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Home/DTC Codes/Chevrolet/Spark EV/2014-2016 Electric Motor/U0166
U0166

Lost Communication with Auxiliary HVAC Control Module

2014-2016 Chevrolet Spark EV Electric Motor

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

  1. Check auxiliary HVAC fuse
  2. Test power and ground
  3. Check CAN wiring
  4. Test auxiliary heater element

Repair Notes

Check fuses for auxiliary climate system.

Related Codes

U0164Lost Communication with HVAC Control ModuleU0165Lost Communication with Rear HVAC Control Module

Other Network Codes

U0166 on Other Vehicles

Chevrolet Astro

1995-2005 4.3L V6 Vortec

Chevrolet Avalanche

2002-2006 5.3L V8 Vortec

Chevrolet Avalanche

2002-2006 8.1L V8 Vortec

Chevrolet Avalanche

2007-2013 5.3L V8 Vortec

Chevrolet Avalanche

2007-2013 6.0L V8 Vortec

Chevrolet Aveo

2012-2018 1.6L I4

Chevrolet Beat

2018-2021 1.2L I4

Chevrolet Beretta

1990-1996 2.2L I4

Common Questions

What does code U0166 mean on a 2014-2016 Chevrolet Spark EV?

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 Chevrolet Spark EV?

Common symptoms of U0166 include: Auxiliary heater not working, Pre-conditioning not available, Remote start climate control disabled.

What causes U0166 on a 2014-2016 Chevrolet Spark EV?

Common causes of U0166 include: Auxiliary HVAC module failure, CAN bus wiring, Module power loss, Fuse blown.

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