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OBD-II · Network and communication (U)

U0102

Lost communication with transfer case control module

What it means

Another module has stopped receiving messages from the control unit that manages the four-wheel-drive transfer case.

Symptoms

  • 4x4 or AWD warning light
  • Four-wheel drive not engaging or stuck in one mode
  • Other warning lights may follow

Likely causes, most likely first

Likely causes, most likely first
No.Cause
01weak 12V battery
02blown fuse for the transfer case module
03water or corrosion in the module connector (often mounted low, near the transfer case)
04damaged CAN wiring
05failed transfer case control module

What to check, step by step

  1. 01Check 12V battery and fuses
  2. 02Check whether the transfer case module answers a scan tool
  3. 03Inspect the module connector and wiring under the car for water, road salt corrosion and damage
  4. 04Test power, ground and CAN lines at the module