OBD-II diagnostic trouble code
P0172Caution

System Too Rich (Bank 1)

The engine is burning more fuel than it should relative to the air it's taking in on bank 1, which wastes fuel and can eventually foul spark plugs or damage the catalytic converter.

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Code names are compiled from open/standardized SAE and ISO references. Explanations, symptoms, causes and fixes are original. Covers generic (P0/C0/B0/U0) codes only — manufacturer-specific codes are planned for a future update.

Frequently asked questions

Can I drive with P0172?

You can usually keep driving with P0172, but don't put it off — the underlying cause can get worse or lead to further damage the longer it goes unaddressed. Get it diagnosed as soon as you reasonably can.

How much does it cost to fix P0172?

The cost varies too much by cause and vehicle to give a single figure here — a diagnosis will narrow it down.

What causes P0172?

AS
Reviewed by Artyom SemenovAutomotive Editor · Fact-checked by Yauheni Kapliarchuk, Editor-in-Chief
Code names compiled from open SAE/ISO references; explanations and repair guidance are original editorial content
Last verified: 09 Jul 2026 · Our methodology