Definition of the P0174 code
System too poor (Bank 2)
What does code P0174 mean
The P0174 code indicates that there is a lean condition detected by the engine control module (ECM). A lean condition occurs when there is too much air in the air/fuel ratio (AFR) and not enough fuel. The ECM is designed with the ability to adjust the lean condition back to normal, but only by small to medium amounts. If the air-fuel ratio requires more compensation to return to normal than the ECU is capable of, a P0174 code may appear.
What causes the P0174 code?
- Air leakage behind the mass airflow (MAF) sensor, such as a cracked intake cover or damaged intake manifold gaskets.
- Contaminated or damaged mass airflow sensor.
- Defective oxygen sensor
- Incorrect fuel pressure
- Positive crankcase ventilation valve (PCV) leaking
- Exhaust gas recirculation (EGR) port clogged
- Leaks in the brake booster system
What are the symptoms of the P0174 code?
- Increased fuel consumption
- Check engine light comes on
- High or irregular idle speed
- Reduced acceleration
- Engine stutters
How does a mechanic diagnose code P0174?
- Perform a fuel pressure check
- Check the intake system and vacuum lines for leaks
- Check valve cover for worn hoses or leaks
- Check the PCV valve
- Check the air mass sensor with a scan tool or a multimeter
- Check the corresponding oxygen sensor with a scan tool or a multimeter.
The most common errors when diagnosing the P0174 code.
- Replacing a component without first determining its damage through testing
- Failure to check the intake system for cracks or leaks
How serious is code P0174?
In general, the thinning is not that serious. However, note that there is a possibility that the thinning condition is caused by a leak in the intake system. Air intake leaks can allow particles to enter the engine, which can be harmful.
What fixes can repair a P0174 code?
- Air mass flow sensor replacement
- Cleaning the Air Mass Flow Sensor
- Replacing the defective oxygen sensor
- PCV valve replacement
- Vacuum line replacement
- EGR valve replacement
- Brake booster replacement
- Valve cover gasket replacement
Additional notes for catalog number P0174
Make sure the intake manifold and vacuum lines are tight.
