Remote OBD-II Diagnostics

Know what's wrong
before you touch a wrench.

Send us your fault codes and symptoms. A real, professional mechanic reviews them personally and replies in plain English, not an automated code lookup, no garage visit, no guessing at parts.

See the service levels

P0301 · P0420 · P0171 · U0100, whatever your scanner shows, we can work with it.

No garage visit

Everything happens online or over a call, your car doesn't move.

A real mechanic reads your codes

Fault codes point at a system, not a part. A professional mechanic reasons through what's actually likely, not an automated code-to-text tool.

Know before you spend

Get a fault-finding plan before you pay a shop to start swapping parts.

Process

How a request moves.

Choose a service level

Quick Diagnosis, Detailed Diagnostic, or a Voice Call, pick what fits the situation.

MOST THOROUGH QD-1 Quick £20 DD-2 Detailed £40 VC-3 Voice £50

Send codes & symptoms

When you book, you add your fault code(s), the vehicle, and what it's doing.

FAULT CODES P0301 P0171 VEHICLE 2014 Ford Focus 1.6 TDCi SYMPTOMS Rough idle when cold, engine light came on after a motorway run…

We review off-line

A professional mechanic works through the codes against your symptoms, no live wait needed.

DIAGNOSTIC NOTES P0301 Misfire · cylinder 1 Ignition coil ✓ Spark plug Injector

Get your answer

A written diagnosis and plan land in your inbox, or you get your booked call.

TO you@example.com Your diagnosis, Ford Focus Most likely: ignition coil, cylinder 1. NEXT STEPS 1. Swap the coil with cylinder 2 2. Clear the codes, drive, re-scan 3. If the misfire follows → new coil

Service levels

Pick how deep you need to go.

All three start the same way, you tell us the codes and what the car is doing. Every request is read and answered personally by a professional mechanic, never generated automatically. Each service is capped per hour to keep replies fast, if a service shows sold out, the next hour's slots open automatically.

REF · QD-1

Quick Diagnosis

A fast read on what your codes likely mean.

  • You send your fault code(s) and a description of the symptoms
  • Limited to 5 new requests per hour, to keep replies quick
  • You get back the most likely causes and sensible next steps
£20.00 per request
Book & pay · £20.00
Most thorough
REF · DD-2

Detailed Diagnostic

A full fault-finding plan, not just a guess.

  • You submit your fault codes, symptoms, and any history that's relevant
  • Limited to 1 new request per hour, so it gets proper attention
  • We build an in-depth diagnosis and a step-by-step fault-finding plan, with diagrams for mechanical and wiring checks
£40.00 per request
Book & pay · £40.00
REF · VC-3

Voice Call Session

Talk it through with someone, live.

  • A direct one-on-one call, 30 minutes
  • Booked in one-hour slots, Mon–Fri 11:00–20:00, great for after work
  • Walk through symptoms, codes, and what you've tried in real time
£50.00 / 30 min call
Book & pay · £50.00

Membership

Keep a mechanic on hand.

Priority replies and lower prices on every diagnosis. Pick the length that suits you. The longer you commit, the less you pay, and the more you get.

MONTHLY

£14.99/mo

Rolling. Cancel any time

  • Priority responses, ahead of the queue
  • Member rates on every diagnosis (£15 / £35 / £40)
Choose monthly
SAVE £12

6 MONTHS

£12.99/mo

£77.94 paid once

  • Everything in Monthly
  • 1 free Quick Diagnosis when you join
Choose 6 months
BEST VALUE SAVE £60

12 MONTHS

£9.99/mo

£119.88 paid once

  • Everything in Monthly
  • 1 free Quick Diagnosis
  • 1 free Detailed Diagnosis
Choose 12 months

The Startup Kit

New to this? Start with the kit.

A plug-in Bluetooth OBD-II scanner delivered to your door, plus 6 months of membership and a free Quick Diagnosis. One payment, everything you need to read and understand your own car.

£120 one payment. Save around £40 versus buying separately.
Get the Startup Kit

Just want the scanner? OBD-II Bluetooth Scanner for £80.

First Diagnostics Startup Kit

FAQ

Before you send codes over.

Can you really diagnose a car remotely?+
Yes. Every car built since around 2001 constantly monitors itself and stores fault codes in its onboard computer. You read those codes with an inexpensive plug-in scanner (or most garages will read them for a couple of pounds), send us the codes plus a description of what the car is doing, and a real, qualified mechanic tells you in plain English what they mean and what to check next. It's the same read a garage does when they plug it in, without the call-out fee or the half-day off work. And if we can't give you a useful diagnosis, you don't pay.
A fault code points at one part. Do you just tell me to replace it?+
Never. A code flags the circuit or system, not always the exact culprit. A cam-sensor code is often a broken wire rather than the sensor; a MAF code can be an air leak or a sticking EGR valve; a rear ABS fault is often a corroded wire or a worn wheel bearing, not the sensor. We tell you what to check before you spend, the exact tests in the right order, so you or your mechanic confirm the real fault instead of throwing money at a part the code merely points at.
What do I actually get, and what does it cost?+
The fault codes explained in plain English, the most likely causes, and the exact checks to run in the right order, so whoever is at the car walks up with a plan instead of a guess. The hands-on work still happens at the vehicle; what we remove is the blind guess and the wrong part fitted on a hunch. All online, from £20, and if we can't help, you don't pay.
I don't have an OBD-II scanner, can I still use this?+
You'll need the fault code(s) pulled at least once, most parts stores and many chain garages will read them for free. Prefer to do it yourself? Our Bluetooth OBD-II scanner plugs into your car and reads the codes to your phone. Once you have the codes, send them over along with what the car is doing.
Am I getting an automated report, or a real person?+
A real one. Every request is read and answered personally by a professional mechanic, we don't run your codes through an automated generator. The reply reflects actual reasoning about your codes, your symptoms, and your specific car.
Does this replace an in-person diagnosis?+
Not always, some faults need a hand on the car (a scope, a multimeter, physical inspection). What you get is a clear starting point: what the codes usually mean, what to check first, and whether it's a DIY-reasonable job or one for a garage.
What should I include for the best answer?+
The fault code(s) exactly as shown, the vehicle year/make/model/engine, when the symptom happens (cold start, under load, at speed...), and anything you've already replaced or checked.
How do I pay, and when do I get contact details?+
Prices are listed with each service level above, £20 for Quick Diagnosis, £40 for Detailed Diagnostic, £50 for a 30-minute Voice Call. Payment goes through our Shopify checkout; direct contact details are shared once you go ahead with a service.
What if my code isn't listed in your examples?+
The examples on this page are just illustrations of the format, send whatever code your scanner actually shows, P-, B-, C-, or U- prefixed, and we'll work from that.
How does call booking work?+
We take one 30-minute Voice Call per hour, Monday–Friday, 11:00–20:00, deliberately covering after-work hours like 5–6pm, when most DIY jobs actually happen. Pick a preferred hour when you request one and we'll confirm the exact slot by email, since it may already be taken. The rest of each hour goes straight into Quick Diagnosis and Detailed Diagnostic replies, which is also why those don't need a booked slot at all.