U0109 on Chevrolet: How to Diagnose & Fix
Lost Communication With Fuel Pump Control Module "A"
1 Chevrolet model · 1 documented issue · $250-$600 repair
U0109 on Chevrolet by model: symptoms, diagnosis and fix
GMT900 Silverados (and the late GMT800) mount the fuel pump control module / fuel-system control module on an exposed frame-rail bracket where it is constantly hit with road salt, water and debris. The module's connector and internals corrode, and the FPCM then fails to drive the in-tank pump — producing extended cranking, intermittent stalling, and ultimately a crank-but-no-start with no fuel pressure. Because the pump itself is often fine, owners frequently mis-diagnose and replace the in-tank pump first. A common, well-documented salt-belt failure with steady search demand.
Common Symptoms
- Crank but no start / engine won't fire
- Extended cranking before starting
- Intermittent stalling while driving
- No fuel-pump prime sound at key-on
- Loss of power / hesitation
- Fuel-system codes / pump not commanded on
How to Fix
Diagnose by checking for fuel-pump prime/pressure and FPCM communication and inspecting the frame-mounted module connector for corrosion. The fix is to replace the corroded fuel pump control module (a new programmed module is required; GMT900 OE 20759945 / later 13543038 family) and clean/repair the connector and grounds; relocating or sealing the connector helps prevent recurrence. Rule out blown fuse/relay and a genuinely failed in-tank pump first.
Sources for this issue (1)
U0109 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does U0109 mean on a Chevrolet?
U0109 stands for "Lost Communication With Fuel Pump Control Module "A"." Sets when a module loses data-bus communication with the Fuel Pump Control Module 'A', which regulates electric fuel pump operation/pressure. Loss of these messages can interrupt fuel delivery. On Chevrolet it is documented across 1 model: Silverado.
What are the most common causes of U0109?
The most common causes of U0109 are: Open, shorted, or chafed bus wiring to the fuel pump control module, Corroded or loose module connector / poor ground, Blown fuse / lost power feed, Low battery voltage, Failed fuel pump control module. The specific cause varies by vehicle.
How much does it cost to fix U0109 on a Chevrolet?
Published repair estimates on Chevrolet range from $250 to $600 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.