Practical tips
Practical tips: 16 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.
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