AutoCodes – Buick – B0428 Buick

B0428 Buick Code - Auxiliary Air Temperature Actuator

Quick Answer

The Auxiliary Heating, Ventilation, and Air Conditioning (HVAC) actuators are a 5-wire bi-directional electric motor that incorporates a feedback potentiometer. Common causes include Faulty Auxiliary Air Temperature Actuator, Auxiliary Air Temperature Actuator harness is open or shorted, Auxiliary Air Temperature Actuator circuit poor electrical connection. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

What it means: B0428 Buick indicates Auxiliary Air Temperature Actuator.
Common causes: Common causes include Faulty Auxiliary Air Temperature Actuator, Auxiliary Air Temperature Actuator harness is open or shorted, Auxiliary Air Temperature Actuator circuit poor electrical connection.
Severity: Low - monitor the vehicle and repair when practical.
Can I drive?: The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

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Code Popularity 1,237

How popular is this code, among other codes? Low

Repair Importance Level

Low (Monitor) (1 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 11, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B0428 Buick Description

The Auxiliary Heating, Ventilation, and Air Conditioning (HVAC) actuators are a 5-wire bi-directional electric motor that incorporates a feedback potentiometer. Low reference, 5-volt reference, position signal, and 2 control circuits enable the actuator to operate. The control circuits use either a 0 or 12 volt value to coordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 0 volts. In order to move the actuator, the HVAC control module grounds one of the control circuits while providing the other with 12 volts. The auxiliary HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction. When the actuator shaft rotates, the potentiometers adjustable contact changes the door position signal between 0-5 volts. This signal then is converted into a count value where as 1 volt will equal 51 counts.
The auxiliary HVAC control module calibrates the travel range of the HVAC door actuators when it is initially powered by the battery positive voltage circuit. During calibration, the module commands the actuators in each direction until door travel is stopped. The module stores the minimum door positions and the maximum door positions of each actuator into memory. The total travel range is calculated by subtracting the minimum door position from the maximum door position.

OBDII Code B0428 Buick - Auxiliary Air Temperature Actuator - AutoCodes.com — B0428 Buick Code - Auxiliary Air Temperature Actuator

What does this mean?

What are the Possible Causes of the DTC B0428 Buick?

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

How to Fix the DTC B0428 Buick?

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 B0428 Buick 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 Help with the Code?

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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 B0428 Buick Code

1. What does OBDII code B0428 for the Buick Auxiliary Air Temperature Actuator indicate?

- This code indicates a problem with the auxiliary air temperature actuator in your Buick.

2. What are the common symptoms of a B0428 code in a Buick?

- Common symptoms include poor heater performance, incorrect air temperature readings, and issues with the HVAC system.

3. What are the possible causes of a B0428 code in a Buick?

- Potential causes include a faulty temperature actuator, wiring issues, a defective control module, or a blown fuse.

4. How can I diagnose a B0428 code related to the Auxiliary Air Temperature Actuator in my Buick?

- Diagnose by checking the actuator's wiring connections, testing the actuator's functionality, and inspecting the control module.

5. How can I repair a B0428 code in my Buick?

- Repair options may include replacing the faulty temperature actuator, repairing damaged wiring, resetting the control module, or replacing a blown fuse.

6. Can I drive my Buick with a B0428 code?

- It is not recommended to drive with a B0428 code as it may affect the HVAC system's performance and could lead to discomfort or further damage.

7. Is it possible to reset the B0428 code in a Buick without fixing the issue?

- While you can reset the code using an OBDII scanner, it is crucial to address the underlying problem to prevent it from recurring.

8. How much does it typically cost to repair a B0428 code in a Buick?

- The cost of repairs can vary depending on the exact cause of the issue, but it may range from $100 to $400 or more, including parts and labor.

9. Can a DIY enthusiast fix a B0428 code in a Buick?

- Depending on your skill level and access to tools, DIY enthusiasts may be able to address simpler causes of the B0428 code, such as replacing a fuse or checking wiring connections.

10. How long does it take to repair a B0428 code in a Buick?

- The repair time can vary based on the specific issue, but it may take anywhere from 1 to 3 hours for a professional technician to diagnose and fix the problem.