U0109 on Buick
Lost Communication With Fuel Pump Control Module "A"
U0109 on Buick vehicles indicates lost communication with fuel pump control module "a". Au7o has documented this code across 1 Buick model — most commonly on Envision. 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. Typical repair costs on Buick range from $500 to $1,400, depending on the specific model and root cause.
Common Causes of U0109
- •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
U0109 on Buick by Model
Buick Envision(1 issue)
- Fuel Pump Control Module Failure Causing Stalling and Intermittent No-Start (Gen2 LSY)2021-2023
Second-generation Envisions have a repeating NHTSA pattern of the fuel pump control module failing, producing an engine that dies without warning while driving and a crank-no-start afterward, or that only fires on 7-8 of every 10 attempts. Owners report no warning lights and no stored codes in several cases. One especially dangerous report describes the vehicle stalling in a center freeway lane where the electronic shifter would not allow neutral with the engine off, stranding the car in traffic. Failures are documented from about 11,000 miles, and replacement modules have been back-ordered for extended periods.
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View U0109 across all makes →Frequently Asked Questions
What does U0109 mean on Buick?▼
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 Buick specifically, this code is documented across 1 model.
What causes U0109 on Buick vehicles?▼
Common causes on Buick: 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. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix U0109 on a Buick?▼
Repair costs on Buick range from $500 to $1,400, depending on the specific model and root cause.
Which Buick models have U0109 documented?▼
Au7o has documented U0109 on 1 Buick model: Envision.