U0166
Lost Communication with Auxiliary HVAC Control Module
2002-2007 Buick Rendezvous 3.5L V6
Low SeverityNetworkGeneric (SAE)
Description
Cannot communicate with auxiliary heater or auxiliary climate module.
Symptoms
- Auxiliary heater not working
- Pre-conditioning not available
- Remote start climate control disabled
Common Causes
- Auxiliary HVAC module failure
- CAN bus wiring
- Module power loss
- Fuse blown
Diagnostic Steps
- Check auxiliary HVAC fuse
- Test power and ground
- Check CAN wiring
- Test auxiliary heater element
Repair Notes
Check fuses for auxiliary climate system.
Related Codes
Other Network Codes
- U0001High Speed CAN Communication Bus
- U0002High Speed CAN Communication Bus Performance
- U0003High Speed CAN Communication Bus (+) Open
- U0004High Speed CAN Communication Bus (+) Low
- U0005High Speed CAN Communication Bus (+) High
- U0006High Speed CAN Communication Bus (-) Open
- U0007High Speed CAN Communication Bus (-) Low
- U0008High Speed CAN Communication Bus (-) High
- U0009High Speed CAN Communication Bus Shorted Together
- U0010Medium Speed CAN Communication Bus
U0166 on Other Vehicles
Common Questions
What does code U0166 mean on a 2002-2007 Buick Rendezvous?
U0166 stands for "Lost Communication with Auxiliary HVAC Control Module". Cannot communicate with auxiliary heater or auxiliary climate module.
What are the symptoms of U0166 on a Buick Rendezvous?
Common symptoms of U0166 include: Auxiliary heater not working, Pre-conditioning not available, Remote start climate control disabled.
What causes U0166 on a 2002-2007 Buick Rendezvous?
Common causes of U0166 include: Auxiliary HVAC module failure, CAN bus wiring, Module power loss, Fuse blown.