AutoCodes – GMC – B0238 GMC

B0238 GMC Code - Air Flow Control 1 Circuit

Quick Answer

Stepper motors are used for temperature regulation, air distribution control and recirculation door control. Common causes include Faulty Defrost Actuator, Defrost Actuator harness is open or shorted, Defrost 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: B0238 GMC indicates Air Flow Control 1 Circuit.
Common causes: Common causes include Faulty Defrost Actuator, Defrost Actuator harness is open or shorted, Defrost 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 977

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 10, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B0238 GMC 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 B0238 GMC - Air Flow Control 1 Circuit - AutoCodes.com — B0238 GMC Code - Air Flow Control 1 Circuit

What does this mean?

What are the Possible Causes of the DTC B0238 GMC?

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

How to Fix the DTC B0238 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 B0238 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.

Need more information about the B0238 GMC 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 B0238 GMC Code

1. What are common symptoms of OBDII code B0238 GMC (Air Flow Control 1 Circuit)?

- Common symptoms include poor engine performance, rough idling, stalling, and reduced fuel efficiency.

2. What are the possible causes of OBDII code B0238 GMC?

- The code may be triggered by issues such as a faulty air flow control actuator, wiring problems, or a defective control module.

3. How can I diagnose the cause of OBDII code B0238 GMC?

- Diagnosing the code typically involves checking the air flow control actuator, inspecting the wiring for damage, and using a scan tool to analyze data from the control module.

4. Can a dirty air filter trigger OBDII code B0238 GMC?

- While a dirty air filter can affect engine performance, it is unlikely to directly cause OBDII code B0238. Focus on checking the air flow control components for issues.

5. Is it safe to continue driving with OBDII code B0238 GMC present?

- It is generally not recommended to drive with this code active, as it can lead to more severe engine problems if left unresolved. It is best to address the issue promptly.

6. How can I repair OBDII code B0238 GMC?

- Repairing the code may involve replacing the faulty air flow control actuator, repairing damaged wiring, or resetting the control module after fixing the underlying issue.

7. Can I reset OBDII code B0238 GMC without fixing the underlying problem?

- While you can clear the code with a scan tool, it will likely reappear if the root cause is not addressed. It is crucial to fix the issue to prevent further problems.

8. Are there any DIY tips for addressing OBDII code B0238 GMC?

- DIY enthusiasts can start by inspecting the air flow control components for visible damage, checking the wiring connections, and ensuring proper installation of any replaced parts.

9. How much does it cost to repair OBDII code B0238 GMC at a mechanic?

- The cost of repair can vary based on the specific issue causing the code and labor rates in your area. It's best to consult a mechanic for a diagnosis and estimate.

10. Can extreme weather conditions trigger OBDII code B0238 GMC?

- While extreme weather may indirectly affect the performance of certain components, the code is more likely to be caused by internal issues with the air flow control system.