AutoCodes – Generic – B0428

B0428 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 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 2,731

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

What does this mean?

What are the Possible Causes of the DTC B0428?

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?

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 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.

Need more information about the B0428 code?

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Need Help with the Code?

Get the B0428 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B0428 Buick — Auxiliary Air Temperature Actuator
B0428 Cadillac — Auxiliary Air Temperature Actuator
B0428 Chevrolet — Auxiliary Air Temperature Actuator
B0428 GMC — Auxiliary Air Temperature Actuator
B0428 Hummer — Auxiliary Air Temperature Actuator
B0428 Pontiac — Auxiliary Air Temperature Actuator
B0428 Saturn — Auxiliary Air Temperature Actuator

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 Code

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

- Common symptoms include poor heater performance, inconsistent airflow from vents, and potential issues with the heating and cooling system.

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

- Possible causes may include a faulty actuator motor, a malfunctioning temperature sensor, electrical issues, or a problem with the HVAC control module.

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

- Diagnosis typically involves using an OBDII scanner to retrieve the specific code, testing the actuator motor and temperature sensor, and checking the HVAC system components for any faults.

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

- While the vehicle may still be operable with this code, it is recommended to address the issue promptly to prevent further damage to the heating and cooling system.

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

- Repair options may include replacing the faulty actuator motor or temperature sensor, repairing any electrical connections, or recalibrating the HVAC control module.

6. Is it possible to reset OBDII code B0428 for the Auxiliary Air Temperature Actuator without repairs?

- Resetting the code without addressing the underlying issue may temporarily clear the warning light, but the problem will likely reoccur until the root cause is fixed.

7. Are there any DIY tips for troubleshooting OBDII code B0428 related to the Auxiliary Air Temperature Actuator?

- DIY tips may include checking for loose connections, inspecting the actuator for physical damage, and ensuring proper voltage supply to the actuator motor.

8. How much does it typically cost to repair OBDII code B0428 for the Auxiliary Air Temperature Actuator at a mechanic?

- Repair costs can vary depending on the exact cause of the issue, but it may range from $100 to $400 for parts and labor.

9. Can a malfunctioning Auxiliary Air Temperature Actuator affect the overall performance of my vehicle?

- Yes, a malfunctioning actuator can impact the efficiency of the heating and cooling system, leading to discomfort for passengers and potentially affecting the vehicle's overall climate control.

10. Is it safe to continue driving my vehicle if OBDII code B0428 related to the Auxiliary Air Temperature Actuator is ignored?

- Ignoring this code may lead to ongoing issues with the heating and cooling system, so it is advisable to address the problem promptly to maintain the comfort and functionality of the vehicle.