P2066 indicates that the Powertrain Control Module (PCM) has detected a performance issue with the Fuel Level Sensor B circuit. This usually means the sensor's signal is out of expected range or unstable, causing the fuel gauge to read incorrectly or the PCM to question the fuel level data.
The sensor itself may have a worn resistive track, stuck float, or internal short/open, causing an out‑of‑range signal to the PCM.
Corrosion, loose pins, chafed wires, or a broken harness can interrupt or distort the sensor's voltage signal.
Debris, fuel varnish, or a bent float arm can prevent the sensor from moving freely, producing erratic readings.
Though uncommon, a damaged input pin or internal PCM circuitry that processes the sensor signal can cause a false performance code.
Improperly installed fuel pump modules, tank accessories, or wiring splices can alter the sensor's reference voltages.
No. The PCM is rarely the cause of this code; most cases are due to a faulty sensor, wiring, or float mechanism. Replacing the PCM without first testing the sensor and circuit usually does not resolve the issue.
Yes, the vehicle will typically run normally, but the fuel gauge may be unreliable, increasing the risk of running out of fuel unexpectedly.
Clearing the code only turns off the Check Engine Light; if the underlying sensor or wiring fault remains, the code will likely return.