AutoCodes – Chevrolet – U0166 Chevrolet

U0166 Chevrolet Code - Lost Communication With Auxiliary Heater Control Module

Quick Answer

Modules connected to the high speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Auxiliary Heater Control Module, Auxiliary Heater Control Module harness is open or shorted, Auxiliary Heater Control Module circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: U0166 Chevrolet indicates Lost Communication With Auxiliary Heater Control Module.
Common causes: Common causes include Faulty Auxiliary Heater Control Module, Auxiliary Heater Control Module harness is open or shorted, Auxiliary Heater Control Module circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 1,659

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 02, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0166 Chevrolet Description

Modules connected to the high speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. The supervision time-out period is 250 ms. Each message contains the identification number of the transmitter module. The Diagnostic Trouble Code (DTC) sets when a periodic message from the Auxiliary Heater Control Module has not been received.

OBDII Code U0166 Chevrolet - Lost Communication With Auxiliary Heater Control Module - AutoCodes.com — U0166 Chevrolet Code - Lost Communication With Auxiliary Heater Control Module

What does this mean?

What are the Possible Causes of the DTC U0166 Chevrolet?

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

How to Fix the DTC U0166 Chevrolet?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U0166 Chevrolet code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about U0166 Chevrolet Code

1. What are the common symptoms of OBDII code U0166 in a Chevrolet related to lost communication with the auxiliary heater control module?

- Common symptoms may include the auxiliary heater not functioning properly, a check engine light illuminated on the dashboard, and potential issues with the vehicle's heating system.

2. What are some possible causes of OBDII code U0166 in a Chevrolet?

- The code U0166 can be triggered by issues such as a faulty auxiliary heater control module, damaged wiring or connectors, a blown fuse, or a communication network problem within the vehicle.

3. How can I diagnose the issue causing OBDII code U0166 in my Chevrolet?

- Proper diagnosis involves using a scan tool to retrieve the specific fault codes present in the vehicle's system, checking the wiring and connectors for any visible damage, and testing the auxiliary heater control module for functionality.

4. Is it safe to continue driving my Chevrolet with OBDII code U0166 present?

- It is generally not recommended to continue driving the vehicle with the code U0166 present, as it can lead to further issues with the auxiliary heater system and potentially affect the overall performance of the vehicle.

5. Can I repair OBDII code U0166 in my Chevrolet by myself, or do I need professional assistance?

- While some basic troubleshooting steps can be taken by DIY enthusiasts, resolving the underlying cause of the code U0166 may require specialized knowledge and tools, making professional assistance advisable in many cases.

6. Are there any quick repair tips for addressing OBDII code U0166 in a Chevrolet?

- Quick repair tips may include checking and replacing any blown fuses related to the auxiliary heater system, inspecting the wiring for damage, and ensuring all connectors are properly connected and secure.

7. How much can I expect to pay to fix OBDII code U0166 in my Chevrolet at a repair shop?

- The cost of fixing OBDII code U0166 can vary depending on the specific cause of the issue, but it may range from a few hundred to over a thousand dollars, considering parts and labor costs.

8. Will resetting the OBDII code U0166 in my Chevrolet make the problem go away permanently?

- Resetting the code may temporarily turn off the check engine light, but if the underlying issue causing code U0166 is not addressed, the problem is likely to reoccur.

9. Can extreme weather conditions impact the likelihood of encountering OBDII code U0166 in a Chevrolet?

- Extreme cold or hot weather conditions can potentially put additional strain on the auxiliary heater system, increasing the chances of issues related to code U0166 occurring.

10. How long does it typically take to repair OBDII code U0166 in a Chevrolet?

- The repair time for OBDII code U0166 can vary depending on the specific cause of the problem and the availability of parts, but it may take anywhere from a few hours to a full day to complete the repairs.