OBD-II diagnostic trouble code
P0115Caution

Engine Coolant Temperature Circuit Malfunction

The coolant temperature sensor circuit is not producing a usable signal, which can make the engine run in an overly rich, cold-start-style fuel mode indefinitely.

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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 P0115?

You can usually keep driving with P0115, 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 P0115?

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

What causes P0115?

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