Code result
U0138
Lost Communication with All Terrain Control Module
Moderate severity
What it means
The terrain mode / 4WD mode controller has dropped off the bus. Off-road and traction modes can no longer be selected; vehicle defaults to standard 2WD/AWD behaviour.
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
Module unpowered
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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