A check engine light means the engine computer has logged a fault it cannot correct on its own. AutoTech Clinic reads the stored codes, looks at the live sensor data and freeze frame, and tests the circuit the code points at so you replace the part that actually failed. We do this at our shop on Michigan Ave at Telegraph in Dearborn, usually the same day.
If the light is flashing rather than steady, the engine is misfiring badly enough to damage the catalytic converter. Pull over when it is safe and call (313) 277-7200.
- How Long
- About 1 to 2 hours of diagnostic time for most faults.
- Same Day
- Usually finished the same day.
- Vehicles
- Foreign and domestic, cars through trucks.
Signs You Need Check Engine Light Diagnostics
- A steady amber engine light on the dashboard
- A flashing engine light, which means stop driving
- Rough idle, hesitation or a loss of power with the light on
- A failed emissions test or a readiness monitor that will not set
- Fuel economy that fell off noticeably
- A rotten egg smell from the exhaust
What We Do
- 01
Pull Codes and Freeze Frame
We read every module, not just the engine computer, and capture the freeze frame data that shows what the engine was doing the moment the fault set.
- 02
Verify the Complaint
We drive the car under the same conditions that set the code. A fault that only appears cold or under load has to be seen to be diagnosed.
- 03
Test the Circuit
We test the sensor, its wiring and its ground with a meter or a scope. Codes point at a circuit, and the failure can be anywhere in it.
- 04
Check the Mechanical Side
Many codes are set by mechanical problems: a vacuum leak, low compression, a stretched timing chain or a clogged exhaust. We rule those in or out before condemning a sensor.
- 05
Quote, Repair and Verify
You get a clear explanation and a price. After the repair we clear the codes, run the vehicle through a drive cycle and confirm the monitors complete and the light stays off.
Why the Same Code Can Mean Different Repairs
Take P0420, the most common code we see. It says the catalytic converter is not working as efficiently as the computer expects. That can mean a failed converter, but it can also mean a lazy oxygen sensor, an exhaust leak ahead of the sensor, or an engine running rich from a different fault entirely.
Replacing the converter without testing is how people spend a great deal of money and still have the light on a week later. We test the sensor response, check for leaks and look at fuel trims first.
What We Tell You
You get the code number, what it means in plain words, what we tested, what we found and what it costs to fix. If there is more than one way to approach the repair we lay out both with the trade-offs.
If the fix is something simple you can do yourself, like a fuel cap that is not sealing, we will tell you that too.
What Affects the Cost
We quote your vehicle specifically after inspecting it, because these are the things that move the number up or down:
- How many systems are involved and whether there are multiple unrelated codes
- Intermittent faults that only appear under certain conditions
- Whether the repair is a sensor, a wiring fault or a mechanical problem
- Access to the failed part, which varies hugely between engines
- Whether a module needs programming after replacement
Call (313) 277-7200 with your year, make and model and we will tell you what to expect before you come in.
Why AutoTech Clinic
AAA Approved
An inspected facility that has to meet AAA standards for equipment and training.
Photos First
You see what we found and approve the price before anything is taken apart.
Same-Day Service
Parts on hand for the vehicles we see most, so you are not waiting on a delivery.