01 / DiagnosticsDorchester, MA 02124

Full vehicle diagnostics in Dorchester

A warning light tells you something is wrong. It does not tell you what. We run advanced diagnostics to detect the issue, from engine codes to electrical faults, and give you fast, accurate answers so you know exactly what your car needs before anything gets replaced.

Hours Mon–Fri 8:30 AM–6:30 PMSat 8:30 AM–5:10 PMSun closed

Illustration: a gloved hand holding a scan tool plugged in under a car's dashboard, with a graph on its screen.
Illustration of a scan tool under a dashboard. AI illustration, not Petty's shop.

What's included

Read the codes, check the electrics, explain it.

  1. 01Reading and interpreting engine codes. We plug into the car, pull the stored codes and read what they point to, not just what they say.
  2. 02Checking for electrical faults. Lights that flicker, accessories that cut out, a battery that keeps dying: we check the electrical side as part of the same visit.
  3. 03A plain-language explanation. What we found, what the car needs, and what can wait. In English or Spanish.

What to expect

Any charge to diagnose is told to you before we start, and you get the result explained before anything is replaced. A code is where the diagnosis starts; it is not a repair, and it is not a price. You decide what to do next.

Signs you need this

What the car is telling you.

  • The check engine light is on. Steady means get it checked soon. Flashing means a misfire is happening right now: pull over when it is safe and do not keep driving on it, because an active misfire can destroy the catalytic converter. Urgent
  • Any other dashboard light. ABS, battery, oil pressure, traction control.
  • Rough idle, hesitation, stalling or lost power. The engine is not running the way it should and a scan is the fastest way to find out why.
  • Electrical things act up. Lights flicker, windows slow down, accessories cut out.
  • The light is on and the sticker is due. For vehicles that need the Massachusetts OBD emissions test, a lit check engine light means the car does not pass that part of the annual inspection, so it needs to be looked at before the inspection, not after. Which vehicles are tested (Massachusetts Vehicle Check)

What a scan reports

A code is a starting point, not a verdict.

These are standard examples of what a diagnostic reports (generic OBD-II definitions, SAE J2012). The same code can have several causes; the diagnosis is the work of finding which one.

Diagnostic readoutExample

  • P0300Random or multiple cylinder misfire detected
  • P0420Catalyst system efficiency below threshold
  • P0562System voltage low
  • P0171Fuel system too lean

Questions people ask

About diagnostics.

My check engine light is on. Can I keep driving?

If it is steady, get it checked soon; the car is telling you something is off. If it is flashing, that is an active misfire: pull over when it is safe and call us, because driving on it can damage the catalytic converter, which is an expensive part. Either way, a diagnostic tells you exactly what is going on.

How much does a diagnostic cost?

Call (857) 756-0675 and tell us what the car is doing; we will tell you what to expect before you come in. Any charge to diagnose is told to you up front, and you get a written estimate before any repair work starts.

Do you speak Spanish?

Yes. You can call, message and get your explanation in Spanish, and this whole site is in Spanish too.

Light on and the engine running rough? See engine repair

All questions

Light on?

Call (857) 756-0675 or request a diagnostic. We answer in English or Spanish.

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