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P2187 OBD-II Trouble Code: System Too Lean at Idle DTC

Check Engine Light

P2187 trouble code definition

The P2187 OBD-II fault code means the vehicle’s on-board computer has detected a lean fuel mixture at an idle in either Bank 1 or Bank 2 (the side of the engine with the corresponding number on the cylinder, if applicable). A lean fuel mixture means there is an excess of air and a shortage of fuel.

What the P2187 code means

The P2187 trouble code means there is an issue with the vehicle that is causing a lean fuel mixture.

What causes the P2187 code?

There are two broad options that can cause the P2187 OBD-II trouble code to register. Either something is allowing air into the fuel system or something is restricting the flow of fuel. The Engine Control Module (ECM) detects this non-ideal fuel mixture and illuminates the Check Engine Light on the vehicle’s dashboard.

What are the symptoms of the P2187 code?

After the P2187 code incites the Check Engine Light to light up, other symptoms may be present, including:

How does a mechanic diagnose the P2187 code?

In diagnosing the P2187 fault code, a qualified mechanic begins by verifying the code with a specialized scan tool that connects to the on-board computer, scans the data from the vehicle’s various systems, and reports any anomalies in the form of codes. A test drive may also be in order. Once the code has been validated, the mechanic may consult professional repair manuals or use the appearance of any other trouble codes to narrow down the potential cause of the lean fuel mixture indicated by the P2187 code. This is followed by a visual, hands-on inspection of the fuel system and related components.

Since the lean fuel mixture is a result of either additional air seeping into the intake manifold or low fuel pressure, the mechanic will systematically go through potential causes of these two problems until the technician locates a leak, blockage, or faulty component to be repaired or replaced. Then, the mechanic clears the code before re-running a diagnostic scan and test driving the vehicle to ensure the issue has been satisfactorily resolved.

Common mistakes when diagnosing the P2187 code

In troubleshooting the P2187 code, mechanic should be leery of making the following common mistakes:

  • Neglecting to clear the trouble code after repairs are made
  • Neglecting to verify the P2187 code’s existence

How serious is the P2187 code?

While it is still possible to drive most vehicles registering the P2187 code, it is important to address the underlying issues at your earliest convenience. Running an improper fuel mixture can affect the integrity of other systems and components, which incurs greater repair costs and frustration than taking care of the problem when it initially appears.

What repairs can fix the P2187 code?

After a certified mechanic validates the P2187 fault code, the following repair(s) may be necessary to resolve the issue:

Additional comments for consideration regarding the P2187 code

As in the diagnosis of any other OBD-II trouble code, the process can take time due to the possible need for multiple tests and inspections. In troubleshooting the P2187 code, however, this length of time can be particularly long due to the long list of potential culprits. The strategy to pinpoint the issue is one of moving down a list, beginning with the most likely cause and working down to less commonly seen causes.

Need help with a P2187 code?

Contact YourMechanic to be connected with a knowledgeable vehicle technician in your area. This technician can even travel to your home or office if needed. Get your quote for the cost of repairs, book a consultation online, or speak with a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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