What Does U0109 Mean?
The vehicle's control network has lost communication with the fuel pump control module. This module manages fuel pump speed, pressure, and operation timing.
Safety Warning
Engine may fail to start or stall during operation due to improper fuel delivery. Critical safety concern if engine dies while driving, particularly in traffic.
Common Causes
35%
Damaged wiring or corroded connectors to fuel pump control module
30%
Failed fuel pump control module
20%
CAN bus network communication failure
10%
Power or ground circuit failure to fuel pump module
5%
Module programming issue or software corruption
Diagnostic Steps
1
Step 1: Check fuel pump fuses, relays, and verify power to fuel pump control module
2
Step 2: Inspect fuel pump module connector for corrosion, damage, or loose terminals
3
Step 3: Test CAN bus communication signals at fuel pump module location
4
Step 4: Monitor fuel pressure during cranking to verify pump operation despite communication loss
5
Step 5: Test fuel pump control module or replace if power, ground, and network tests pass
Estimated Repair Cost
$200 - $1,000
Parts + labor, varies by vehicle and location
The vehicle's control network has lost communication with the fuel pump control module. This module manages fuel pump speed, pressure, and operation timing.
The most common cause of U0109 (Lost Communication With Fuel Pump Control Module) is: Damaged wiring or corroded connectors to fuel pump control module
Typical repair costs for U0109 range from $200 to $1,000, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Engine may fail to start or stall during operation due to improper fuel delivery. Critical safety concern if engine dies while driving, particularly in traffic.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0109 to identify the root cause.
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Quick Info
Category
Network
System
Fuel System / Network Communication
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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