Diagnostics / Mississauga
A code points at a circuit, not at a part
P0171 doesn’t mean “buy an oxygen sensor”. It means the engine is running lean, which could be a vacuum leak, low fuel pressure, a dirty mass air flow sensor or an exhaust leak upstream of the sensor. Free code reads exist to sell parts. Diagnosis exists to fix cars.
Don’t clear the code before you come in. Freeze-frame data — the conditions recorded at the moment the fault set — is often the most useful thing we have. Clearing it throws the evidence away and resets the readiness monitors.
01 / Method
What ninety minutes buys you
Full-system scan
Every module, not just the engine. ABS, transmission, body, airbag. Manufacturer-level software, not a generic reader that speaks four codes.
Freeze-frame and history
Engine temperature, load, speed and fuel trims at the moment the fault set. This is where most of the answer usually is.
Live data under load
Watching sensors work is different from reading what they last reported. Fuel trims and misfire counters tell a story a static scan can’t.
Oscilloscope where needed
Intermittent electrical faults and sensor signal problems are invisible to a scan tool. A scope shows the actual waveform.
Road test
If the fault only happens at 90 km/h in fourth gear, that’s where we go and find it. With the scan tool logging.
Written finding with photos
What’s wrong, what it costs, what happens if you leave it. Yours to keep whether or not we do the work.
02 / Price
Diagnostic fees
| Type | Price |
|---|---|
| Standard diagnosis — scan, freeze-frame, live data, report | $119 |
| Extended diagnosis — scope work, road test logging (up to 3 h) | $260 |
| Electrical fault trace, per hour after the first | $130 |
| EVAP smoke test | $135 |
| Cooling system pressure test | $95 |
| Compression and leak-down test | $180 |
| Data logger fitted for several days | quoted |
| Second-opinion review of another shop’s quote | $119 |
03 / Coverage
What we can actually talk to
Manufacturer-level scan tool coverage matters more than any other tool in the building. It’s the difference between reading a fault and being able to code, adapt and program the module that caused it.
European
German, Swedish and British makes including coding, adaptations and service resets.
Japanese & Korean
Full system access, key programming and immobiliser work on most models.
Domestic
North American makes including module programming and bidirectional tests.
Hybrid
High-voltage system scanning and battery health reporting. We don’t open packs.
If we can’t communicate with a system on your vehicle, we’ll tell you before you leave the car — not after billing you an hour for finding out.
Questions
The fair objections
Why pay when the parts store reads codes free?
Because reading and diagnosing are different jobs. The free read is a sales tool — it names a code, and the counter names a part. If the part is wrong you’ve paid more than the diagnosis would have cost and still have the fault.
Should I clear the code first?
No. You erase the freeze-frame data and reset the readiness monitors. It’s the automotive equivalent of wiping the scene before the inspection.
What if you can’t find it?
Some intermittent faults need a logger fitted for a few days. We’ll tell you what we ruled out, what it cost, and what the next step is. We won’t start replacing parts to keep the invoice moving.
Do I get the diagnostic fee back?
It’s credited in full against the repair if we do the work. If you decide not to proceed, you keep the written findings and the photos and you’re free to take them anywhere — including to the shop that quoted you first.
Can you check a car another shop has quoted on?
Yes, that’s a common request. $119 for an independent review of their quote and our own findings, in writing.