What it means
The vehicle bus reports loss of communication with smart fuel level sensor A. Tank gauge may freeze and low-fuel warnings may be incorrect.
At a glance
- Usually lights the warning light of the system that lost communication
How it works
Smart fuel level sensor A measures fuel in its part of the tank and sends that information over the vehicle network. U0676 sets when the receiving module stops getting messages from sensor A, so the displayed fuel level or low-fuel warning may be unreliable.
Common causes
Most likely first.
- Bus wiring open or shorted
- Module without power or ground
- Module failed
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Scan all modules for communication codes and save freeze-frame data before clearing faults, since other network codes may point to a shared power or bus problem.
- Compare the fuel gauge and low-fuel warning with the vehicle's known fuel level, and check live data for sensor A to see whether its reading is absent or frozen.
- Inspect the sensor A connector and accessible wiring for corrosion, loose pins, damage, or signs of fuel-tank or recent repair work.
- Check sensor A's power and ground against the manufacturer's specification.
- Test the network wiring to sensor A for an open or short using the manufacturer's procedure.
- If the bus and supply circuits are sound, use the manufacturer's diagnostic procedure to confirm whether sensor A or its module has failed.
Common fixes
- Reconnect or clean the fuel level sensor A connector and repair damaged wiring.
- Restore the sensor or module's faulty power or ground connection.
- Repair an open or short in the network wiring to sensor A.
- Replace the failed fuel level sensor A or its communication module after testing confirms the fault.
Can I keep driving?
You can generally drive if the vehicle runs normally, but do not rely on the gauge or low-fuel warning; refuel early and track mileage until the reading is restored. Running out of fuel can leave you stranded and may interrupt engine operation.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.