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DTC codes / U06xx · Network communication / U062C

U062CLost Communication With A/C Refrigerant Distribution Valve Actuator C

U062C is a generic network communication code indicating that a control module on the vehicle's Controller Area Network (CAN) bus has lost contact with the A/C refrigerant distribution valve actuator C. The computer has detected that the expected periodic messages from this actuator are missing, so it cannot command the valve to direct refrigerant flow where needed.

SystemNetwork
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaNetwork communication

Symptoms you may notice

  • The air conditioning may blow warm air on one side or from certain vents while working normally elsewhere.
  • The climate control system may default to a fixed temperature or blower speed and ignore your settings.
  • A yellow A/C or service vehicle soon warning light illuminates on the dashboard.
  • The A/C compressor clutch may fail to engage or may cycle rapidly because the system cannot confirm valve position.
  • Often no symptoms besides the warning light, especially if the valve is stuck in a position that still provides acceptable cooling.
  • In some vehicles, the HVAC control panel buttons for temperature or mode may become unresponsive.

Common causes, most likely first

  1. A failed A/C refrigerant distribution valve actuator C, often due to an internal motor or position sensor fault.
  2. Damaged, corroded, or disconnected wiring at the actuator connector or along the harness to the actuator.
  3. A blown fuse or poor ground connection that supplies power to the actuator circuit.
  4. A faulty HVAC control module or body control module that is not transmitting or receiving CAN messages correctly.
  5. CAN bus communication faults such as a shorted or open data line between the actuator and the module.
  6. Low refrigerant charge or a system pressure fault that causes the actuator to shut down and stop communicating.
  7. Aftermarket accessories or improper previous repairs that disturbed the CAN bus wiring or connectors.

How to diagnose and fix it

  1. Connect a scan tool and read all stored codes in every module, then record freeze-frame data for U062C to see when the fault occurred.
  2. Visually inspect the actuator connector and the wiring harness for corrosion, chafing, or loose pins, and repair any obvious damage.
  3. Check the fuse and ground for the actuator circuit with a multimeter, and verify battery voltage at the actuator connector with the key on.
  4. Perform a CAN bus voltage check at the diagnostic link connector (DLC) to confirm the bus is not shorted or open, which would affect multiple modules.
  5. If wiring and power are good, substitute a known-good actuator of the same part number and clear the code to see if communication returns.
  6. Use a scan tool to command the actuator through its full range and watch for position feedback; a missing or erratic feedback confirms an actuator fault.
  7. If the actuator responds but the code persists, check for software updates or known communication issues for the HVAC control module before replacing it.

What most technicians miss on U062C

  • A weak or failing battery can cause intermittent CAN communication codes like U062C because modules drop offline during cranking, so always load-test the battery before condemning the actuator.
  • The actuator often shares a power or ground circuit with other HVAC actuators, so a single corroded splice can set multiple U-codes that point away from the real culprit.
  • Aftermarket remote starters or alarm systems tapped into the CAN bus are a common cause of lost communication codes that disappear after the accessory is removed.
  • U062C can be set by a low refrigerant charge because the actuator may stop communicating when system pressure is outside its expected range, so check pressures before replacing parts.
  • A code reader that only reads engine modules will not show U062C; you need a tool that can access the HVAC or body control module to diagnose this fault properly.

Can I keep driving with U062C?

You can usually drive the vehicle safely because the fault mainly affects air conditioning comfort, but avoid long trips in hot weather if cooling is inconsistent. Do not ignore the warning light for weeks, because a communication fault can spread to other modules and cause unrelated electrical symptoms.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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