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P2187 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


Currently, the P2187 OBD-II code indicates that the computer on-board detected a fuel mixture from the test was lean and it’s at idle either in Bank 1 or Bank 2 of the engine (the side with the corresponding cylinder number). Lean fuel mixtures are those that contain a lot of air and little fuel.


The P2187 trouble code indicates that there is an issue with the fuel mixture in the vehicle.


P2187 OBD-II trouble codes can be caused by two broad categories of things. Some part of the fuel system is allowing air into it, or it is restricting the flow of fuel. This non-ideal fuel mixture is detected by the Engine Control Module (ECM) and the Check Engine Light is illuminated on the dashboard of the vehicle.


Other symptoms may be present after the P2187 code illuminates the Check Engine Light, including:

  • Starting out is difficult
  • The smell of fuel
  • Idle or missing frequently
  • Noises of whistling


When a mechanic diagnoses a P2187 fault code, they start by using a specialized scan tool that establishes a wireless connection to the vehicle’s on-board computer, scans the vehicle’s various systems, and reports any anomalies. Test drives are also recommended. The mechanic is able to determine the possible cause of lean fuel mixtures indicated by the P2187 code by consulting professional repair manuals or by searching for any other trouble codes present on the computer screen. There will be a visual and hands-on examination of the fuel system and related components.

In addition to finding a leak, blockage, or faulty component, the mechanic will check for the intake manifold receives additional air and low fuel pressure. Once these problems have been diagnosed, the technician will proceed to repair them or replace them. To ensure the issue has been satisfactorily resolved, the mechanic runs a diagnostic scan again and tests drives the vehicle to clear the code.

Common mistakes

It is important for mechanics not to make the following mistakes when troubleshooting the P2187 code:

  • Leaving trouble codes on after repairs are performed
  • Not verifying the P2187 code’s existence

How serious is this?

There is still the possibility to drive a vehicle registering the P2187 code, but it is important that the underlying issues are addressed as soon as possible. Fuel mixtures incorrectly run can wear out other systems and components, incurring greater costs and frustration than addressing the problem as soon as it appears.

What repairs can fix the code?

The following repair(s) may need to be performed after a mechanic validates the P2187 fault code:

  • Replacing hoses that leak, such as EVAP hoses or vacuum hoses
  • Inspecting the exhaust system for leaks and repairing them
  • Fuel filters, fuel pumps, or fuel pressure regulators need replacing
  • Replacing the caps on gas and oil filler pumps
  • Changing the oxygen, mass airflow, or MAP sensors

Related codes

None listed.


If you see this code, it is important to address the problem as soon as possible. This is typically caused by a lean fuel mixture, which would cause the car to not run properly without being fixed. You may still be able to drive your vehicle, but it is important to address the underlying problem as soon as possible.

P2187 Code – What Does It Mean & How To Fix It