U0102 U0102 is a generic network code: a module lost communication with the transfer case control module on a four-wheel or all-wheel-drive vehicle

Lost communication with transfer case control module

U0102 in short

U0102 means a computer lost contact with the transfer case control module on a four-wheel or all-wheel-drive vehicle. Owners report 4WD fault messages, shifting problems and stability warnings with it. A technician should read all codes and check the transfer case module, its wiring and software before parts are replaced.

On four-wheel and all-wheel-drive vehicles, a transfer case module controls how power is split. If other computers stop hearing it, they store U0102. The code identifies the missing module, not the faulty part.

A 2020 Explorer owner reports the ABS module storing U0102 and U0155 with a 4WD fault and a failed front axle disconnect actuator. Ford and Jeep bulletin summaries list U0102 on Super Duty, Explorer and Grand Cherokee models. A GM bulletin summary covers loss of high-speed network communication on 2007-2012 vehicles.

U0102 is not always about the transfer case itself; the same lost communication can come from the network or a related module.

Most likely causes

  1. Transfer case control module or actuator fault

    Supported by vehicle data
    Why it ranks here
    The 2020 Explorer owner reports a front axle disconnect actuator failure with U0102, and Ford bulletin summaries list U0102 on Super Duty 4x4 and Explorer AWD.
    What would change this
    Rises if 4WD faults appear with U0102 and the module does not respond. Falls if other modules also lost communication.

  2. Software or module-update issue

    Possible — needs testing
    Why it ranks here
    A Jeep bulletin summary for the 2021 Grand Cherokee lists U0102 with other codes set in the BSCM, and an F-150 owner saw U0102 after a recall computer update, but neither shows that software is the cause.
    What would change this
    Rises if a bulletin for the exact vehicle names this code. Falls if hardware tests bad.

  3. Network wiring or power problem

    Common general cause
    Why it ranks here
    A GM bulletin summary on loss of high-speed network communication shows shared network faults can drop modules, and TaT gives a lost-communication definition.
    What would change this
    Rises with many modules offline or intermittent codes. Falls if only the transfer case is silent.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Read every stored code from all modules and note whether U0155, 4WD fault or transmission codes are also stored.

    Low riskTool: scan tool that reads all modules

    • IfSeveral modules are offline or network codes are stored together

      It meansLook for a wider network, power or ground fault.

      Go to step 2

    • IfOnly the transfer case module is silent with a 4WD fault message

      It meansSuspect the module, its actuator or its connector.

      Go to step 2

  2. Have a technician check the transfer case module power, ground, connectors and actuator, and look for a service bulletin or software update for the exact vehicle.

    Best left to a shop

    Warning:Drivetrain faults can change how the vehicle behaves while driving; leave testing and repair to a trained technician.

Symptoms

  • 4WD or AWD fault message
  • Transmission skips gears or shifts hard Gets more serious: stop and have it checked.
  • Stability or traction warnings
  • Rear tires lock under braking or shifting Gets more serious: stop and have it checked.

How to fix

Parts and cost context

  • Transmission control module (TCM):U0102 often appears with transmission codes, but this code is about the transfer case module; no transfer case module page exists yet; labor varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Ford

  • SSM 49045Status unverified

    Explorer AWD

    2020explorer · issued · NHTSA 10179311

    Special service message whose summary lists U0102. Only the NHTSA summary was read.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • SSM 48300Status unverified

    Super Duty 4x4 transfer case function inoperative

    2017–2019f-250-super-duty · issued · NHTSA 10168771

    Covers a transfer case that does not function; summary lists U0102. Only the NHTSA summary was read.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Jeep

  • S2108000149Status unverified

    U0159, U015C, U0102 and/or U1070 set in the BSCM

    2021grand-cherokee · issued · NHTSA 10212465

    Lists those codes as set in the BSCM. Only the NHTSA summary was read.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Ram

Pontiac

  • U0155Lost communication with the instrument panel cluster

    Same system Supported by vehicle data

    U0155 (lost communication with the instrument cluster) was stored with U0102 on a 2020 Explorer.

  • U0100Lost communication with the engine or powertrain computer

    Same system Supported by vehicle data

    The GM bulletin summary on lost high-speed network communication lists U0073, U0100, U0101, U0102, U0121 and U0140 together.

All Module network (CAN bus) communication codes

U0102 questions

Does U0102 always mean the transfer case module is bad?

No. It means a computer lost contact with that module, which can come from the module, its wiring, power, software or the network. A technician should test before replacing parts.

Sources and review

  1. NHTSA complaint ODI 11764430: 2020 Ford Explorer — NHTSA (owner complaint)
  2. NHTSA complaint ODI 11669928: 2017 Ford F-150 — NHTSA (owner complaint)
  3. Ford SSM 48300 (NHTSA 10168771): Super Duty 4x4 transfer case function inoperative — NHTSA (manufacturer communication)
  4. NHTSA complaint ODI 11338511: 2015 Ram 1500 — NHTSA (owner complaint)
  5. Ford SSM 49045 (NHTSA 10179311): Explorer AWD — NHTSA (manufacturer communication)
  6. Jeep S2108000149 (NHTSA 10212465): U0159, U015C, U0102 and/or U1070 set in the BSCM — NHTSA (manufacturer communication)
  7. GM 08-07-30-021G (NHTSA 10043829): loss of high speed GMLAN communications — NHTSA (manufacturer communication)
  8. U0102 Lost Communication with Transfer Case Control Module (TaT Scandata) — TaT Scandata fault code library
  9. NHTSA complaint ODI 10783716: 2007 Pontiac Torrent — NHTSA (owner complaint)
Last reviewed
Written by
Saurabh K.
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