Code result
U0001
High Speed CAN Communication Bus
High severity
What it means
A general fault on the high-speed CAN bus has been detected. This bus typically connects powertrain modules (ECM, TCM, ABS) at 500 kbit/s and a fault disables communication between them, often triggering multiple secondary DTCs in other modules.
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-High and CAN-Low shorted together
highOne of the most commonly reported causes for this code — check this first.
Open circuit in CAN bus wiring
highOne of the most commonly reported causes for this code — check this first.
Terminating resistor failed (not 60 ohms across bus)
mediumA plausible cause — test and verify before replacing parts.
Related help
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