Practical tips
Practical tips: 17 pieces on carscan.app — what it means, what to look at in the live data and where to start. Open and free, no app needed.
CarScan and other scanner apps: what is actually different
There are plenty of OBD-II apps, and some have millions of installs and years of history. Honestly about what they do well, and what we chose to do di
14 September 20263 min
Check Engine never comes on: P0650 and buying a car
This takes ten seconds and should be done before buying a car: turn the key without starting. If the Check Engine light did not come on with the other
6 September 20264 min
Charging and voltage: P0560, P0561, P0620, P0621, P0622
The car starts every other time, the battery lamp flickers, and the list shows voltage and alternator codes. Here is how to tell a dead battery from a
6 September 20264 min
Fan, A/C and fuel pump relays: P0480, P0645, P0691
The fan runs non-stop, the air conditioning stopped switching on, or the car will not start — and the list shows relay codes. Almost always this is a
6 September 20264 min
Diagnosing a diesel: how it differs from petrol
A diesel has its own codes, its own live data and its own order of checks. Half the familiar petrol habits simply do not apply.
5 September 20264 min
Fault codes after an LPG conversion: what they mean
Fitted LPG and the light came on. Usually the engine is not broken — the two systems are not agreeing. Which codes are expected and which are not.
5 September 20264 min
Selling a car: what a buyer will see with a scanner
The buyer will turn up with a cheap adapter. Better to know in advance what they will see — and why clearing codes before a sale is pointless.
5 September 20264 min
A fault that only appears in frost or in rain
A fault that comes with the weather is not a mystery but a hint. It names the place to look.
5 September 20264 min
The fault came back after the repair: why, and what to do
The part was replaced, the code cleared, and a week later the light is on again. Five causes in order of frequency, and how to tell them apart.
5 September 20264 min
What the letters and digits in a fault code mean
P0171, C0035, U0100 — five characters, and each says something. Once you can read them, an unfamiliar code makes sense without a reference.
5 September 20264 min
A code that is active, stored or pending
Three words next to the code. They decide whether to go to a garage today or simply keep an eye on it.
5 September 20263 min
The alternator or the battery: telling them apart
The car would not start this morning. Three voltage readings say which one to replace — and they cost nothing.
5 September 20262 min
Leaving the adapter plugged in: what it costs
Unplugging it every time is a nuisance. But an adapter left in the socket can flatten the battery over a week of standing.
5 September 20263 min
Fuel trims: how to read them
Two numbers that show what the unit thinks of the mixture. They find an air leak before the lamp comes on.
5 September 20263 min
The freeze frame: half a diagnosis in one table
Along with the code the car stores the conditions it was recorded under. That is what tells a one-off from a permanent fault.
5 September 20262 min
Clearing a fault code: what "erase" actually does
The button turns the lamp off; it does not fix the car. And it erases exactly what the mechanic needed.
4 September 20263 min
«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.
2 September 20262 min