Basic checks
Veepeak OBDCheck BLE
A Bluetooth LE adapter for reading standard engine codes and supported live data.
View on AmazonU0164
Lost Communication with HVAC Control Module
Moderate severity
The HVAC Control Module has stopped transmitting on the vehicle data bus, so other control units no longer receive its messages. Automatic climate control stops responding. Typical causes are loss of power or ground at the module, an open or shorted CAN/LIN bus wire, a connector fault, or an internal module failure.
The HVAC Control Module has stopped transmitting on the vehicle data bus, so other control units no longer receive its messages. Automatic climate control stops responding. Typical causes are loss of power or ground at the module, an open or shorted CAN/LIN bus wire, a connector fault, or an internal module failure.
Common causes
- high
HVAC module unpowered
One of the most commonly reported causes for this code — check this first.
Typical part cost: $90-1100
- medium
CAN wiring to HVAC module broken
A plausible cause — test and verify before replacing parts.
Typical part cost: $90-1100
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First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
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Tools you may need
Already have a compatible scanner? Use it. If not, a Bluetooth OBD2 adapter can help you confirm engine codes and check supported live sensor data before replacing parts.
Regular diagnostics
vgate iCar Pro BLE 4.0
A Bluetooth LE adapter with an automatic sleep feature for routine code and sensor checks.
View on AmazonAnother option
OBDLink CX
A Bluetooth LE adapter to consider when comparing supported vehicles and diagnostic apps.
View on AmazonIllustrations shown, not product photos. Check vehicle, phone and app compatibility before buying. These adapters do not guarantee access to ABS, airbags or manufacturer-specific systems. Clearing a code does not repair the fault and can reset emissions readiness monitors.
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Related codes
See related trouble codes
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Frequently asked questions
What does U0164 mean?
U0164 means "Lost Communication with HVAC Control Module". It is a generic OBD-II code that points to a fault in the network / communication.
What are the most common causes of U0164?
hvac module unpowered; can wiring to hvac module broken; gateway module routing can messages incorrectly — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.
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