Your Diagnostic Buddy

Faster diagnostics.
Without replacing the mechanic.

Hold the Light surfaces the right information at the right moment, so the technician stays the one who decides. Investigate faults by code, symptom or description — and always get the next logical step.

  • Less time lost searching
  • Fewer parts replaced for nothing
  • OBD optional — works with no hardware
  • An interface built for the workshop
ACTIVE INVESTIGATION
VW Passat 2.0 TDI — 168,400 km
Search

P0299 + “power loss uphill”

Suggested next step

High payoff

Check the condition of the boost pipes.

Probability
88%
Time
4 min
Effort
Low

Other paths

Turbo actuator74% · 18 min
MAP sensor61% · 6 min
MAF sensor42% · 5 min

The app suggests. The technician chooses. The app reorganises the investigation.

The app suggests.The technician chooses.The app adapts.Never the other way around.

How it works

Hold the light. Never do the job for you.

Hold the Light organises information, finds relationships between symptoms and codes, and follows the investigation from start to finish.

Identify the vehicle

By VIN, plate, manual selection or optional OBD link. The investigation starts in seconds.

One single search box

Type whatever you want — P0299, “white smoke”, “won't start when hot”. The app interprets and cross-references sources.

Next Best Step™

It combines probability, time and effort to suggest the check with the highest diagnostic payoff.

You decide

Pick another path, go back, ask for a different explanation. The investigation reorganises itself, no judgement.

Diagnostic Payoff Engine

It isn't just probability. It's payoff.

The algorithm weighs probability, time, ease and diagnostic value. The goal is simple: maximum progress, minimum effort.

  • A 20% hypothesis you can confirm in 30 seconds may come first — ruling it out costs nothing.
  • A 90% hypothesis that is quick to verify is almost always the top priority.
  • If you choose another path, the app replies “let's investigate that path” — and reorganises everything.

Example — suggested ordering

1Hypothesis A
90% · 6 min
2Hypothesis B
70% · 3 min
3Hypothesis C
88% · 45 min

The chosen one offers the best balance between high probability and speed.

Features

Everything you need. Nothing you don't.

Fault code library

Every code with meaning, causes, symptoms, tests, fixes and similar cases — organised, not buried in text.

Universal search

One single box. Codes, symptoms, descriptions, combinations. The app interprets what you type.

Investigation timeline

Every test run, every result, every change of hypothesis is logged. You never lose the thread.

Optional OBD

DTCs, live data, active tests, regenerations — whenever you want. The app also works with no hardware at all.

Real cases and filtered videos

The app doesn't dump 30 videos on you. It picks the ones that best explain, show and solve.

Infinite explanation

If it doesn't click, the app explains it another way — text, diagram, video, example. Never "already explained".

Pricing

Simple. As it should be.

Start free. Move to Pro when you need it. Scale to the whole workshop when it makes sense.

Free

To try the app with one vehicle per day.

€0forever
  • 1 new investigation per day
  • Universal search
  • Fault code library
  • Basic Next Best Step™
Most popular

Pro

Unlimited use for individual technicians.

€25per month
  • Unlimited investigations
  • Full history
  • Integrated optional OBD
  • Infinite explanation
  • One active session at a time

Workshop

For workshops — run the daily flow and share knowledge.

€500per month
  • Multi-mechanic users
  • Shared cases and investigations
  • Daily workshop flow management
  • Shared team history
  • Priority support

Individual accounts allow only one active device at a time. A new sign-in automatically ends the previous session.

FAQ

Frequently asked questions

Does Hold the Light tell me what to do?+

No. The app suggests. The technician chooses. Then it adapts to the technician's decision — never the other way around.

Do I need an OBD scanner?+

No. The app works fully without any hardware. If you connect an OBD adapter, extra features become available such as DTCs, live data, active tests and regenerations.

How does Next Best Step™ work?+

It's the engine that ranks hypotheses by combining probability, time, effort and diagnostic value. The goal is the check with the highest payoff — not simply the most likely cause.

Can I switch hypothesis midway?+

Always. You can go back, explore another component, return. The investigation reorganises automatically. The app never blocks a path, except in safety-critical situations.