OBD2 Live Data: What to Watch and What Is Noise
Modern cars report dozens of live parameters and most of them will not help you. The handful that actually diagnose faults, and how to read them together.
AutoScan journal
Fault codes explained properly, what each one usually costs to put right, and how to check it yourself before anyone quotes you.
Modern cars report dozens of live parameters and most of them will not help you. The handful that actually diagnose faults, and how to read them together.
Why the EGR system exists, how the ECU works out that too little exhaust gas is getting through, and when cleaning the valve is worth doing instead of replacing it.
The dates that decide whether a car supports OBD2 diagnostics at all, what generic OBD2 can and cannot reach, and how to check your own vehicle in two minutes.
Why the pre-cat lambda sensor circuit matters more than the one behind it, how to tell a dead sensor from bad wiring, and what the repair usually costs in the UK.
The UK MOT does not read readiness monitors, but they are still the best proof that a repair actually worked. Here is what they are and how to get them to complete.
What a small evaporative emission leak really is, why it hides so well, the cheap causes to rule out first, and how a smoke test finds it properly.
Short-term and long-term fuel trim tell you whether the engine is running rich or lean and roughly why. How to read them, and what the pattern across engine load reveals.
How to tell a genuinely dead mass air flow sensor from one reading low because of a restriction, a split pipe, an oiled filter or a wiring fault, plus real costs.
Where AutoScan fits among free apps, brand-specific tools and handheld scanners, including a straight section on when you should buy something else instead.
A large evaporative leak is the one EVAP fault you can often find yourself in five minutes, and the fuel cap is behind it more often than anything else.