A fault code doesn’t yet mean the unit or sensor itself is faulty: often it’s the plug and connector leading to it.
Possible causes
- Air leak: cracked hoses, intake gasket, vacuum hose, PCV valve
- Weak fuel pump or clogged fuel filter
- Dirty injectors
- MAF sensor reads low
What you can do yourself
- Listen at idle: a hissing sound means an air leak.
- Look at the fuel trims on the “Sensors” tab.
- Check the fuel pressure.
Stop and don’t drive on if:
- The Check Engine light is flashing
- The temperature gauge is in the red or the overheating light is on
- The red oil pressure light is on
- Smoke from under the bonnet, a burning or petrol smell
- Strong jerking, knocking from the engine, or the car barely moves
OCases from Oleg’s practice
- Changan 2025 The revs hunt, the engine stalls, code P017100 — lean mixture. The live data points to the fuel system: we recommended checking the high-pressure pump, injectors, filters and fuel pressure. How it went ↗
- Toyota RAV4 2005 The temperature readings jump: too high one moment, dropping sharply the next; codes P0125, P0171, P0420. The coolant temperature sensor was turning in its base — it needs replacing; for P0171 and P0420 a fuel system check is recommended. How it went ↗
On Oleg’s website:Injector cleaning ↗
The explanation comes from the error code reference in the AvtoElektrik PRO app.