Symptoms
Symptoms of a DTC P2068 may include:
- MIL (Malfunction Indicator Light) illumination
- Fuel gauge may fluctuate abnormally or read empty or full
- Fuel warning light may come on and trigger an alarm
Causes
Potential causes of a P2068 code include:
- Signal circuit to fuel sender is open or shorted to B+ (battery voltage)
- Ground circuit is open, or ground path may have high resistance due to rust or missing ground strap on fuel tank
- Damage to fuel tank could cause issues in fuel level circuit
- There is an open in fuel level sensor resistor to ground
- Dashboard cluster may be faulty
- Less likely is the possibility of PCM, BCM, or fuel pump module failure
Possible Solutions
Fuel pump senders typically last the lifespan of the fuel pump. So if you have this code, perform a visual inspection of the fuel tank and wiring harness. Look for tank damage indicating an impact that may have damaged the fuel pump or sender. Check for missing ground strap or rusty ground where the fuel tank connects to the chassis. Ensure the wiring harness connector is not damaged. Repair as needed. Identify the type of system you have and verify that fuel level sensor voltage is present at the fuel pump wiring harness. If not, repair the open or shorted wire.
Performing a voltage drop test on the ground circuit can determine if there is a high-resistance path in the ground circuit. You can perform this using a voltmeter by connecting one lead to the battery ground terminal and the other to the fuel level sensor ground in the tank. Turn the key (preferably with engine running). Ideally, it should be 100 millivolts or less (0.1 volt). Anything approaching 1 volt indicates a current or developing problem. Repair/clean the fuel level sensor ground as needed. It’s not impossible for the instrument cluster to have failed internally or on the circuit board (if applicable). These are very difficult for a layperson to test. But if you have access to a wiring diagram, you may be able to remove the cluster and see damaged circuitry if it’s on the circuit board, otherwise you’ll need a scan tool that can communicate with the instrument cluster.
A simple way to test the fuel level circuit is to provide a good ground to the fuel level sensor at the fuel tank connector. With the key on, the fuel gauge should go to one extreme or the other. Completely removing the ground path should result in the opposite. If the gauge responds, you know the wiring providing voltage and ground to the fuel level sensor is good and the instrument cluster is likely correct. The probable suspect would be the fuel level sensor itself. It may be necessary to remove the fuel tank to access the fuel pump module inside. PCM or BCM (Body Control Module) failure is not impossible but highly unlikely. Don’t suspect these first.