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critical Buick

Error Code $F$U

Low fuel warning - indicates imminent depletion of engine tank resources requiring immediate refueling.

? What Causes This

Fuel gauge malfunction, low actual fuel level in the tank.

How to Fix It

Refuel as soon as possible or contact roadside assistance if unable to reach a station safely.

Source: page 144 of the official manual

From the manual

Manual page 144 — Buick error $F$U

This error code appears in:

Buick Enclave