Error code
OBD2 U0166
OBD2U0166
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.
What it means
Lost Communication With Auxiliary Heater Control Module.
Severity
moderateCan drive, but may experience issues with the auxiliary heating system.
Summary
U0166 indicates that the auxiliary heater control module is not communicating with the data bus. This issue affects the auxiliary heater system.
Common Causes
- Faulty auxiliary heater control module
- Disconnected or damaged wiring harness to the auxiliary heater control module
Fixes
FAQ
How can I diagnose U0166?
Use a diagnostic tool like Torque Pro to check for additional codes and inspect the wiring harness connecting the auxiliary heater control module.
Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.
More OBD2 codes
- U0100Lost Communication With ECM/PCM A
- U0101Lost Communication with TCM
- U0102Lost Communication with Transfer Case Control Module
- U0103Lost Communication With Gear Shift Module
- U0104Lost Communication With Cruise Control Module
- U0105Lost Communication With Fuel Injector Control Module
- U0106Lost Communication With Glow Plug Control Module
- U0107Lost Communication With Throttle Actuator Control Module
- U0108Lost Communication With Alternative Fuel Control Module
- U0109Lost Communication With Fuel Pump Control Module
- U0110Lost Communication With Drive Motor Control Module
- U0111Lost Communication With Battery Energy Control Module 'A'