What does code P2190 mean?

P2190 means the fuel mixture runs rich specifically at idle on bank 2 — extra fuel arriving when demand is lowest. It’s moderately serious — you can usually keep driving gently, but diagnose it soon.

What does P2190 mean in plain words?

The fuel mixture runs rich specifically at idle on bank 2 — extra fuel arriving when demand is lowest. One bank rich at idle points at that bank's injectors leaking; both banks rich together points at fuel pressure or a purge valve stuck open.

How is this different from P0171/P0172?

Scope: P0171-family means the correction maxed out overall; P2187-family means specifically at idle. The idle-only version usually has a smaller, more findable cause — treat it as a head start.

Why does my idle also surge with this code?

Same root: the computer chasing a mixture it can't balance at low airflow. Fix the lean/rich cause and the surge typically leaves with it.

P2190 — System Too Rich at Idle (Bank 2)

Moderate

Quick answer

P2190 means the fuel mixture runs rich specifically at idle on bank 2 — extra fuel arriving when demand is lowest. First move: one bank rich at idle points at that bank's injectors leaking; both banks rich together points at fuel pressure or a purge valve stuck open.

What it means

P2190 reports that the fuel mixture runs rich specifically at idle on bank 2 — extra fuel arriving when demand is lowest.

These codes are the fuel-trim verdicts scoped to idle only — and that scoping is the diagnostic gift. A mixture problem that exists only at idle is dominated by fixed-quantity causes: a vacuum leak (fixed extra air, huge at idle, diluted at speed) or a leaking injector/purge valve (fixed extra fuel, same math in reverse).

The steps below run cheapest-first — because in this family, the cheap causes really are the common ones.

P2190 symptoms: what you'll notice

A fuel smell at idle, sometimes with black-tinged exhaust.
A rough, loaded-up idle that cleans out when you rev the engine.
Hot restarts that take longer cranking than they should.
City fuel economy slipping while highway mileage stays normal.

Common causes

Ordered from most to least likely.

1.

See the diagnosis steps

This family shares its suspect list; the steps walk it in cost order.
2.

Wiring or connector damage

The universal suspect for circuit-flavored codes.
3.

The component named by the code

Condemned by measurement, never by guess.

How to fix it: diagnosis, step by step

Cheapest and most likely checks first.

1 Confirm the idle-only pattern

Watch long-term fuel trim at idle versus at 2,500 RPM. Big correction at idle that fades with RPM is the fixed-quantity signature this family exists to report.
2 Lean codes: hunt the leak

Intake boot, vacuum hoses, PCV, intake gaskets, purge line — the full hunt is our vacuum leak guide, spray test and all.
3 Rich codes: find the fuel

Pinch the purge line at idle (trims snap back = purge valve), check fuel pressure, and consider a leaking injector — plug reading finds the wet cylinder.

Parts & tools you may need

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Related codes

Frequently asked questions

What does code P2190 mean?: P2190 means the fuel mixture runs rich specifically at idle on bank 2 — extra fuel arriving when demand is lowest. It’s moderately serious — you can usually keep driving gently, but diagnose it soon.
What does P2190 mean in plain words?: The fuel mixture runs rich specifically at idle on bank 2 — extra fuel arriving when demand is lowest. One bank rich at idle points at that bank's injectors leaking; both banks rich together points at fuel pressure or a purge valve stuck open.
How is this different from P0171/P0172?: Scope: P0171-family means the correction maxed out overall; P2187-family means specifically at idle. The idle-only version usually has a smaller, more findable cause — treat it as a head start.
Why does my idle also surge with this code?: Same root: the computer chasing a mixture it can't balance at low airflow. Fix the lean/rich cause and the surge typically leaves with it.