ECU has detected a problem

The ECM monitors the vehicles systems and makes adjustments. If a certain problem has occurred, the ECM will store a problem code, and illuminate a "Check Engine" or "Service Engine Soon" light. A mechanic can read the stored code and quickly determine the source of the problem.

Table of Contents

• 1. Symptoms
  • 1.1 Check Engine Light is On

Symptoms

Check Engine Light is On

The "Check Engine" light, "Service Engine Soon" on some vehicles, is designed to inform the driver that the vehicle computer has detected a problem with one of the various systems.