Bmw code p1168

code p1168 refers toclosed loop control, bank 2--inoperative===causes--wiring--ho2s, front --ecm
most likely wiring or faulty heated oxygen sensor (HO2S) in bank 2 exhaust manjifold
replacing the sensor may fix the fault

P1051 and P1168 are addressed in a TSB from Nissan, and involve issues with the air fuel sensor on the engine. This may also be triggering the P0300 code if the ECM is not programming fuel properly. I recommend checking with a Nissan dealer to see if the tech service bulletin will cover the issues you're having.

http://ww2.justanswer.com/uploads/baddad1/2009-10-27_185251_NTB04-032a.pdf

P0300 means random misfires, multiple cylinders, and could be due to most anything - fuel, ignition, vacuum leak, bad compression, etc. The other two codes, P1168 and P1051 are specific to the manufacturer of your vehicle. Since you did not provide make, model, or year (or engine size), no valid assessment can be made. Please post another question specifying the make, model, and year of your vehicle, and also provide the symptoms that prompted you to take it to have the codes read (other than the check engine light). Maybe someone familiar with your vehicle can provide some better assistance.

Year/make/model/engine size?? This info needed for diagram

post catalyst fuel trim system correction valve above threshold (bank 1) N62 Engine (4.6/4.8)

The code is for a problem with the O2 sensor bank two sensor one.
That is the sensor before the catalytic converter on the side with cylinder two.
Could be the sensor or a problem with the voltage source for the sensor heater.

p1051 and p1168:

P1051 A/F Sensor Heater (Added 29APR2007)
p1168 A/F Sensor Heater.

A/F Sensor The air fuel ratio (A/F) sensor like the oxygen sensor is used by the powertrain control module to measure the amount of oxygen in the exhaust. The PCM uses this data to control the air fuel mixture in the engine. The (A/F) sensor can meter fuel more accurately than an oxygen sensor. The A/F sensor changes current output by measuring the amount of oxygen in the exhaust. The A/F sensor operates at a much higher temperature than an oxygen sensor. The PCM measures the amount of current that is output by the A/F sensor and converts this current flow data to a voltage signal. When the mixture is lean and the oxygen content is high the voltage signal will be above 3.3V. When the mixture is rich and the oxygen content is low the voltage signal will be below 3.3V. When the mixture is at 14.7 to 1 the voltage signal will be at 3.3V. The heater circuit in the A/F sensor shortens the time required for the sensor to reach operating temperature and provides a more accurate signal.
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The A/F error is like an Oxygen Sensor error. There could be a problem with this sensor or the wiring to it causing voltages to be out of specifications.

P0151 Front O2 Sensor, Bank 2 Lean Shift Monitoring,P1168 Closed Loop, Bank 2 i would do the o2 sensor on this side..and thats it unless you get something else

there is a emission system recall for these codes for your year and model contact the Nissan dealer, it is a no charge repair.
here is the summary of that recall

MALFUNCTION INDICATOR LAMP ON WITH DIAGNOSTIC TROUBLE CODE P0300-P0306, P1273 OR P1283. *TT *SC
Make : NISSAN Model : QUEST Year : 2004
Manufacturer : NISSAN NORTH AMERICA, INC.
Service Bulletin Number : 04028A Date of Bulletin : MAR 24, 2004
NHTSA Item Number : 10005976
Component : ELECTRICAL SYSTEM
Summary :
MALFUNCTION INDICATOR LAMP ON WITH DIAGNOSTIC TROUBLE CODE P1031, P1051, P1148, P1168 (A/F SENSOR HEATER / CLOSED LOOP) ON 5 SPEED AUTOMATIC TRANSMISSIONS ONLY. (THIS VERSION SUPERSEDES NTB04-028.) *TT

P1168 is : Closed Loop Control (bank2)