P2065 indicates a problem with the secondary fuel level sensor circuit, often referred to as Sensor B. The powertrain control module (PCM) has detected that the electrical signal from this sensor is out of its expected range, missing, or irrational.
The sending unit inside the fuel tank is the most common failure point, typically due to wear on the resistor card or a stuck float.
Corroded, chafed, or disconnected wiring and connectors between the sensor and the PCM can disrupt the signal.
Though less common, an internal fault in the gauge cluster can prevent it from properly interpreting the sensor signal.
A failed powertrain control module is highly unlikely and should only be considered after all other components are definitively ruled out.
No, it is extremely rare for the PCM to cause P2065. Despite what some advice might suggest, the problem is almost always a failed fuel level sensor or a wiring issue, not the engine computer.
It is typically the fuel level sensor in a secondary fuel tank on vehicles equipped with dual tanks, or a redundant sensor used to cross-check the primary fuel level in a single tank.
Yes, the vehicle will generally run and drive normally. However, you will not have an accurate reading of your fuel level, which could result in unexpectedly running out of gas.
You can test the sensor directly at the fuel tank connector by checking its resistance while moving the float up and down. If the resistance changes smoothly, the sensor is good and the fault likely lies in the wiring.