Code result
C0399
4WD Mode Switch Circuit Malfunction
Moderate severity
What it means
The transfer case or 4WD control module has detected an invalid signal from the driver-operated 4WD mode selector. Mode requests from the dashboard may be ignored.
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
Mode selector switch failed
highOne of the most commonly reported causes for this code — check this first.
Wiring or connector fault
mediumA plausible cause — test and verify before replacing parts.
Related help
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