How this differs from a dealer scanner
The honest answer: by a lot. Here is what any car gives, what depends on the make, and when only a dealer tool will do.
The comparison is inevitable, and staying silent about it only means the driver finds out the difference later and feels cheated. So, in order.
What any OBD-II scanner reads
This is the mandatory minimum and it is the same on every car since 2001:
- engine and gearbox fault codes, active and stored;
- live data — engine speed, temperature, load, trims, oxygen sensors;
- the freeze frame — the conditions under which the code was stored;
- readiness monitors — what the inspection looks at;
- the VIN.
That is enough to understand what happened and to avoid paying for a diagnosis where the answer is visible in two minutes.
What depends on the make
Service routines. A service interval reset does not work on every car or with every adapter.
Manufacturer codes. The letters B, C and U (body, chassis, network) mean different things on different makes. We say honestly «we do not have this code» rather than inventing a meaning.
Modules beyond the engine. Airbags, ABS and climate answer on manufacturer protocols an ordinary ELM327 usually cannot reach.
What we do not have and will not
- Module programming and adaptations. That is a dealer tool and a different kind of responsibility.
- Key coding.
- Anything involving airbags.
When to go to a dealer
If the fault is in a module OBD-II cannot reach; if a module has to be replaced or coded; if the code is manufacturer-specific and only they know its meaning.
When a dealer is not needed
If the Check Engine lamp is on and you need to know how urgent it is. If the engine stumbles, the idle hunts or consumption has risen — the live data answers that by itself. If you are checking a car before buying it, ten minutes and an adapter say more than a visual inspection.
In short
A dealer scanner is a repair tool. Ours is an understanding tool. The first is needed less often than people think; the second, almost always before it.
