I HAVE A CHEVY Z71 4X4. AND THE INSPECTION FAULT CODE IS P0151. WHAT IS THE PROBLEM

Question edited for clarity. It is P-Zero 0, not P-oh O.
Please always include 'year make model' first 3 words, or it it is difficult to answer and some vehicles are slightly different or more precise and will show known issues.

P0174 - OBD-II Trouble Code Fuel System Too Lean (Bank 2)

https://repairpal.com > obd-ii-code-p0174
When a vehicle has the fault code P0174, it means that computer can no longer automatically adjust the mixture between air and fuel. Code P0174 applies to V ...

P0174 OBD-II Trouble Code: System Too Lean (Bank 2)

https://www.yourmechanic.com > Articles
Code P0174 indicates that there is a lean condition detected by the Engine Control Module (ECM). A lean condition will be created if there is too much air, and ...

P0151 Code - What Does It Mean & How To Fix It - OBD2PROS

https://obd2pros.com > dtc-codes > p0151
A P0151 code is caused by an ECM (Engine Control Module) receiving a signal indicating the O2 sensor for bank 2 sensor 1 has failed to increase the voltage ...

Code P0171 - System Too Lean: Symptoms, causes, common ...

https://www.samarins.com > diagnose > p0171
Jul 10, 2021 - The OBDII trouble code P0171 - System Too Lean (Bank 1) means that the engine air-fuel mixture is too lean, or there is too much air and too ...

Generic obd 2 system allows access only to systems that affect exhaust emissions and dealer level software is needed for everything else. A fault that affects the exhaust emissions should switch on the engine check light and store a fault code in the memory. While the light is on the engine is operating on the get-you-home programme.

When there is a problem, after a thorough visual inspection and ensuring the routine maintenance is up to date, a code reader or scanner is used to read stored fault codes, examine live data and suchlike.
The fault code is an invaluable start point in the diagnostic process and repair, but in order to advise you further you need to tell us what the code is...

both are o2 sensor problems and should be related to each other p0151 -o2 senson malfunction bank 2 sensor 1[ which would be the sensor on the no.2 cylinder side ---before the cat conveter --the p1153 o2 bank 2 sensor1 insuffent switching --its the same o2 sensor -check the wiring and connection if good- than replacement of the o2 sensor is dvised

Do you have a check engine light on? Have you done an engine control module fault code test (OBD2 control system), is fuel pressure OK under a load? Has the fuel injector spider manifold (inside the throttle bore) assembly been replaced, that is a known problem.

We guess DTC P0151... essentially the same as P0136 and P0137 and P0131, a P0151 code refers to the first oxygen sensor on Bank 2 . P0151 means the O2 oxygen sensor's voltage remained low for longer than 2 minutes. This, is interpreted by the ECM as a low voltage condition and sets the MIL. Bank 2 Sensor 1 is located in front of the catalytic converter.

There may be no visible symptoms to the driver, other than the MIL (Check Engine / Service Engine Soon) illumination.

A code P0151 may mean that one or more of the following has happened:
Faulty o2 oxygen sensor
Short to voltage on O2 signal circuit
High resistance or open on O2 signal circuit

Possible Solutions:
Replace faulty sensor
Repair short, open, or high resistance on o2 signal circuit

code p2189 and p2187 = air/fuel mixture too lean on both cylinder banks which in turn generates excessive emissions = failed inspection.
What can cause a lean mixture:
- Incorrect main charge signal
- Intake air system leaking
- Fuel pressure too low
- Volume supply of fuel pump too low
- Mechanical fault in injectors
- PCV valve leaks
- Leaks in exhaust system
- EVAP canister purge valve mechanically faulty (hangs open)
All these must be checked.

P0151 code is from a low voltage from the oxygen sensor circuit. P0300 code is a result from an engine misfire in one of the cylinders. The 4WD in the information center and the two Error Codes sound like an electrical problem.

Hi, a P0446 means Evaporative Emission Control System Vent Control Circuit Malfunction

Full details @ http://www.obd-codes.com/p0446

code po300 is a random misfire code do a tune up plugs, wires etc and clear the code it should be fine

try cleaning the throttle plate with the right cleaner . from a auto parts store.