System Too Lean at Idle (Bank 2)
What it means
This code is the same as P2187 but on bank 2, the side of a V engine that does not contain cylinder 1. The engine computer has found that this bank runs lean at idle despite adding as much fuel as it can, and the most common cause is an air leak near that side.
Related lights
Dashboard lights that may come on with this code.
Symptoms4
- Check engine light on.
- Unstable idle or shaking at a stop.
- Sometimes a hissing sound from the intake manifold area.
- Occasional stalling at a stop.
Possible causes5
- Air leak at the bank 2 side of the intake manifold gasket or from nearby vacuum hoses.
- Leak at the PCV valve or its hose.
- Bank 2 exhaust manifold leak ahead of the upstream oxygen sensor.
- Dirty bank 2 injectors.
- A shared cause such as a dirty MAF sensor or low fuel pressure if P2187 is also stored.
How to diagnose5
- Read all stored codes; P2187 alongside it suggests a shared cause, while P2189 alone suggests a leak on the bank 2 side.
- Compare fuel trims between the two banks at idle.
- Have a smoke test done, focusing on the bank 2 side of the intake manifold gasket.
- Inspect the bank 2 exhaust manifold for leaks ahead of the sensor.
- Check the PCV valve and its hose.
How to fix5
- Replace the leaking hose or gasket.
- Replace the PCV valve or its hose if cracked.
- Repair the bank 2 exhaust manifold leak.
- Clean the bank 2 injectors or replace any faulty one.
- Clear the codes and confirm the trims of both banks are close and back to normal.
Repair cost
In Saudi riyals; the highlighted part is the expected range for this fault.
In the Saudi market: SAR 100–1,200 (≈ USD 27–320)
Our prices come from the Saudi market, converted at a fixed rate (SAR 3.75 per USD). Prices in your country may differ a lot, so we show the cost level.
The cost is low for a vacuum hose, and rises when the leak is at the intake manifold gasket or an exhaust manifold that is hard to reach.
Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026
Frequently asked questions
Why does the code appear on bank 2 only?
Because the cause is usually close to that side, such as a leak in the intake manifold gasket or exhaust for the bank 2 cylinders.
What does it mean if P2187 and P2189 appear together?
It means the cause is shared by both banks, such as an air leak in a common part of the intake, a dirty MAF sensor or low fuel pressure.
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