Code result
U0409
Invalid Data Received from Vehicle Security Control Module
Moderate severity
What it means
The vehicle security / alarm controller is sending implausible status data (e.g. armed/unarmed jitter). Alarm and immobilizer behaviour can become unpredictable.
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
Security module internally failed
mediumA plausible cause — test and verify before replacing parts.
Gateway module routing CAN messages incorrectly
lowLess common, but worth ruling out after the more likely causes.
CAN terminating resistor (120 Ω) drifted out of spec
lowLess common, but worth ruling out after the more likely causes.
Related help
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