«No answer» is not «no faults»
The difference between silence and a clean memory is expensive. Most cheap scanners do not tell the two apart.
When the app polls the car, every module can answer in three ways: «no faults», «here are the faults», and — nothing at all. The third case is the nastiest, because it looks like the first one.
Why a module stays silent
- It is not fitted to this trim level: looking for a suspension module in a car without air suspension makes no sense.
- It is there, but does not answer over this protocol.
- It is there and answers, but the adapter did not deliver the request.
- It is faulty or has no power — and that is exactly what you want to know.
What CarScan shows
The app polls every module and draws a list: who answered and who kept quiet. A silent module is marked separately and is never counted as «checked».
A scanner that paints a green tick over silence is worse than no scanner at all: the driver leaves confident that everything is fine, while half the car was never asked.
In the report for the mechanic, silent modules are listed separately. That is enough for the mechanic to know where to look at the wiring.
