Code result
U0020
Low Speed CAN Communication Bus (+) Open
Moderate severity
What it means
The CAN-High wire of a low-speed comfort bus (e.g. ISO 11898-3 / fault-tolerant CAN) is open. Single-wire fallback may keep some functions alive but a fault is logged because the bus is no longer fault-tolerant.
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
CAN-High wire broken
highOne of the most commonly reported causes for this code — check this first.
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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