OBD-II code · Network
U0164 Lost Communication with HVAC Control Module
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.
Is it safe to drive with U0164?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyHVAC module unpowered
- PossibleCAN wiring to HVAC module broken
- Less likelyGateway module routing CAN messages incorrectly
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
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–4 h
- Emissions test
- Usually unaffected
- Parts involved
- HVAC Control Module, Can Bus Wiring
Related codes
- U0161Lost Communication with Compass Module
- U0162Lost Communication with Navigation Display Module
- U0163Lost Communication with Navigation Control Module
- U0165Lost Communication with Auxiliary HVAC Control Module
- U0166Lost Communication with Auxiliary Heater Control Module
- U0167Lost Communication with Vehicle Immobiliser Control Module
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.