U0166 - Lost Communication With Auxiliary Heater Control Module

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3    What is this?
Table of contents

U0166 Possible Causes

  • Faulty Auxiliary Heater Control Module
  • Auxiliary Heater Control Module harness is open or shorted
  • Auxiliary Heater Control Module circuit poor electrical connection

How do I fix code U0166?

Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
Connect Your Car To The Future

Cost of diagnosing the U0166 code

Labor: 1.0

The cost of diagnosing the U0166 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

U0166 Description

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Operating information and commands are exchanged among the devices. The devices have programmed information about what messages are needed to be exchanged on the serial data circuits. CAN bus uses two dedicated wires for communication. The wires are called CAN high and CAN low. When the CAN bus is in idle mode, both lines carry 2.5V. When data bits are being transmitted, the CAN high line goes to 3.75V, and the CAN low drops to 1.25V, thereby generating a 2.5V differential between the lines. Since communication relies on a voltage differential between the two bus lines, the CAN bus is NOT sensitive to inductive spikes, electrical fields, or other noise. The Diagnostic Trouble Code (DTC) sets when a periodic message from the Auxiliary Heater Control Module has not been received.
OBDII Code U0166 - Lost Communication With Auxiliary Heater Control Module - AutoCodes.com

More Information

Need more information on how to fix the U0166 code?
Get Access to Factory Service Manuals

Information for specific makes

  • U0166 BUICK Lost Communication With Auxiliary Heater Control Module
  • U0166 CADILLAC Lost Communication With Auxiliary Heater Control Module
  • U0166 CHEVROLET Lost Communication With Auxiliary Heater Control Module
  • U0166 GMC Lost Communication With Auxiliary Heater Control Module

Need more help?

Get the U0166 code diagnosed by a professional: Find a repair shop in your area

Comments

Help us improve AutoCodes.com. Leave a comment below or tell us if the information above help you fix the code. What are the symptoms on your vehicle for the U0166 code? Have you replaced any parts?
Any information is appreciated. Thanks
Top ⇧