P0172 Fault Code

System Too Rich (Bank 2)

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0172 code indicates that the engine control module (ECM) has detected a rich fuel mixture in Bank 2 of the engine. This means that there is too much fuel being injected compared to the amount of air, leading to an imbalance in the air-fuel mixture. This can cause increased emissions and reduced engine performance.

What are the symptoms of the P0172 code?

• Rough idling or stalling when the engine is at low speeds.
• Poor acceleration or sluggish performance while driving.
• Decreased fuel efficiency, leading to excessive fuel consumption.
• A strong smell of fuel from the exhaust.
• Emissions test failure due to excessive hydrocarbons.

What causes the P0172 code?

• Faulty fuel injectors that could be leaking or stuck open.
• A malfunctioning fuel pressure regulator that allows too much fuel pressure.
• Defective mass airflow sensor (MAF) providing incorrect readings.
• Dirty or clogged air filters restricting airflow.
• Vacuum leaks in hoses affecting the air-fuel mixture.
• Faulty oxygen sensors that fail to provide accurate feedback to the ECM.

How to fix P0172?

• Inspect and clean or replace the mass airflow sensor if malfunctioning.
• Check for vacuum leaks and replace any damaged hoses or gaskets.
• Test the fuel pressure regulator and replace if necessary.
• Replace faulty fuel injectors and clean the fuel system.
• Check and replace faulty oxygen sensors to ensure proper feedback to the ECM.
• Perform an engine tune-up to ensure all components are in working order.