U0166low severityNetwork
Lost Communication with Auxiliary HVAC Control Module
on 2023 Chevrolet Bolt EUV 65 kWh Single Motor FWD · FWD
What this code means
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.
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Other Network codes on this vehicle
U0001
High Speed CAN Communication Bus
U0002
High Speed CAN Communication Bus Performance
U0003
High Speed CAN Communication Bus (+) Open
U0004
High Speed CAN Communication Bus (+) Low
U0005
High Speed CAN Communication Bus (+) High
U0006
High Speed CAN Communication Bus (-) Open
U0007
High Speed CAN Communication Bus (-) Low
U0008
High Speed CAN Communication Bus (-) High
U0009
High Speed CAN Communication Bus Shorted Together
U0010
Medium Speed CAN Communication Bus