Network Communication Diagnostic Trouble Codes

Complete list of Network communication DTC codes with free diagnostic guides.

Below you'll find every known DTC code for the Network Communication subsystem with step-by-step diagnostic and repair instructions. 9 guides are available — covering causes, symptoms, and repair costs. Use the table to find your specific code, or browse our full Network DTC code library for other subsystems.

DTC Code Meaning Severity Time

U0073 The engine control module (ECM) cannot talk to other control modules on Bus A. T... medium 30–60 minutes U0100 The U0100 code tells you that the engine control module (ECM) or power‑train con... medium 30-60 minutes U0101 The power‑train control module (TCM) cannot receive data from the engine control... medium 30‑60 minutes U0121 U0121 signals that the Engine Control Module (ECM) cannot exchange data with the... medium 30–90 minutes (diagnosis only) U0126 The PCM (power‑train control module) can’t receive data from the steering‑angle ... medium 30‑60 minutes U0128 The power‑train control module (PCM) cannot receive data from the park brake con... medium 30-60 minutes U0140 The U0140 diagnostic trouble code signals that the Powertrain Control Module (PC... medium 30-60 minutes U0155 The power‑train control module (PCM) cannot receive data from the instrument pan... medium 30‑60 minutes U1000 The power‑train control module (PCM) cannot receive or send data on the vehicle’... medium 30‑60 minutes

About Network Communication Trouble Codes

Network communication diagnostic trouble codes are triggered when the vehicle's onboard computer detects a malfunction in the communication subsystem. These codes help you quickly identify the problem without visiting a dealership. Our guides walk you through each DTC code with step-by-step diagnostic procedures, tools needed, and when to call a professional mechanic.

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