AutoCodes – GMC – C038D 2018 GMC Sierra

C038D 2018 GMC Sierra Code - Range Actuator Position Not Learned

Quick Answer

This is an internal programming fault detection of the transfer case control module. Common causes include Perform Range Actuator Learn Procedure. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: C038D 2018 GMC Sierra indicates Range Actuator Position Not Learned.
Common causes: Common causes include Perform Range Actuator Learn Procedure.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 216

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 11, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C038D 2018 GMC Sierra Description

This is an internal programming fault detection of the transfer case control module. No external circuits are involved.
This Diagnostic Trouble Code (DTC) is set anytime a transfer case control module is replaced or reprogrammed. The Range Actuator Learn procedure must be performed in order for the transfer case control module to learn current clutch tolerance based on clutch stack up and accumulated clutch wear.

OBDII Code C038D 2018 GMC Sierra - Range Actuator Position Not Learned - AutoCodes.com — C038D 2018 GMC Sierra Code - Range Actuator Position Not Learned

What does this mean?

What are the Possible Causes of the DTC C038D 2018 GMC Sierra?

Perform Range Actuator Learn Procedure

How to Fix the DTC C038D 2018 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the C038D 2018 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 C038D 2018 GMC Sierra code?

Need more information on how to fix the C038D 2018 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C038D 2018 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 C038D 2018 GMC Sierra Code

1. What does the OBDII code C038D mean on a 2018 GMC Sierra?

C038D indicates that the transfer case range actuator position has not been learned, meaning the system cannot confirm the actuator's position.

2. What are common symptoms of the C038D code on a GMC Sierra?

Common symptoms include the "Service 4WD" message on the dashboard, inability to shift into 4WD modes, or unusual noises when attempting to change drive modes.

3. What causes the C038D code to appear on a 2018 GMC Sierra?

Typical causes include a malfunctioning range actuator motor, wiring or connection issues, a faulty transfer case control module (TCCM), or mechanical issues within the transfer case.

4. How can I fix the C038D code on my GMC Sierra?

Fixes may include recalibrating the range actuator position, inspecting and repairing wiring or connectors, replacing the range actuator, or updating/reprogramming the TCCM.

5. Can I clear the C038D code without fixing the issue?

Clearing the code without addressing the underlying issue will likely result in the code reappearing. Proper diagnosis and repair are necessary.

6. Is it safe to drive with the C038D code active?

While driving may still be possible, the vehicle's 4WD functionality could be compromised, which may affect performance in off-road or slippery conditions.

7. How is the range actuator position learned on a GMC Sierra?

The range actuator position is learned through a calibration process performed with a scan tool capable of communicating with the transfer case control module.

8. Can a weak battery cause the C038D code on a GMC Sierra?

Yes, a weak or failing battery can cause communication or calibration issues with the transfer case control module, potentially triggering the code.

9. What tools are needed to diagnose the C038D code?

A professional-grade scan tool that can read transfer case-related codes and perform actuator position calibrations is necessary for proper diagnosis.

10. How much does it cost to repair the C038D code on a GMC Sierra?

Repair costs vary depending on the issue but may range from $100 for recalibration to $500 or more if the actuator or control module needs replacement.