P2189 Code: System Too Lean at Idle (Bank 2)

Reviewed by

William Guzenski, ASE Certified Master Automobile Technician

Contact Center Manager and Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on August 31st, 2023

Reading Time: 3 minutes
Summary
  • The P2189 code stands for “System too lean at idle,” which means the air-fuel mixture during idle has too much air and not enough fuel.
  • Possible causes of the P2189 code include a faulty oxygen sensor, faulty gas cap seal, and a loose oil filler cap.
  • Decreased engine performance, difficulty starting, and irregular idle are common symptoms of the P2189 code.

If your vehicle has engine-related issues, then using an OBD-II scanner is a great way to diagnose the problem. If a P2189 diagnostic trouble code (DTC) appears in your scan tool, you may be wondering what it means. This article will help you figure out its definition, causes, and symptoms.

What Does the P2189 Code Mean?

The P2189 code means “system too lean at idle.” This means that the air-fuel mixture during idle is lean, which means it has too much air and not enough fuel. This issue can be caused by several faulty components. The powertrain control module (PCM) uses several sensors to determine the right air-fuel ratio to use to keep the engine running efficiently while it’s idling. The PCM triggers the P2189 code when it cannot achieve the desired air-fuel ratio.

The P2189 code may be triggered if the PCM cannot achieve the desired air-fuel ratio.

The P2189 code also indicates that the problem is occurring in the engine’s second bank.

Note: The P2189 code can be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Possible Causes of the P2189 Code?

The P2189 code can be triggered by the following issues:

A clogged fuel filter can cause the P2189 code to be set.

What are the Common Symptoms of the P2189 Code?

Here are some of the most common symptoms of the P2189 code:

  • Decreased engine performance
  • Difficulty starting
  • Irregular idle
  • Whistling noises
  • Lower turbo boost numbers
  • Fuel smell

How to Diagnose the P2189 Code

Identifying the root cause of the P2189 code can be difficult because there are a lot of parts that you need to check. Accessing certain components can be hard if you don’t have the right tools or experience. We recommend consulting a professional if you want to properly diagnose the issue that’s triggering the P2189 code.

Check out this video If you want to learn more about the diagnostic process:

How to Fix the P2189 Code

Unfortunately, there isn’t a single umbrella solution for the P2189 code because each vehicle is designed differently. As a result, the repair process will vary greatly between vehicles. To determine the right repair procedure, you must first get an accurate diagnosis.

Once you’ve figured out the root cause of the P2189 code, you can look up credible online repair resources and how-to guides for possible solutions. Always consult your vehicle’s repair manual when it comes to troubleshooting and repairing diagnostic codes.

Consulting Chilton repair manuals can be useful. ALLDATA subscriptions are even better, as they provide detailed factory repair information for drivers who want to do repairs themselves. But if you aren’t an expert in automotive repair, it might be best to leave it to a professional.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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Published by
CarParts.com Research Team and William Guzenski, ASE Certified Master Automobile Technician