AutoCodes – Chevrolet – C0309 Chevrolet

C0309 Chevrolet Code - Motor A/B Circuit High

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: C0309 Chevrolet indicates Motor A/B Circuit High.
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 3,613

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 C0309 Chevrolet 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 C0309 Chevrolet - Motor A/B Circuit High - AutoCodes.com — C0309 Chevrolet Code - Motor A/B Circuit High

What does this mean?

What are the Possible Causes of the DTC C0309 Chevrolet?

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

How to Fix the DTC C0309 Chevrolet?

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 C0309 Chevrolet 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 C0309 Chevrolet code?

Need more information on how to fix the C0309 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C0309 Chevrolet 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 C0309 Chevrolet Code

1. What are the common symptoms of OBDII code C0309 (Motor A/B Circuit High) in a Chevrolet vehicle?

- Common symptoms include intermittent or constant illumination of the Check Engine Light, rough idling, engine misfires, and decreased fuel efficiency.

2. What can cause the OBDII code C0309 in a Chevrolet, indicating a Motor A/B Circuit High issue?

- Possible causes include a faulty motor A/B circuit, damaged wiring or connectors, a malfunctioning motor, or issues with the powertrain control module (PCM).

3. How can I diagnose the OBDII code C0309 in my Chevrolet related to Motor A/B Circuit High?

- Diagnosis typically involves using an OBDII scanner to read the trouble codes, inspecting the motor A/B circuit components, checking wiring for damage, and testing the motor's functionality.

4. Is it safe to continue driving with the OBDII code C0309 (Motor A/B Circuit High) present in a Chevrolet vehicle?

- It is generally not recommended to drive for an extended period with this issue, as it can lead to further damage and potentially affect the vehicle's performance.

5. What are some repair tips for resolving the OBDII code C0309 in a Chevrolet with a Motor A/B Circuit High problem?

- Repair tips may include repairing or replacing damaged wiring, connectors, or the motor itself, resetting the PCM, and ensuring all connections are secure and functioning properly.

6. Can I reset the Check Engine Light after resolving the OBDII code C0309 (Motor A/B Circuit High) in my Chevrolet?

- Yes, after fixing the underlying issue causing the code, you can reset the Check Engine Light using an OBDII scanner or by disconnecting the vehicle's battery for a few minutes.

7. How much does it typically cost to repair the OBDII code C0309 (Motor A/B Circuit High) in a Chevrolet at a mechanic or dealership?

- Repair costs can vary depending on the specific cause of the issue, but they may range from $100 to $500 or more, including parts and labor.

8. Can a DIY enthusiast with automotive knowledge fix the OBDII code C0309 (Motor A/B Circuit High) in a Chevrolet themselves?

- Depending on the individual's skill level and access to tools, some DIY enthusiasts may be able to diagnose and repair the issue themselves by following repair guides or consulting with experts.

9. Are there any recalls or technical service bulletins related to the OBDII code C0309 (Motor A/B Circuit High) in Chevrolet vehicles?

- It's advisable to check with Chevrolet dealerships or online databases for any recalls or technical service bulletins specific to this code and model to stay informed about potential known issues and solutions.

10. How long does it typically take to resolve the OBDII code C0309 (Motor A/B Circuit High) in a Chevrolet through professional repair?

- The repair time can vary based on the exact cause of the issue, but it may take anywhere from 1 to 3 hours or more for a mechanic to diagnose and fix the Motor A/B Circuit High problem.