Code result
U0009
High Speed CAN Communication Bus Shorted to Bus
High severity
What it means
CAN-High and CAN-Low are shorted together. The differential signal collapses to zero and the bus controller can no longer separate dominant from recessive bits, so all communication stops.
Is it safe to drive?
No — stop driving
This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly.
Most likely causes
CAN-H and CAN-L shorted together
highOne of the most commonly reported causes for this code — check this first.
Pinched harness behind a module
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.
Related help
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