Code Definition

U0109 — Lost Communication with Fuel Pump Control Module

System: Network Communication  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About U0109

U0109 is a generic (obd-ii standard) network communication diagnostic trouble code. It belongs to the U-prefix family of codes, which covers inter-module network communication (CAN, LIN, FlexRay, or similar) faults.

Scanning & clearing: Network (U) codes report communication faults between modules. When diagnosing U-codes, checking the vehicle's CAN bus integrity, supply/ground at each module, and reading all modules for related faults is usually the first step.

Because U0109 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

DTC U0109 indicates lost communication with the Fuel Pump Control Module. The Powertrain Control Module, and on some vehicles the Body Control Module, communicates with the Fuel Pump Control Module over the CAN network to command and monitor fuel pump operation. The code sets when valid messages from the Fuel Pump Control Module are not received within a calibrated time while the ignition is in run or start. This usually means the module has lost power or ground, or the CAN connection to it is faulty, rather than a simple sensor problem. Because the module controls fuelling, the result is ofte...

Join TaT to view the complete code information and diagnostic details.

Quick Facts