AutoCodes – GMC – B0428 GMC

B0428 GMC 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 GMC 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 1,517

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 GMC 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 GMC - Auxiliary Air Temperature Actuator - AutoCodes.com — B0428 GMC Code - Auxiliary Air Temperature Actuator

What does this mean?

What are the Possible Causes of the DTC B0428 GMC?

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 GMC?

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 GMC 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 B0428 GMC Code

1. What are the common symptoms of OBDII code B0428 GMC related to the Auxiliary Air Temperature Actuator?

- Common symptoms include issues with the vehicle's heating and cooling system, such as irregular temperature control or inconsistent airflow.

2. What are the possible causes of OBDII code B0428 GMC for the Auxiliary Air Temperature Actuator?

- The code may be triggered by a faulty auxiliary air temperature actuator, wiring issues, a malfunctioning HVAC control module, or a sensor problem.

3. How can I diagnose OBDII code B0428 GMC for the Auxiliary Air Temperature Actuator?

- Diagnosis typically involves using a scan tool to retrieve the specific trouble code, checking the wiring and connections related to the actuator, and testing the actuator and associated components for proper functionality.

4. Can I drive my vehicle with OBDII code B0428 GMC related to the Auxiliary Air Temperature Actuator?

- It is generally not recommended to drive the vehicle with this code present, as it can lead to discomfort and potential issues with the heating and cooling system.

5. How can I repair OBDII code B0428 GMC for the Auxiliary Air Temperature Actuator?

- Repair options may include replacing the faulty auxiliary air temperature actuator, repairing any damaged wiring, addressing issues with the HVAC control module, or resolving sensor malfunctions.

6. Are there any preventive measures to avoid OBDII code B0428 GMC related to the Auxiliary Air Temperature Actuator?

- Regular maintenance of the HVAC system, checking for wiring issues, and promptly addressing any temperature control problems can help prevent this code from appearing.

7. Will resetting the OBDII code B0428 GMC resolve the issue with the Auxiliary Air Temperature Actuator?

- Resetting the code may temporarily clear the warning light, but it will not fix the underlying problem causing the code to trigger. It is important to diagnose and repair the issue to prevent it from recurring.

8. Can a DIY enthusiast fix OBDII code B0428 GMC for the Auxiliary Air Temperature Actuator?

- Depending on the individual's skill level and knowledge of automotive systems, some DIY enthusiasts may be able to diagnose and repair this code. However, complex electrical issues may require professional assistance.

9. How long does it typically take to repair OBDII code B0428 GMC related to the Auxiliary Air Temperature Actuator?

- The repair time can vary based on the specific cause of the code and the extent of the issue. It can range from a quick fix to a more involved repair that may take several hours.

10. Is it necessary to visit a dealership for OBDII code B0428 GMC related to the Auxiliary Air Temperature Actuator?

- While a dealership may have specialized knowledge and tools for diagnosing and repairing this code, independent auto repair shops and skilled mechanics can also effectively address the issue, potentially at a lower cost.