---
id: department-0009
title: "What should I do if my check-engine light comes on?"
category: department
subtopic: service-diagnostics
page_type: department
source_url: "https://www.castlechevymchenry.com"
tags: ["service", "diagnostics", "troubleshooting"]
questions:
  - "What does the check-engine light mean?"
  - "How do you diagnose engine problems?"
  - "Should I be worried if my check-engine light is on?"
related: [service-maintenance, service-recalls]
dealer: Castle Chevrolet McHenry
---

A check-engine light signals that your vehicle's onboard diagnostic system has detected a fault-sometimes minor, sometimes serious. It might be a loose gas cap, a faulty sensor, or something requiring immediate attention. The point is: don't ignore it.

At Castle Chevrolet McHenry, we read the diagnostic trouble code(s) stored in your engine computer to pinpoint the issue. Our technicians then explain what's happening and what repair is needed. Modern diagnostics are precise, saving time and money by targeting the actual problem rather than guessing.

Early diagnosis prevents small issues from becoming expensive repairs and keeps your vehicle running clean and efficiently.

**See a check-engine light?** Call (779) 600-2956 and schedule a diagnostic visit. We'll have answers and a plan.