Chevrolet and GMC HD Trucks Face Fuel Gauge Issue, Again
Chevrolet Silverado 3500 HD and GMC Sierra 3500 HD trucks equipped with the 6.6-liter L8T V8 gasoline engine are experiencing a problem where the fuel gauge inaccurately indicates remaining fuel, potentially leading to the engine stalling. This issue mirrors a similar problem that affected trucks with the 6.6-liter Duramax L5P V8 turbo-diesel in 2024.
The Problem: Running on Empty When the Gauge Says Otherwise
According to GM Service Bulletin PIT6467A, dated February 2026, affected trucks “run out of fuel with the fuel gauge indicating there is still fuel in the tank,” and the “fuel gauge [may] default to empty, but there is still fuel in the rear tank.” The Service Bulletin also notes that the check engine light (SES MIL) may illuminate without affecting drivability. The root cause appears to be a failure in the fuel transfer system, specifically, “the rear tank is not transferring fuel to the front tank.”
Which Trucks Are Affected?
The issue specifically impacts chassis-cab versions of the 2025 and 2026 Chevrolet Silverado 3500 HD and GMC Sierra 3500 HD trucks that arrive standard with dual fuel tanks (RPO code N2N). These trucks have a combined fuel capacity of 63.5 gallons, split between front and rear tanks.
GM’s Response: Investigation Underway
Currently, General Motors has not issued a fix for this problem. The Service Bulletin instructs mechanics not to replace any parts, as engineering teams are actively investigating the cause. GM states that the Preliminary Information (PI) will be updated or replaced with a Technical Service Bulletin (TSB) once a solution is determined. This means GM does not yet know the underlying reason for the inaccurate fuel readings, and stalling.
What Does This Mean for Owners?
Owners of affected Chevrolet Silverado 3500 HD and GMC Sierra 3500 HD trucks may want to closely monitor their fuel gauges and consider keeping their tanks closer to full until a fix is available. The cause of the issue could be a defective part, an assembly defect, or a combination of factors.