Fault code P2066 is called “Fuel Level Sensor “B” Circuit Range/Performance” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P2066
The OBD-II trouble code P2066 is defined as “Performance range mismatch in the “B” fuel reading sensor circuit”. Set when the Powertrain Control Module (PCM) detects a performance range mismatch from the fuel level sensor assembly.
The PCM does not initially know how much fuel is in the fuel tank. The only information the controller has about the fuel level is based on the signal voltage generated by the transmitting device.
Whether the tank is full or empty, the controller expects to see a predetermined signal voltage that corresponds to that condition. If, for example, a short circuit produces a resistance incompatible with either of these states, the controller will set code P2066 and turn on the signal lamp.
This error is an electrical fault, in other words, if the input circuit of the transmitting unit is fully functional, the code will not normally be set. If there is a mechanical problem preventing the float lever from moving. The fuel level gauge reading will simply not reflect changes in the actual fuel level in the tank.
If the fuel level signal to the fuel pump module does not match the operating range for a period of time. The module that controls the fuel level circuit will record this fault code.
Symptoms of vehicle malfunctions
The main signal that an error P2066 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The “Check engine” control lamp on the control panel will light up (the code will be recorded in the memory as a fault).
- The indicated fuel level may differ from the actual fuel level.
- The fuel level indicator may illuminate even though there is enough fuel in the tank.
- The engine may shut down even though the fuel level gauge indicates it is present.
The severity of fault code P2066 is low. The vehicle will be able to continue driving, but the driver will most likely not be able to accurately determine how much fuel is in the tank.
Factors that can cause this error code
The error code P2066 can mean that one or more of the following problems have occurred:
- Fuel level sensor malfunction.
- The fuel sensor signal circuit is open.
- Grounding circuit is open or has high resistance due to rust.
- Open circuit in fuel lever sensor resistor to earth.
- Damage to the fuel level sensor float.
- Damage to the fuel tank can cause problems in the fuel level circuit.
- Sometimes a faulty PCM module is the cause.
How to fix or reset OBD-2 code P2066
Some suggested steps for troubleshooting and fix the error code P2066:
- Read all stored error codes with an OBD-II scan tool.
- Then clear the error codes from the PCM memory and try to determine under what circumstances error P2066 first appeared.
- Check the operation of the fuel level sensor to see if it is giving the correct readings.
- Inspect the wiring, replace if necessary.
- If the problem persists, test the PCM module.
Diagnose and repair of problems
The fuel level sensor normally operates without failure during the life of the fuel pump. Therefore, if you still have code P2066, do a visual inspection of the fuel tank and wiring harness.
Look for damage to the tank indicating an impact that may have damaged the fuel pump or gauge. Inspect for the presence of ground arcs where the fuel tank is grounded to the frame and for excessive rust.
Check the wiring harness connector for damage, repair if necessary. Check that voltage is present at the fuel level gauge in the fuel pump wiring harness. If it is not present, repair the open or short in the wiring harness.
Perform a voltage drop test between the positive battery terminal and the ground on the vehicle frame. When testing for voltage drop, it should be about 0.1 volts.
Higher values indicate a fault in the input circuit. Repair or replace the wiring if necessary.
After checking the wiring, you should also check the fuel level sensor itself. These sensors are quite reliable, but sometimes it is because of a failed sensor that the error P2066 appears.
On which vehicles does this problem occur most frequently
Fault code P2066 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Chrysler (300C, Pacifica)
- Dodge (Charger)
- Jeep (Grand Cherokee)
- Mercedes-Benz (W211, W220)
Fault code P2066 can sometimes be found with other errors. The most common are the following: P2065, P2067, P2068, P2069.