Causes and Fixes U0109 Code: Lost Communication with Fuel Pump Control Module

How to fix a U0109 Code: Lost Communication with Fuel Pump Control Module
A U0109 code is set when the vehicle's main computer (ECM/PCM) cannot communicate with the Fuel Pump Control Module (FPDM).
Older vehicles use a fuel pressure regulator to control fuel pressure which the FPDM has replaced.
The FPDM controls voltage to the fuel pump which controls how much pressure it sends to the engine.
The FPDM receives inputs from various sensors and input from the vehicles main computer (ECM/PCM) to calculate voltage output.
Its location varies depending on the vehicle, but it’s usually at the back of the car.
A Fuel Pump Control Module (FPDM) is also called a Fuel System Control Module (FSCM)

Possible Causes of a U0109 Code:
Bad Fuse or Relay
Bad Wiring (Open/Short)
Bad Fuel Pump Control Module
Computer Issues with ECM/PCM


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