What does it mean?
This code is stored when the gaseous fuel tank A level signal is present but jumps, cuts out or changes far faster than fuel can physically be consumed or added. The module knows the level should move slowly and smoothly, apart from a single step during refuelling, so a value that flickers between readings is a clear sign of a bad connection rather than a bad measurement. Level senders are especially prone to this because the wiper runs on a resistive track that wears and oxidises, and because the connector sits in an exposed underbody position. Fuel slosh can also make a worn sender break contact briefly during cornering and braking. The driver notices an unstable gauge and, on some systems, spurious low fuel warnings.
Symptoms
- Gas fuel gauge needle jumping or briefly dropping to empty, especially on corners and bumps
- Low fuel warning flashing on and off with fuel still in the tank
- MIL (check engine lamp) that appears and clears without repair
- Occasional unexpected changeover from gas to gasoline
- Range display fluctuating in an unrealistic way
- No fault reproducible with the vehicle standing still
Likely causes
- Worn or oxidised resistive track with the wiper losing contact intermittently
- Loose, corroded or fretted terminals in the level sender connector
- Water in the connector making and breaking a path as it moves and dries
- Chafed underbody harness touching ground only when the vehicle flexes
- Float arm hitting an obstruction or a baffle inside the tank, causing sudden jumps
- Intermittent open in the sender ground or a corroded ground stud
- Loose connector at the gaseous fuel control module
How to fix it
- Review the freeze frame data to see the driving conditions when the fault set
- Graph the raw level signal on a scan tool while wiggling the sender connector and the underbody harness
- Open the connector and check terminal tension, contact face condition and the seal, since water intrusion is a leading cause
- Where the sender is accessible, sweep the float through its full travel while watching resistance for dropouts and dead spots
- Inspect the harness for chafe points at brackets, straps and heat shields, and voltage drop test the ground while tapping the loom
- Repair or replace the affected terminals, reseal the connector and secure the harness, then road test over the conditions in the freeze frame
- Replace the level sender or multivalve assembly when the signal still drops out with a proven harness fitted