U062D

Code

Generic U — Network/User

Lost Communication With A/C Refrigerant Distribution Valve Actuator “D”

Brand: Generic

Type: U — Network/User

Views: UK: 16 EN: 27 RU: 26

AI status

Completed

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Page language: EN

Causes

Open or short in wiring between HVAC/central gateway and refrigerant distribution valve actuator D
Failed actuator (motor, internal controller or position sensor)
Faulty HVAC control module, gateway or actuator control module
CAN/LIN bus fault or compromised network node (low battery, high resistance)
Poor connector connection (corrosion, bent pins, water intrusion)
Software mismatch or corrupted calibration in one of the modules

Symptoms

A/C distribution flaps or valve D does not move or moves intermittently
A/C performance degraded or incorrect refrigerant routing
HVAC control displays a fault or warning message
Related DTCs stored for other HVAC nodes or network errors
Blower or climate functions may revert to limp-home mode

What to check

Read all HVAC and network modules with a capable scan tool; record U062D and any related codes and freeze-frame data
Visually inspect the actuator D connector and wiring harness for damage, corrosion, or water
Check vehicle battery voltage and ground quality (low voltage can cause bus faults)
Verify other HVAC actuators and modules are communicating (scan tool live data)
Backprobe actuator connector to confirm supply voltage and ground present

Signal parameters

CAN bus: static voltage ~2.5 V on CAN High and CAN Low when idle; differential ~0 V at rest, toggling during communication
LIN bus (if used): idle voltage ~12 V (or Vb) pulled low for frames; check expected sleep/wake behavior
Actuator supply: typically 5 V reference for sensor or 12 V power feed for motor — verify present with key on
Actuator position sensor output: variable voltage within 0–5 V range (or manufacturer-specified) that changes with movement
Current draw: actuator motor current should rise when commanded; near 0 A with no command

Diagnostic algorithm

Confirm the code with a scan tool and note freeze-frame/live data. Clear codes and attempt to recreate the fault while observing live data.
Check battery voltage (key on and cranking). Ensure adequate voltage (>12 V idle) and good chassis/body ground connections.
Inspect actuator D connector and harness for physical damage, corrosion, water intrusion, pin push-out or bent pins. Repair any issues and retest.
With ignition on, backprobe the actuator connector: verify power feed(s), ground, and communication lines (CAN or LIN) are present and have expected idle voltages.
Use an oscilloscope or quality scan tool to watch the bus traffic. Confirm messages from the actuator (or its local module) are present. If bus is silent or messages corrupted, isolate by disconnecting suspect nodes to find the fault.
Check continuity and resistance between actuator connector and HVAC/gateway module for wiring opens/shorts; repair as needed.
If power/ground/communication are present at the actuator but it does not respond, test actuator operation by commanding it while monitoring current and position feedback. If no response, replace the actuator.
If actuator replacement does not clear the code, test or reflash the HVAC control module/gateway per manufacturer procedures or substitute a known-good module if available.
After repairs, clear codes and verify system operation through full function test and road test if applicable.
If intermittent, perform wiggle tests on harness while watching live data to reproduce connection-related faults.

Likely causes

Damaged connector or wiring to the actuator (most common)
Failed actuator electronics or position sensor
Bus communication fault (CAN/LIN) caused by another node dragging down the network
Faulty HVAC control module or gateway