Code result
P0504
Brake Switch \"A\"/\"B\" Correlation
Moderate severity
What it means
Modern vehicles use two redundant brake switch signals (often one normally-open and one normally-closed). When the two signals disagree, this code is set; common causes include a misadjusted switch, internal switch failure, or wiring fault.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Brake switch misadjusted
highOne of the most commonly reported causes for this code — check this first.
Brake switch internal fault
mediumA plausible cause — test and verify before replacing parts.
Related help
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