuel level indicator. As the fuel meter assembly is usually controlled by the fuel sending unit, many of the symptoms of a bad fuel meter assembly are similar to those of a bad sending unit. A bad fuel meter assembly will usually produce a few specific symptoms that can alert the driver of a potential issue.
1. Erratic behavior from the fuel gauge
One of the first symptoms of a problem with the fuel meter assembly is erratic behavior from the gauge. If the fuel sending unit that is located in the gas tank fails or has any issues it can cause the needle or display to behave erratically. The position of the needle or the digit on the gauge may change suddenly, or drop in and out unpredictably, and function apparently fine at other times. An inaccurate fuel reading can make it difficult to know when the vehicle will require refueling.
2. Fuel gauge stuck on empty
Another symptom of a potential issue with the fuel gauge is stuck on empty. Once more, if the fuel sending unit has an issue or fails, it can cut off or give a bad signal to the gauge, which may cause it to stay on empty. In some vehicles the low fuel light will still work independently of the fuel gauge or readout, however the vehicle will be left without any sort of indicator for the fuel level.
3. Fuel gauge stuck on full
And just the same as the fuel meter assembly can be stuck on empty, it can also be stuck on full. Again, a faulty fuel sending unit can cause the fuel meter assembly to malfunction and become stuck on full. A mechanical failure inside the instrument cluster can also cause the gauge to remain stuck on full, if it is a mechanical gauge style meter with a needle.
Due to the fact that the fuel meter assembly is often built into the cluster, and the component that controls it is located in the fuel tank, a faulty fuel meter assembly can often be difficult to diagnose. If you suspect that your vehicle’s fuel meter assembly may be having an issue, have the vehicle inspected by a professional technician, such as one from YourMechanic, to determine if gauge, or perhaps cluster, should be replaced.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Fuel Meter Assembly and was authored by Eduardo Ruelas.