AutoCodes – Mercury – U0164 Mercury

U0164 Mercury Code - Lost Communication With HVAC Control Module

Quick Answer

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Common causes include Faulty Heating, Ventilation, and Air Conditioning (HVAC) Control Module, HVAC Control Module harness is open or shorted, HVAC 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: U0164 Mercury indicates Lost Communication With HVAC Control Module.
Common causes: Common causes include Faulty Heating, Ventilation, and Air Conditioning (HVAC) Control Module, HVAC Control Module harness is open or shorted, HVAC 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 828

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 U0164 Mercury 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 Heating, Ventilation, and Air Conditioning (HVAC) Control Module has not been received.

OBDII Code U0164 Mercury - Lost Communication With HVAC Control Module - AutoCodes.com — U0164 Mercury Code - Lost Communication With HVAC Control Module

What does this mean?

What are the Possible Causes of the DTC U0164 Mercury?

Faulty Heating, Ventilation, and Air Conditioning (HVAC) Control Module
HVAC Control Module harness is open or shorted
HVAC Control Module circuit poor electrical connection

How to Fix the DTC U0164 Mercury?

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 U0164 Mercury 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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Need more information on how to fix the U0164 Mercury code? Get Access to Factory Service Manuals

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Get the U0164 Mercury code diagnosed by a professional: Find a repair shop in your area

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 U0164 Mercury Code

1. What does the OBDII code U0164 mean on a Mercury vehicle?

U0164 indicates that the vehicle has lost communication with the HVAC (Heating, Ventilation, and Air Conditioning) control module.

2. What are common symptoms of the U0164 code in a Mercury?

Symptoms may include the climate control system not responding, failure of the heating or cooling system, or no communication with the HVAC module during diagnostics.

3. What causes the U0164 code to appear?

Common causes include a faulty HVAC control module, damaged wiring or connectors, issues with the CAN (Controller Area Network) bus system, or a blown fuse.

4. Can I drive my Mercury with the U0164 code?

Yes, but the HVAC system may not function properly, which could lead to discomfort or safety issues in extreme weather conditions.

5. How can I diagnose the U0164 code on my Mercury?

Start by checking the wiring and connectors to the HVAC module for damage or corrosion, and use a scan tool to verify CAN bus communication and test the module functionality.

6. What should I do if the HVAC control module is unresponsive?

If the module is unresponsive, it may need to be replaced or reprogrammed. Consult a professional technician for proper diagnostics.

7. Can a discharged or weak battery cause the U0164 code?

Yes, a weak or discharged battery can disrupt communication between modules, potentially triggering the U0164 code.

8. How much does it cost to fix the U0164 code on a Mercury?

Repair costs can vary depending on the issue but may range from $100 for wiring repairs to $500 or more for HVAC module replacement and programming.

9. Can a faulty fuse cause the U0164 code?

Yes, a blown or faulty fuse related to the HVAC system can interrupt power to the module and trigger the U0164 code.

10. Do I need to clear the U0164 code after repairs?

Yes, after resolving the issue, use a scan tool to clear the code and verify that it does not return.

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