The description of fault code P0174 is ‘System Too Lean Bank 2’. This code indicates that an engine lean condition has been detected by the Engine Control Module. Lean engines are caused by too much air and not enough fuel. The vehicle computer can correct the mixture in such situations. It can only correct this to a certain extent. The P0174 error code is set if the phase difference between the two phases is too large and the ECU can’t restore the normal air-fuel ratio. P0171 is a similar code.
Table of Contents
What are the causes of fault code P0174?
- Air leakage after the mass flow sensor (MAF), such as a torn manifold or hose.
- Faulty Oxygen Sensor
- Fuel filter clogged
- Incorrect fuel pressure
- Faulty fuel pump
- Leakage from the crankcase ventilation valve
- Exhaust Gas Recirculation (EGR) clogged
- Leaking brake service
- Fuel pressure regulator malfunction (usually occurs with rich mixtures, but should be checked).
Note: If you use oily air filters, the MAF can become dirty.
What are the symptoms of fault code P0174?
- Fuel consumption increases
- Engine fault light is illuminated
- Rough or High Idle
- Engine power loss when accelerating
- Misfiring engine
- Engine stalling
How to Fix Fault Code P0174?
- Check for leaks in the intake system and vacuum line
- Check the valve cover for leaks and worn hoses
- Check the PCV valve
- Test the mass airflow sensor
- The oxygen sensor must be tested
Then, according to the situation;
- Replace the mass flow sensor after cleaning the sensor
- Replace the oxygen sensor if it is faulty
- Replace the PCV valve
- Replace the vacuum line
- Replace the EGR valve
- Replacement brake servo
- Replacement the valve cover gasket
Check for leaks in the intake manifolds and vacuum lines.
P0174 Fault Code: Is it Important?
Nitrogen oxides (NOx) are released by vehicles that run on lean mixtures. These NOx can be harmful to your health and cause respiratory issues such as asthma. This can cause damage to the catalytic convertor, which could lead to long-term damages of your vehicle’s interior components. Air intake leaks can let particles into the engine that could damage it.
