Network, generic

U0135 Lost Communication With Differential Control Module - Front

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U0135 reports that the front differential control module has dropped off the network. Such a module operates an electronically controlled clutch pack or locker in the front axle, either to move torque from one front wheel to the other or to lock both for traction off road. No manufacturer documents U0135 in public; the closest documented case is the rear counterpart U0136, which GM's 2019 ECM tables monitor on the Cadillac XT4. CARB requires a separate code for lost communication with a digital input but leaves driveline modules to the manufacturer unless other diagnostics rely on them. U0436 covers implausible front-differential data, U0114 and U0102 the AWD clutch and transfer case. The front differential then usually works as an open one.

Likely causes

Fuse, supply, ground or CAN wiring of the front differential module faulty
Water or corrosion in the connector near the front axle
Front differential control module internally faulty

Symptoms

  • 4WD, locker or traction warning lamp
  • Front locker or torque vectoring not available

Repair estimate

DifficultyHardWorkshop job
Parts and labour€80–2,000
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

front differential modulecan bus wiring

Related codes

U0436U0136U0114U0102

References: law.cornell.edu, en.wikipedia.org, gsi.ext.gm.com.