U0104 — Lost Communication With Cruise Control Module

OBD2 code U0104 flags a problem with the vehicle network (CAN bus) communication (lost communication with cruise control module). Short, gentle driving to a shop is usually possible. Common culprits: damaged CAN bus wiring or short to power/ground, corroded connectors, especially in wet areas, a faulty module pulling the bus down.

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 U0104 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 U0104 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for U0104 (parts and labor, USD, independent shop rates): Repair CAN wiring or connectors: $100–$400; Remove interfering aftermarket device: $0–$150; Replace the faulty control module: $300–$1,500. Overall, fixing U0104 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

Is it safe to drive with U0104?

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.

What does OBD2 code U0104 mean?

OBD2 code U0104 flags a problem with the vehicle network (CAN bus) communication (lost communication with cruise control module). Short, gentle driving to a shop is usually possible. Common culprits: damaged CAN bus wiring or short to power/ground, corroded connectors, especially in wet areas, a faulty module pulling the bus down.

What is the most common cause of U0104?

The most common causes are: damaged CAN bus wiring or short to power/ground, corroded connectors, especially in wet areas, a faulty module pulling the bus down.

Will U0104 clear itself?

Sometimes U0104 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.

How much does it cost to fix U0104?

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

What does U0104 mean?

U0104 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 Cruise Control Module”. This is a vehicle network category code.

To set U0104, the control module compares live readings of the vehicle network (CAN bus) communication against calibrated limits, usually over several drive cycles. Alongside the code it stores a freeze frame — a snapshot of rpm, load, coolant temperature and vehicle speed at the moment of failure. Reading that snapshot first saves diagnostic time.

What causes U0104?

  • damaged CAN bus wiring or short to power/ground
  • poor grounds or low battery voltage
  • a faulty module pulling the bus down
  • corroded connectors, especially in wet areas

Common symptoms of U0104

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

How to diagnose U0104

  1. Connect an OBD2 scanner, confirm U0104 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 U0104 does not return.

How to fix U0104

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

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

How much does it cost to fix U0104?

Repair cost depends on which component actually failed. Typical scenarios for U0104 (parts and labor, USD, independent shop rates):

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

Overall, fixing U0104 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 U0104?

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