What Does U0164 Mean?
The vehicle network has lost communication with the HVAC (heating, ventilation, and air conditioning) control module. This prevents proper operation of climate control functions and may result in loss of heating, cooling, or fan operation.
Common Causes
35%
Failed HVAC control module or climate control head unit
25%
Corroded or disconnected connector at HVAC module
20%
Blown fuse in HVAC module power circuit
15%
Broken or shorted wiring between HVAC module and CAN bus
5%
Poor ground connection at HVAC control module
Diagnostic Steps
1
Step 1: Check if HVAC control panel illuminates and responds to button inputs
2
Step 2: Verify power and ground at HVAC module connector using multimeter
3
Step 3: Inspect all connectors at HVAC module for corrosion, moisture, or loose fit
4
Step 4: Measure CAN bus voltage at HVAC module (should see approximately 2.5V on each line)
5
Step 5: Attempt to command HVAC functions through scan tool bi-directional controls
Estimated Repair Cost
$200 - $800
Parts + labor, varies by vehicle and location
The vehicle network has lost communication with the HVAC (heating, ventilation, and air conditioning) control module. This prevents proper operation of climate control functions and may result in loss of heating, cooling, or fan operation.
The most common cause of U0164 (Lost Communication With HVAC Control Module) is: Failed HVAC control module or climate control head unit
Typical repair costs for U0164 range from $200 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Loss of climate control can cause driver discomfort and windshield defogging issues, potentially impairing visibility. In extreme weather conditions, this could affect safe vehicle operation.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0164 to identify the root cause.
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Quick Info
Category
Network
System
Climate Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
