AutoCodes – GMC – B0408 2014 GMC Sierra

B0408 2014 GMC Sierra Code - Main Temperature Control Circuit

Quick Answer

Stepper motors are used for temperature regulation, air distribution control and recirculation door control. Common causes include Faulty Air Temperature Actuator, Air Temperature Actuator harness is open or shorted, 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: B0408 2014 GMC Sierra indicates Main Temperature Control Circuit.
Common causes: Common causes include Faulty Air Temperature Actuator, Air Temperature Actuator harness is open or shorted, 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 263

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 29, 2024

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code B0408 2014 GMC Sierra Description

Stepper motors are used for temperature regulation, air distribution control and recirculation door control. With the switches and dials on the HVAC controls, air temperature door position, mode door position and recirculation door position can be selected. The selected values are passed to the Heating, Ventilation, and Air Conditioning (HVAC) Control Module via serial data. The HVAC control module supplies a 12 V reference voltage to the stepper motors and energizes the 4 stepper motor coils with a pulsed ground signal. The stepper motors move the appropriate doors into the calculated positions, in order to reach the desired positions.

OBDII Code B0408 2014 GMC Sierra - Main Temperature Control Circuit - AutoCodes.com — B0408 2014 GMC Sierra Code - Main Temperature Control Circuit

What does this mean?

What are the Possible Causes of the DTC B0408 2014 GMC Sierra?

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

How to Fix the DTC B0408 2014 GMC Sierra?

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 does this mean?

Code Tech Notes

B0413:02 Main Temperature Control Circuit Short to Ground
B0413:05 Main Temperature Control Circuit Short to Battery or Open
B0413:61 Main Temperature Control Circuit Actuator Stuck Open

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B0408 2014 GMC Sierra 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 B0408 2014 GMC Sierra code?

Need more information on how to fix the B0408 2014 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B0408 2014 GMC Sierra 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 B0408 2014 GMC Sierra Code

1. What are the common symptoms of OBDII code B0408 on a 2014 GMC Sierra related to the Main Temperature Control Circuit?

- Common symptoms include inconsistent temperature control in the vehicle's HVAC system, the inability to adjust the temperature settings effectively, or the climate control system getting stuck on a specific temperature.

2. What are the typical causes of OBDII code B0408 in a 2014 GMC Sierra?

- The code B0408 for the Main Temperature Control Circuit in a 2014 GMC Sierra is often triggered by a faulty temperature control actuator, a malfunctioning blend door, wiring issues, or a defective HVAC control module.

3. How can I diagnose the issue causing OBDII code B0408 on my 2014 GMC Sierra?

- To diagnose the problem, it is recommended to use an OBDII scanner to retrieve the specific trouble code. Additionally, a thorough visual inspection of the HVAC components, checking the wiring for any damage, and testing the temperature control actuator can help pinpoint the cause.

4. Can I continue driving my 2014 GMC Sierra with OBDII code B0408 without immediate repair?

- It is not advisable to ignore OBDII code B0408 on a 2014 GMC Sierra, as it can lead to discomfort while driving and potentially affect the overall functionality of the HVAC system. Prompt diagnosis and repair are recommended.

5. How can I repair OBDII code B0408 on my 2014 GMC Sierra related to the Main Temperature Control Circuit?

- Repairing OBDII code B0408 may involve replacing the faulty temperature control actuator, addressing any wiring issues, or recalibrating the HVAC system. It is recommended to consult a professional mechanic for an accurate diagnosis and repair.

6. Are there any DIY tips for troubleshooting OBDII code B0408 on a 2014 GMC Sierra?

- DIY troubleshooting tips for OBDII code B0408 include checking the fuse related to the HVAC system, inspecting the wiring for any visible damage, and ensuring that the temperature control actuator is functioning correctly by testing its operation.

7. Is OBDII code B0408 a common issue in 2014 GMC Sierra vehicles?

- OBDII code B0408 related to the Main Temperature Control Circuit is a relatively common issue in 2014 GMC Sierra vehicles, especially as they age and the HVAC components undergo wear and tear.

8. Can extreme weather conditions affect the likelihood of OBDII code B0408 occurring in a 2014 GMC Sierra?

- Yes, extreme weather conditions can sometimes exacerbate issues related to OBDII code B0408 in a 2014 GMC Sierra, as the temperature control system works harder to maintain the desired cabin temperature, potentially leading to component failures.

9. Will resetting the OBDII codes clear OBDII code B0408 on a 2014 GMC Sierra?

- Resetting the OBDII codes may temporarily clear the code B0408, but it is likely to return if the underlying issue causing the fault is not addressed through proper diagnosis and repair.

10. How much can I expect to pay for repairing OBDII code B0408 on a 2014 GMC Sierra at a professional auto repair shop?

- The cost of repairing OBDII code B0408 on a 2014 GMC Sierra can vary depending on the specific cause of the issue, location, and labor rates. It is recommended to obtain quotes from reputable auto repair shops for an accurate estimate.