U0104

Universal

Lost Communication With Cruise Control Module

Definition source: General OBD-II reference catalog
Definition verification: Not independently verified for display.
Time: Varies by diagnosis and vehicle | Diagnostic difficulty: Medium
Medium Severity

The vehicle has detected that it is not receiving expected communication from the cruise control module over the vehicle network. Cruise control may be unavailable or may not operate normally. This code identifies a communication problem, not proof that the module itself has failed.

Report an error with this code

⚠️ Before You Begin (Safety First)

Do not rely on cruise control until the issue is diagnosed. If the vehicle’s speed or throttle behaves unexpectedly, pull over safely and have the vehicle inspected before continuing.

Common Symptoms

  • Cruise control may not engage or may stop working because its control module is not communicating.
  • A cruise-control warning or check-engine light may appear, depending on the vehicle.
  • Other driver-assistance or vehicle functions may be affected if they depend on information from the cruise control module; this varies by vehicle.
  • There may be no noticeable symptoms if the vehicle does not use the affected function or another module has recorded the communication loss.

Common Causes

  • A loose, damaged, or corroded connector or network wire may interrupt communication with the cruise control module.
  • A fuse, power-supply, or ground problem may prevent the module from operating or communicating.
  • Low or unstable vehicle voltage may disrupt module communication.
  • A fault elsewhere on the vehicle communication network may interfere with messages to or from the module.
  • The cruise control module may have an internal fault, but this should be confirmed after power, ground, wiring, and network operation are checked.

Diagnostic Steps

  1. Note when the warning appeared and whether cruise control or other functions changed; this can help a technician identify related conditions.
  2. Check the owner’s manual for cruise-control and warning-light guidance, and avoid using cruise control while the fault is present.
  3. With the vehicle safely parked and switched off, visually inspect accessible wiring and connectors for obvious damage, looseness, or corrosion. Do not unplug modules or probe network wires without vehicle-specific instructions.
  4. Check the vehicle battery for obvious signs of damage or loose connections. If you are unsure how to inspect battery connections safely, ask a qualified technician.
  5. If a scan tool is available, record the codes from all accessible modules before clearing anything. A basic engine-code reader may not access the cruise control or network modules.
  6. If the code returns or cruise control remains unavailable, arrange diagnosis using service information for the vehicle’s exact model, year, and engine.

When to Call a Professional

A technician can scan all accessible modules for related communication and power-supply codes, then check the cruise control module’s power, ground, connectors, and network wiring using vehicle-specific service information. Confirming that the module itself has failed requires testing the circuit and network first.

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Commonly Asked Questions

Does U0104 prove that the cruise control module needs replacement?

No. The code indicates lost communication with the module. Wiring, connectors, power, ground, voltage, or another network fault can cause the same condition.

Can I drive with U0104?

If the vehicle otherwise behaves normally, the main immediate concern may be that cruise control is unavailable. Do not rely on cruise control, and stop safely if speed or throttle response becomes abnormal.

Why might there be no noticeable symptoms?

Cruise control may not be in use, or the vehicle may continue operating without an obvious change while the communication fault is stored. Effects depend on how the vehicle uses the module.

What should be checked before replacing a part?

Check for related codes and verify the module’s power, ground, connectors, and network wiring using vehicle-specific service information. The module should be replaced only if testing supports that diagnosis.

Browse Available Code Guides

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