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P0504 can affect brake-lamp or cruise-control signals

The module detected disagreement between brake-switch inputs that are expected to correlate.

September 25, 20261 min read
AI4Car quick readA short, original guide from the AI4Car knowledge library.

Check brake lamps and scan-tool switch states as the pedal moves. If lamps fail or brake behavior changes, do not continue driving until the issue is inspected.

Quick educational note

For information, not a diagnosis or repair instruction. Vehicle-specific checks are still required. Consult the manufacturer's guidance and a qualified technician.

How to use this information

This article explains general principles and does not establish what is wrong with your vehicle. Read the content limitations.

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P0504 can affect brake-lamp or cruise-control signals | AI4Car