AutoCodes – GMC – C0308 GMC

C0308 GMC Code - Motor A/B Circuit Low

Quick Answer

The transfer case motor is a bi-directional, permanent magnet, D.C. Common causes include Faulty Transfer Case Motor, Transfer Case Motor harness is open or shorted, Transfer Case Motor circuit poor electrical connection. 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: C0308 GMC indicates Motor A/B Circuit Low.
Common causes: Common causes include Faulty Transfer Case Motor, Transfer Case Motor harness is open or shorted, Transfer Case Motor circuit poor electrical connection.
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 3,992

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 Jun 18, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C0308 GMC Description

The transfer case motor is a bi-directional, permanent magnet, D.C. motor. When energized, (through Motor Control A or Motor Control B, the ground is provided by the opposing Motor Control circuit and then grounded through the transfer case shift control module ground circuit), the motor, through a series of gears, rotates a shaft which moves the mode and range forks to shift the transfer case between 4H, AUTO 4WD, 2H, N, and 4L ranges. While the transfer case motor is energized the transfer case shift control module also energizes the solenoid for the transfer case lock. The motor lock is disabled (locking action released) and free turning of the transfer case motor and sector shaft is then allowed.
This DTC detects a short to ground in Motor Control A or Motor Control B CKT.

OBDII Code C0308 GMC - Motor A/B Circuit Low - AutoCodes.com — C0308 GMC Code - Motor A/B Circuit Low

What does this mean?

What are the Possible Causes of the DTC C0308 GMC?

Faulty Transfer Case Motor
Transfer Case Motor harness is open or shorted
Transfer Case Motor circuit poor electrical connection

How to Fix the DTC C0308 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 C0308 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.

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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 C0308 GMC Code

1. What are the common symptoms of OBDII code C0308 GMC "Motor A/B Circuit Low"?

The common symptoms include difficulty shifting gears, erratic engine performance, and the vehicle going into limp mode.

2. What are the possible causes of OBDII code C0308 GMC "Motor A/B Circuit Low"?

Possible causes include a faulty motor A/B circuit, damaged wiring or connectors, or a malfunctioning transfer case control module.

3. How can I diagnose the source of OBDII code C0308 GMC "Motor A/B Circuit Low"?

Diagnosis involves using a scan tool to read the trouble code, checking the wiring and connectors for any visible damage, and testing the components of the motor A/B circuit.

4. Can I still drive my vehicle with OBDII code C0308 GMC "Motor A/B Circuit Low"?

It is not recommended to drive the vehicle with this code present, as it can lead to further damage and safety issues. It's best to address the issue promptly.

5. What are some repair tips for fixing OBDII code C0308 GMC "Motor A/B Circuit Low"?

Repair tips include inspecting and repairing any damaged wiring or connectors, testing and replacing the transfer case control module if necessary, and clearing the trouble code.

6. Is it safe to reset the OBDII code C0308 GMC "Motor A/B Circuit Low" without fixing the underlying issue?

Resetting the code without addressing the root cause may temporarily turn off the check engine light, but the problem will likely resurface, leading to potential safety risks and further damage.

7. Can a DIY enthusiast fix OBDII code C0308 GMC "Motor A/B Circuit Low" at home?

While some basic troubleshooting steps can be done at home, diagnosing and repairing complex issues related to this code may require professional expertise and specialized tools.

8. How much does it typically cost to repair OBDII code C0308 GMC "Motor A/B Circuit Low" at a repair shop?

The cost of repair can vary depending on the exact cause of the issue, but it may involve diagnostic fees, replacement parts, and labor costs, which can range from a few hundred to over a thousand dollars.

9. How long does it take to fix OBDII code C0308 GMC "Motor A/B Circuit Low"?

The repair time can vary based on the complexity of the issue, availability of parts, and the expertise of the technician, but it generally takes a few hours to a full day to address this problem.

10. Are there any preventative maintenance measures to avoid OBDII code C0308 GMC "Motor A/B Circuit Low" in the future?

Regularly inspecting the transfer case components, keeping the wiring connections clean and secure, and addressing any issues promptly can help prevent the recurrence of this trouble code.