Repair Guides
Check Engine Light On? What It Means and What to Do Next
By the JCo Auto Service Team · Reviewed by our Red Seal journeyman mechanic
Published September 20, 2026 · 2 min read
Quick answer
If your check engine light is steady, book a diagnostic soon. If it's flashing or the car is running badly, stop driving and call us — it can cause more damage. A steady light usually isn't an emergency, but it shouldn't be ignored.
Steady vs flashing check engine light
A steady check engine light means the car's computer has found a problem it wants you to know about. It's usually safe to keep driving short distances, but you should book a diagnostic soon.
A flashing check engine light is more serious. It often means the engine is misfiring badly enough to damage the catalytic converter. If it's flashing or the car is shaking, running roughly, or losing power, pull over safely and call us at (403) 287-0337.
Common causes (in general terms)
The check engine light can come on for many reasons. Some are simple; some aren't. Common causes include:
- A loose or missing gas cap
- A failing oxygen (O2) sensor
- Spark plug or ignition coil problems (misfires)
- Emissions-system parts like the catalytic converter or EVAP system
- A mass airflow sensor issue
Why a code isn't a diagnosis
A code reader tells you which system the computer flagged — not which part is actually broken. For example, an oxygen sensor code doesn't always mean the sensor is bad; it can mean something upstream is causing a bad reading. Replacing parts based on a code alone often wastes money.
That's why we test to find the real cause before recommending any repair. You only pay for what your car actually needs.
What to note before you come in
A few details help us diagnose faster. Before you bring your car in, note:
- Is the light steady or flashing?
- Does the car run differently — rough idle, hesitation, loss of power?
- When did it start — after refuelling, on a cold start, on the highway?
- Has your fuel economy dropped?
What our diagnostic process looks like
We scan the codes, then test the related systems to confirm the real cause — not just the first thing the computer points to. Then we explain what we found in plain words and give you the price before any work starts.
If it's something simple like a gas cap, you'll know right away. If it's bigger, we'll lay out what needs doing now and what can wait. Book an Engine Diagnostics and Check Engine Light or walk in Monday to Friday, 9 to 5.
Engine Diagnostics and Check Engine Light
Walk-ins welcomeWalk-ins welcome Monday to Friday, 9 am to 5 pm. Calling ahead is advised.
Frequently asked questions
Is a code reading the same as a diagnosis?+
No. A code points to a system; testing finds the actual cause. We test before recommending any repair so you only pay for what your car needs.
Can I keep driving with the check engine light on?+
If it's steady and the car drives normally, you can drive short distances but book a diagnostic soon. If it's flashing or the car runs badly, stop driving and call us — it can cause more damage.
Can I walk in for a diagnostic?+
Yes. Walk-ins are welcome Monday to Friday, 9 am to 5 pm. Calling ahead at (403) 287-0337 is advised so we can get you in quickly.
Related services
Engine Diagnostics and Check Engine Light
Computer diagnostics that find the real cause behind the code.
Learn more →Engine Repair
Engine diagnostics and repair, from minor fixes to major engine work.
Learn more →Spark Plug Replacement
Spark plug replacement to fix rough idle, misfires, hard starts and poor fuel economy.
Learn more →Keep reading
Ready when your car needs us
Walk in Mon–Fri 9–5, call (403) 287-0337, or book online in under a minute.