AutoCodes – Generic – B0238

B0238 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 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.

Save to My Repairs My Repairs

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

Code Popularity 2,857

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
Add Comment

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

Code B0238 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 - Air Flow Control 1 Circuit - AutoCodes.com — B0238 Code - Air Flow Control 1 Circuit

What does this mean?

What are the Possible Causes of the DTC B0238?

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?

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 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 code?

Need more information on how to fix the B0238 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B0238 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B0238 Buick — Air Flow Control 1 Circuit
B0238 Cadillac — Air Flow Control 1 Circuit
B0238 Chevrolet — Air Flow Control 1 Circuit
B0238 GMC — Air Flow Control 1 Circuit
B0238 Pontiac — Air Flow Control 1 Circuit
B0238 Saturn — Air Flow Control 1 Circuit

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 Code

1. What are the common symptoms of OBDII code B0238 - Air Flow Control 1 Circuit?

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

2. What are the potential causes of OBDII code B0238?

- Possible causes include a faulty air flow control valve, damaged wiring or connectors, a defective PCM, or a vacuum leak in the intake system.

3. How can I diagnose the issue related to OBDII code B0238?

- Diagnosing the issue involves using a scan tool to retrieve the code, inspecting the air flow control system components, checking for loose connections, and testing the air flow control valve.

4. Can I continue driving my vehicle with OBDII code B0238?

- It is not recommended to drive your vehicle with this code present, as it can lead to further damage to the engine and potentially worsen performance.

5. How can I repair OBDII code B0238 - Air Flow Control 1 Circuit?

- Repair options may include replacing the air flow control valve, repairing or replacing damaged wiring, ensuring proper connections, or addressing any vacuum leaks in the intake system.

6. Will resetting the OBDII code B0238 fix the issue?

- Simply resetting the code may temporarily clear the warning light, but it will not fix the underlying issue causing the code to trigger.

7. How do I prevent OBDII code B0238 from occurring again in the future?

- Regular maintenance, such as checking and replacing air filters as recommended, can help prevent issues with the air flow control system that trigger this code.

8. How serious is OBDII code B0238 - Air Flow Control 1 Circuit?

- While the severity can vary, it is important to address this code promptly to prevent potential engine damage and ensure optimal vehicle performance.

9. Can a DIY enthusiast fix OBDII code B0238 at home?

- Depending on your skill level and access to tools, some individuals may be able to diagnose and repair this code at home. However, professional assistance may be needed for complex issues.

10. How long does it typically take to repair OBDII code B0238?

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