P2191 Fault Code

System Too Lean at Higher Load Bank 1

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

The P2191 fault code indicates that the engine control module (ECM) has detected a lean air-fuel mixture in Bank 1 during high load conditions. This means that there is not enough fuel being delivered to the engine compared to the amount of air entering the combustion chamber. A lean mixture can lead to poor engine performance, higher exhaust emissions, and potential engine damage if not addressed.

What are the symptoms of the P2191 code?

Drivers may notice the following symptoms when this code is triggered:

• Rough idle or stalling during engine operation.
• Decreased engine performance, especially during acceleration or under load.
• Increased fuel consumption as the engine compensates for the lean condition.
• Check Engine Light (CEL) illuminated on the dashboard.

What causes the P2191 code?

Several factors can trigger this fault code, including:

• Insufficient fuel supply due to a clogged fuel filter or failing fuel pump.
• Vacuum leaks in the intake system, allowing excess air to enter.
• Malfunctioning oxygen sensors that provide incorrect readings to the ECM.
• Faulty mass airflow sensor (MAF) causing incorrect air intake measurements.
• Fuel injectors that are dirty or not functioning correctly.

How to fix P2191?

To resolve the P2191 fault code, you can take the following steps:

• Inspect and replace the fuel filter if it is clogged.
• Test the fuel pump to ensure it is delivering the correct amount of fuel.
• Check for vacuum leaks in hoses and connections, and repair any found.
• Replace faulty oxygen sensors or clean MAF sensors as necessary.
• Clean or replace fuel injectors if they show signs of blockage or malfunction.