Avensis error conditions

[spireman]

I have an Avensis 2005 petrol automatic. For the past two years it has been ticking over slowly and intermittently stalling as I set off. The main dealer said it may be the fuel injectors and to replace them would be £500 and it may not solve the problem. Now I have an engine warning light and on investigation have three faults. 1,  System too lean Bank 2.  2, H025 heater control circuit Low bank 1 sensor2 and 3, knock Server 1 circuit high bank1 or single sensor.    Could these all be related to a single fault?  I was very low on oil recently and the engine got very hot but the car is now driving better than ever.  I don't want to lay out hundreds of pounds for something that may just need cleaning.  Any advice welcome.

 

[FROSTYBALLS]

Moved to the Avensis club.

[Konrad C]

I think the fault is with your O2 sensors, and may be have been part of the original problem. You don't say what engine in your car but it is either 1.8 1ZZ or 2.0 AZ. These engines are totally different, and the major difference is that the 2.0l is direct injection. Maybe you can add the engine size to your cars description. I think it may be the 2.0l, because you mention bank 2 sensor 2. There are 4 O2 sensors on the 2.0l but less on the 1.8l engine. 

If I had a running problem, before carrying out any fixes, check what all the components are doing by carrying out a live diagnostics. Then you can see what is going on. Most of the components you have mentioned are covered by diagnostics. Then individual checks can be done, like measuring the resistance outputs of the O2 sensors. 
How did the dealer come to the conclusion of the injectors, and did they check the other parts before replacing the injectors?
The big question, is how many miles the car has done, and what is the service history of the car? You have to factor in wear and tear!

Try disconnecting the Battery for about a minute to see it resets the ECU back to learning mode, then drive the car at various engine speeds and loads.  

[spireman]

Konrad C thanks for your reply. You are right that my car is a 2ltr and it has done 109000 Miles.  I asked my local garage to tat the car and they said it showed 8 faults so the ams may be faulty.  I now have only one fault showing and that is the H025 Heater control circuit low bank 1 sensor2. If I reset the warning light it stays off for about 13 hours then comes back again.