AutoCodes – Hummer – B0428 Hummer

B0428 Hummer 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 Hummer 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 2,609

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

What does this mean?

What are the Possible Causes of the DTC B0428 Hummer?

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 Hummer?

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 Hummer 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 Hummer Code

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

The B0428 code indicates a problem with the Auxiliary Air Temperature Actuator in a Hummer vehicle.

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

Common symptoms of a B0428 code may include issues with the heating and cooling systems, poor air circulation, or inconsistent temperature control in the vehicle.

3. What are some possible causes of a B0428 code in a Hummer?

Possible causes of a B0428 code can include a faulty Auxiliary Air Temperature Actuator, wiring issues, a malfunctioning temperature sensor, or a problem with the HVAC system.

4. How can I diagnose a B0428 code in my Hummer?

Diagnosing a B0428 code typically involves using an OBDII scanner to retrieve the code, checking the Auxiliary Air Temperature Actuator for proper function, inspecting wiring for damage, and testing the temperature sensor.

5. Can I still drive my Hummer with a B0428 code?

While it may be possible to drive with a B0428 code, it is recommended to address the issue promptly to prevent further damage to the HVAC system and ensure proper temperature control in the vehicle.

6. How can I repair a B0428 code in my Hummer?

Repairing a B0428 code may involve replacing the faulty Auxiliary Air Temperature Actuator, repairing any damaged wiring, replacing the temperature sensor, or addressing any other underlying issues in the HVAC system.

7. Are there any DIY tips for fixing a B0428 code in a Hummer?

DIY tips for addressing a B0428 code include checking and cleaning electrical connections, ensuring proper installation of a new Auxiliary Air Temperature Actuator, and following manufacturer guidelines for repairs.

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

The cost of repairing a B0428 code in a Hummer can vary depending on the specific issue, parts needed, labor costs, and whether the repair is done at a dealership or an independent mechanic.

9. How long does it take to fix a B0428 code in a Hummer?

The time it takes to fix a B0428 code in a Hummer can vary depending on the exact cause of the issue, availability of parts, and the expertise of the mechanic. It may take a few hours to a full day for repairs.

10. Can a B0428 code in a Hummer lead to other problems if left untreated?

If left untreated, a B0428 code in a Hummer can potentially lead to further damage to the HVAC system, poor temperature control, and reduced comfort while driving. It is best to address the issue promptly to avoid complications.