The P0174 code - Definition, Causes, and Symptoms (and How to Fix It)

The trouble code P0174 appears when bank 2's O2 sensor feels the mixture of air and fuel is not correctable.

This could be due to many reasons. The P0174 code is explained in detail below.

Definition of P0174

P0174 – System Too Lean (Bank 2)

What does the P0174 Code refer to?

This code signifies that bank 2's O2 sensor detected a mixture too low to correct. A fuel mixture with a +-15% O2 sensor may be corrected. If corrections are needed outside this range, P0174 codes will be saved.

P0174 Symptoms

P0174 codes are most commonly associated with a check engine lamp and poor engine performance. There may also be hiccups, jerky acceleration and other symptoms.

Here’s the signs of code P0174:

• Check engine light
• Very low Engine Performance
• Rough Idle
• Sensible fuel consumption
• Hiccups in acceleration

What is the severity of the P0174 Code Code?

Medium – It is nothing that is going to destroy other parts of your car immediately if you keep driving with your car.

But, in the long run, it can damage the engine’s internal parts because of the lean mixture. Do not accelerate if you get this code. You should drive carefully to the shop and have the problem fixed immediately.

What causes the P0174 Code?

The P0174 error code could be caused by many things.

P0174 is most commonly caused by a malfunctioning MAF sensor, or an unresolved vacuum leak. Low fuel pressure problems such as a weak or blocked fuel filter can also cause the P0174 code.

Here’s a list of the possible P0174 causes:

How can you fix P0174?

• Replace or clean MAF sensor
• Leakage Repairs
• Replacing the fuel filter
• Change the fuel pump
• Replacing the PCV valve
• Replacing the intake manifold gasket
• Replacing O2 sensor 2

Common diagnostic errors

Common mistake: You replace O2 sensors first, even if you are replacing them on the wrong bank.

Bank 2 – which this trouble code refers to is located on the side with cylinders 2, 4, 6, etc. Find out how to identify banks by reading Bank 1 vs Bank 2.

It is also a mistake to ignore vacuum and intake leaks.

Recommendations for Diagnosis

How do you diagnose the P0174 code?

1. An OBD2 Scanner can be connected to your car and you will see any related codes.
2. Attach an EVAP smoke device and pressurize your system for any vacuum or intake leaks. Reset the codes and repair any vacuum leaks.
3. You can either look for one or visit a shop that does. This greatly aids in diagnosing the problem.
4. Clean the MAF sensor with an electronic cleaner.
5. Reinstall the MAF sensor and clear the error codes. If the problem persists, continue troubleshooting.
6. An OBD2 scanner can check the MAF sensor's values. If something looks suspicious – replace the MAF sensor.
7. For fuel pressure checks on driving or idle, attach a fuel gauge to your fuel rail. If you notice a low fuel pressure – replace the fuel filter or fuel pump.
8. If you have tried everything above and the problem still persists – Check the PCV valve function and the EVAP purge control valve.
9. If you didn’t find any problems with the PCV or EVAP Valve, it is time to replace the O2 sensor on Bank 2.