U0102 — Lost Communication with Transfer Case Control Module

U0102 — Lost Communication with Transfer Case Control Module. A fault in the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Typical causes: a faulty module pulling the bus down, poor grounds or low battery voltage, aftermarket equipment interfering with the bus.

vehicle network

Is it safe to drive?

Drive with caution Depends on what is affected. A single dead convenience module is fine to drive with; loss of communication with engine, braking or steering modules is not. If multiple critical systems drop out, do not drive.

How to diagnose with an OBD scanner

  1. Read the code and freeze frame Connect an OBD2 scanner, confirm U0102 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
  2. Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many U0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
  3. Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the vehicle network (CAN bus) communication for damage, corrosion, chafing or poor contact.
  4. Subsystem check Measure resistance between CAN-High and CAN-Low at the OBD port with power off — about 60 Ω is healthy.
  5. Subsystem check Scan all modules: the one that does not respond is either the culprit or downstream of the break.
  6. Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm U0102 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for U0102 (parts and labor, USD, independent shop rates): Remove interfering aftermarket device: $0–$150; Replace the faulty control module: $300–$1,500; Repair CAN wiring or connectors: $100–$400. Overall, fixing U0102 usually costs between $0 and $1,500. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

How do I diagnose U0102 myself?

Start with a scan: confirm U0102, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the vehicle network (CAN bus) communication, and verify the suspect component against live data before buying parts.

How much does it cost to fix U0102?

Remove interfering aftermarket device — $0–$150; Replace the faulty control module — $300–$1,500; Repair CAN wiring or connectors — $100–$400. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

What does OBD2 code U0102 mean?

U0102 — Lost Communication with Transfer Case Control Module. A fault in the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Typical causes: a faulty module pulling the bus down, poor grounds or low battery voltage, aftermarket equipment interfering with the bus.

Is it safe to drive with U0102?

Depends on what is affected. A single dead convenience module is fine to drive with; loss of communication with engine, braking or steering modules is not. If multiple critical systems drop out, do not drive.

Will U0102 clear itself?

Sometimes U0102 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

What does U0102 mean?

U0102 is logged by the onboard diagnostics when the vehicle network (CAN bus) communication does not behave as expected. The official definition is “Lost Communication with Transfer Case Control Module”. This is a vehicle network category code.

This code does not appear from a single bad reading: the module must see the fault condition repeat under defined operating conditions before it turns on the warning light. The freeze frame captured with U0102 — engine load, rpm, temperature, speed — tells you exactly when the problem occurs, so reproduce those conditions when testing.

What causes U0102?

  • a faulty module pulling the bus down
  • damaged CAN bus wiring or short to power/ground
  • aftermarket equipment interfering with the bus
  • water ingress in harness junctions
  • poor grounds or low battery voltage

Common symptoms of U0102

  • random, hard-to-reproduce electrical glitches
  • modules intermittently not communicating with the scanner
  • intermittent loss of functions (gauges, windows, steering assist)
  • no-start or intermittent starting in some cases
  • multiple warning lights on at once

How to diagnose U0102

  1. Connect an OBD2 scanner, confirm U0102 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
  2. Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many U0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
  3. Visually inspect the wiring harness and connectors related to the vehicle network (CAN bus) communication for damage, corrosion, chafing or poor contact.
  4. Measure resistance between CAN-High and CAN-Low at the OBD port with power off — about 60 Ω is healthy.
  5. Scan all modules: the one that does not respond is either the culprit or downstream of the break.
  6. Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm U0102 does not return.

How to fix U0102

Start with the cheapest and most common causes before replacing expensive parts:

  • Remove interfering aftermarket device — $0–$150
  • Replace the faulty control module — $300–$1,500
  • Repair CAN wiring or connectors — $100–$400

How much does it cost to fix U0102?

Repair cost depends on which component actually failed. Typical scenarios for U0102 (parts and labor, USD, independent shop rates):

  • Remove interfering aftermarket device: $0–$150
  • Replace the faulty control module: $300–$1,500
  • Repair CAN wiring or connectors: $100–$400

Overall, fixing U0102 usually costs between $0 and $1,500. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Can you drive with U0102?

Depends on what is affected. A single dead convenience module is fine to drive with; loss of communication with engine, braking or steering modules is not. If multiple critical systems drop out, do not drive.

Related OBD2 codes