AutoCodes – Buick – C0308 Buick

C0308 Buick 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 Buick 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 881

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

What does this mean?

What are the Possible Causes of the DTC C0308 Buick?

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 Buick?

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 Buick 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 Buick Code

1. What does the OBDII code C0308 mean on a Buick?

C0308 indicates a problem with the Motor A/B Circuit, specifically a low voltage condition detected in the circuit responsible for controlling a motor, often related to the transfer case or driveline system.

2. What are the common symptoms of the C0308 code on a Buick?

Symptoms may include the Service 4WD light illuminating, difficulty shifting into or out of 4WD modes, unusual noises from the transfer case, or a lack of response from the 4WD system.

3. What causes the C0308 code to appear in a Buick?

Common causes include a faulty transfer case motor, wiring issues such as damaged or corroded connectors, a blown fuse, or problems with the transfer case control module.

4. How can I diagnose the C0308 code on my Buick?

Start by inspecting the wiring and connectors for damage or corrosion. Check the transfer case motor for proper operation, and test the voltage at the circuit to verify if itâ€™s below specification.

5. Can a poor ground connection cause the C0308 code?

Yes, a poor ground connection can lead to voltage issues in the Motor A/B Circuit, triggering the C0308 code.

6. Is it safe to drive a Buick with the C0308 code active?

While the vehicle may still operate in 2WD, driving with this code active can lead to further damage to the driveline or transfer case system if not addressed promptly.

7. How do I fix the C0308 code on my Buick?

Repairs may include replacing the transfer case motor, repairing or replacing damaged wiring or connectors, or addressing issues with the transfer case control module.

8. Can a software update fix the C0308 code in a Buick?

In some cases, reprogramming or updating the transfer case control module software may resolve the issue if itâ€™s due to a software-related glitch.

9. What tools are needed to troubleshoot the C0308 code?

Youâ€™ll need an OBDII scanner capable of reading manufacturer-specific codes, a multimeter for voltage testing, and possibly a wiring diagram for the transfer case circuit.

10. How much does it cost to repair the C0308 code on a Buick?

The cost varies depending on the exact cause. Replacing a transfer case motor may cost $200â€“$500, while fixing wiring or connectors is typically less expensive.