What it means
The vehicle bus reports loss of communication with smart A/C refrigerant distribution valve actuator B. Routing of refrigerant between cabin / battery / power-electronics chillers cannot be commanded.
How it works
A/C refrigerant distribution valve actuator B is a networked valve that routes refrigerant among circuits fitted to the vehicle, which may include the cabin, battery, or power electronics chillers. The control system expects actuator B to report over the vehicle bus so its position can be commanded. U062B sets when those messages are lost and actuator B's routing cannot be controlled.
Common causes
Most likely first.
- Bus wiring open or shorted
- Module without power or ground
- Module failed
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Scan all modules and record event data to identify affected thermal functions and check whether actuator B is the only distribution valve offline.
- Check live data and command status for distribution valve actuator B, comparing it with actuators A, C, or D if equipped.
- Inspect actuator B's connector and accessible communication wiring for corrosion, looseness, chafing, or damage.
- Check actuator B's power and ground against the manufacturer's specification and observe the vehicle's required high-voltage safety procedure.
- Test the communication circuit to actuator B for opens or shorts using the vehicle wiring diagram and manufacturer's procedure.
Common fixes
- Repair or secure actuator B's connector or damaged bus wiring.
- Restore the actuator's power or ground.
- Repair an open or short in the communication circuit serving actuator B.
- Replace actuator B if its supplies and wiring are sound but it does not communicate.
Can I keep driving?
Cooling or battery and power electronics thermal management may be limited, and the vehicle may reduce power or disable affected functions. Treat any reduced-power or thermal warning seriously and stop if the vehicle indicates it is unsafe to continue.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.