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U0100

Overview

Code

U0100

Code Type

U

Code Class

U0

System

Network

Severity Level

High

Emissions Related

false

Drivability Impact

Major

Diagnostic Protocol

CAN

Freeze Frame Useful

false

Code Definition

Diagnostic trouble code U0100 indicates lost communication with the engine control module (ECM/PCM)

Symptoms

No start; Multiple warning lights

Overview applies to this diagnostic code.

Affected Systems

On This Page

  • Code Definition

  • Symptoms

  • Affected Systems

  • Possible Causes

  • Diagnostic Steps

  • Drive Safety Notes​

More Resources

Vehicle network communication

Possible Causes

CAN bus wiring fault; ECM power loss

Diagnostic Steps

1 Check ECM power and ground; 2 Inspect CAN bus integrity

Drive Safety Notes

Vehicle may not start or operate

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