OBD-II diagnostic trouble code
P0604Caution

Internal Control Module Random Access Memory Error

A fault in the ECU's working memory, most often triggered by the same voltage instability that causes other internal control module codes.

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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 P0604?

You can usually keep driving with P0604, 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 P0604?

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

What causes P0604?

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