Fault Codes that won't go away

[Dynastone]

A short while ago I purchased a Qashqai 2008 Tekna 2.0 AWD. This car has more faults then you could possibly imagine. Although I am working through them and my savings I cannot cure one of them.

Can anyone help me please!

I have 2 fault codes P2002 & P2a00 which will not go away.

I have installed a new DPF and the sensors either side, all new parts. I have cleaned the EGR valve which was fairly clean to begin with. I have reset the codes each time but after driving a short distance (5 miles or so), then stopping and restarting the 2 codes come back. I have been to a so called diagnostic garage who does not know what is causing this. The by product of these codes is that the engine shakes when under load at speed and also shakes quite a bit on tick over.

Does anyone have any idea what could be causing this problem.

Thank you

Dynastone.

[gvmdaddy]

P2002......Back Pressure Sensor
P2a00......Air Fuel Ratio (A/F) Sensor Bank 1 Sensor 1 Air Fuel Ratio (A/F) Sensor Bank 1 Sensor 1 harness is open or shorted Air Fuel Ratio (A/F) Sensor Bank 1 Sensor 1 circuit poor electrical connection Fuel pressure Fuel injector Intake air leaks

Read more: https://www.engine-codes.com/p2a00_nissan.html

[Dynastone]

Thanks for the reply, I also found this info on the net but did not know how to perform a mixture reset?