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All codes/P2189

P2189

System Too Lean at Idle (Bank 2)

Moderate severity

This code means the engine's computer has detected that the air-fuel mixture is too lean (too much air, not enough fuel) specifically when the engine is idling on the second bank of cylinders. This typically points to unmetered air entering the engine or an issue with fuel delivery.

System Too Lean at Idle (Bank 2)

Common causes

  • Vacuum Leaks

    Cracked or disconnected vacuum hoses, intake manifold gaskets, or PCV system components can allow unmetered air into the engine.

    high

    Typical part cost: $0-200 repair

  • Faulty PCV Valve/System

    A stuck-open PCV valve or a leak in its hose can create a vacuum leak, especially at idle.

    medium

    Typical part cost: $20-100 part

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First things to check

  1. 1Listen for vacuum leaks and visually inspect all vacuum hoses, intake manifold gaskets, and PCV system components.
  2. 2Perform a smoke test on the intake system to pinpoint vacuum leaks.

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Tools you may need

Already have a compatible scanner? Use it. If not, a Bluetooth OBD2 adapter can help you confirm engine codes and check supported live sensor data before replacing parts.

Illustration of a Bluetooth OBD2 adapter, not a product photo

Basic checks

Veepeak OBDCheck BLE

A Bluetooth LE adapter for reading standard engine codes and supported live data.

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Illustration of a Bluetooth OBD2 adapter, not a product photo

Regular diagnostics

vgate iCar Pro BLE 4.0

A Bluetooth LE adapter with an automatic sleep feature for routine code and sensor checks.

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Illustration of a Bluetooth OBD2 adapter, not a product photo

Another option

OBDLink CX

A Bluetooth LE adapter to consider when comparing supported vehicles and diagnostic apps.

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Illustrations shown, not product photos. Check vehicle, phone and app compatibility before buying. These adapters do not guarantee access to ABS, airbags or manufacturer-specific systems. Clearing a code does not repair the fault and can reset emissions readiness monitors.

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Related codes

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Frequently asked questions

What is the difference between P2187 and P2189?

P2187 refers to a lean condition on Bank 1 (the side of the engine with cylinder #1), while P2189 refers to a lean condition on Bank 2 (the opposite side). If both appear, it often points to a common issue like a MAF sensor or a large vacuum leak.

Can a dirty air filter cause P2189?

A very dirty air filter can restrict airflow, potentially causing a rich condition, not typically a lean one. However, if the MAF sensor is dirty due to a poor filter, it could cause misreadings leading to a lean condition.

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