«Where to start» advice now covers 113 codes

Thirty-nine new write-ups in two batches: sensor circuits, coils, injectors, the fuel pump, boost. In the app and on the site alike.

A fault code says which check failed. It does not say which part to buy — and that is exactly what the driver needs. So every code in the app carries a short «where to start» note: what to check first, what costs nothing, and what not to do.

There are now 113 of them out of 298 — there were 74.

What was added

Sensor circuits — mass air flow, manifold pressure, temperature, oxygen; the ignition coils and injectors per cylinder; the fuel pump, the rail pressure sensor, the knock sensor, boost, the cooling fan relay.

One rule matters more than the rest

Half of the new codes are about the circuit of a sensor, and every note says so plainly: a circuit is the wiring and the connector far more often than the part itself. «Replace the sensor» on such a code sends someone to pay for a healthy part.

So everywhere the free checks come first:

• swap the coil to a neighbouring cylinder and see whether the code follows;
• listen for the fuel pump whirring when the ignition goes on;
• compare the intake air temperature with the weather on a cold car;
• watch whether the oxygen sensor voltage is still swinging.

Each of those takes a minute and halves the list of suspects.

The app and the site say the same thing

The reference on the site is not retyped by hand — it is built from the app sources. Diverging texts would mean reading one thing on the site and seeing another in the app at exactly the moment help is needed.