When your check engine light comes on, the first thought isn’t usually “what’s wrong” — it’s “how much is this going to cost?” At Faithfull Tirecraft, we get that. Our job is to give you a straight answer as quickly as possible, with the evidence to back it up, so you can make an informed decision before anything gets touched.
Our journeyman-certified technicians use professional OBD-II diagnostic scanning equipment to read fault codes, interpret what’s actually causing them, and identify the fastest path to a fix — without recommending repairs you don’t need. Our staff isn’t on commission. That matters when someone is standing in front of a check engine light.
What is Engine Diagnostic Testing?
Modern vehicles are managed by an onboard computer system — the ECU (engine control unit) — that monitors hundreds of sensors across your engine, transmission, exhaust, and electrical systems. When something falls outside the normal range, the system stores a diagnostic trouble code (DTC) and triggers a warning light on your dashboard.
A professional diagnostic scan connects to your vehicle’s OBD-II port, retrieves those codes, and gives a technician the starting point to find the root cause. The codes narrow down the problem — but interpreting them correctly, and distinguishing a real fault from a false positive, is where experience counts.
Common Reasons Your Check Engine Light Comes On
The check engine light can trigger for dozens of reasons. Some are minor. Some aren’t. Common causes include:
- Loose or faulty gas cap — a small evaporative leak can set off the sensor
- Oxygen sensor failure — affects fuel mixture, fuel economy, and emissions
- Catalytic converter degradation — reduces emissions control and triggers codes
- Worn spark plugs or ignition coils — causes misfires, rough idle, power loss
- Mass airflow sensor issues — affects how your engine calculates fuel delivery
- Evaporative emission system leaks — often subtle, but persistent
- Transmission fault codes — shifting problems, fluid issues, solenoid faults
Even if the car feels fine, a stored code means something is out of range. Leaving it undiagnosed can turn a minor sensor issue into a more expensive repair down the road.
How We Handle It
We don’t just read codes and hand you a printout. Our diagnostic process is designed to find the actual cause, not just the symptom the code is pointing to.
- OBD-II scan — we retrieve all stored and pending fault codes from your vehicle’s computer
- Code interpretation — our technicians identify what each code means in context, not just in isolation
- Visual and physical inspection — we check related components: wiring, sensors, connectors, fluid levels
- Live data review — real-time monitoring of air/fuel ratios, RPMs, sensor readings, and more
- Plain-language explanation — we tell you what’s wrong, why it matters, and what we recommend
- Digital Vehicle Inspection — before any repair is approved, we send you photos and video of what we’re seeing so you can see it too
You don’t have to approve of anything blindly. That’s how we work.
What the Warning Light is Telling You
Not all check engine lights are equal:
- Steady light: Something is out of range and should be checked soon — not an emergency, but don’t ignore it
- Flashing light: A serious fault, often an active engine misfire. Continued driving can damage the catalytic converter. Come in as soon as it’s safe to do so.
- Light with performance loss or rough running: Your vehicle may have entered a reduced-power mode to protect the engine — get it diagnosed before driving further
If you’re unsure, call us. We’d rather talk you through it than have you make the wrong call on the road.
Systems We Diagnose
Our scanning and testing equipment covers all major vehicle systems, including:
- Engine performance and ignition systems
- Fuel injection and air intake
- Exhaust and emissions control (including catalytic converter and oxygen sensors)
- Transmission fault codes (note: we diagnose transmission issues but do not rebuild transmissions)
- ABS, traction control, and stability systems
- Charging system — battery, alternator, and starter
- HVAC and climate control systems
- Electrical faults and wiring issues
We work on all makes and models — domestic, import, and hybrid.
Frequently Asked Questions
What should I do when my check engine light comes on? If the light is steady and the car drives normally, schedule a diagnostic appointment soon. If the light is flashing or the car is running rough, don’t push it — come in or call us for guidance.
How long does a diagnostic take? Most scans and initial assessments take 30–60 minutes. More complex electrical or intermittent faults can take longer to pin down accurately.
Can I drive with the check engine light on? Depends on what it’s for. A steady light with no other symptoms is usually okay for short distances. A flashing light is not — continued driving risks serious engine damage.
Will you fix it the same day? If parts are available and the repair is straightforward, often yes. If it requires sourcing parts or more time, we’ll give you a clear timeline before anything begins.
Can I clear the code myself? You can disconnect the battery or use a consumer scan tool to clear the code, but if the underlying issue isn’t fixed, it will come back. Clearing the code also resets your emissions readiness monitors, which affects SGI inspections.
Do you charge for a diagnostic? Yes — a diagnostic is a billable service. If you proceed with the repair at Faithfull, the diagnostic fee is typically applied toward the repair cost. We’ll tell you the cost upfront before we start.
Book Engine Diagnostics in Saskatoon
If your check engine light is on, something’s changed in how your vehicle is running, or you just want to know what’s going on under the hood — bring it in. We’ll give you a straight answer.
Call us at 306-700-5295 or book online. Monday to Friday, 8:00am to 5:00pm.
Faithfull Tirecraft Saskatoon 837A 50 St E, Saskatoon, SK S7K 3Y5