AutoCodes – GMC – P0747 2017 GMC Sierra

P0747 2017 GMC Sierra Code - Transmission Control Solenoid Valve 1 Stuck On

Quick Answer

The solenoid actuator controls fluid pressure by moving the clutch 1-2-3-4-5-6 regulator valve that controls the fluid pressure to the 1-2-3-4-5-6 clutch. Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Transmission Control Solenoid Valve. 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: P0747 2017 GMC Sierra indicates Transmission Control Solenoid Valve 1 Stuck On.
Common causes: Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Transmission Control Solenoid Valve.
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 253

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 30, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0747 2017 GMC Sierra Description

The solenoid actuator controls fluid pressure by moving the clutch 1-2-3-4-5-6 regulator valve that controls the fluid pressure to the 1-2-3-4-5-6 clutch. The Solenoid Valve is an electronic pressure actuator that controls transmission line pressure based on current flow through its coil windings. As current flow is increased, the magnetic field produced by the coil moves the solenoid’s plunger further away from the exhaust port. Opening the exhaust port decreases the output fluid pressure regulated by the solenoid valve, which ultimately decreases line pressure.

OBDII Code P0747 2017 GMC Sierra - Transmission Control Solenoid Valve 1 Stuck On - AutoCodes.com — P0747 2017 GMC Sierra Code - Transmission Control Solenoid Valve 1 Stuck On

What does this mean?

What are the Possible Causes of the DTC P0747 2017 GMC Sierra?

Low transmission fluid level
Dirty transmission fluid
Faulty Transmission Control Solenoid Valve
Transmission Control Solenoid Valve harness is open or shorted
Transmission Control Solenoid Valve circuit poor electrical connection

How to Fix the DTC P0747 2017 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 does this mean?

Code Tech Notes

When a transmission solenoid has malfunctioned, in most cases the problem is not the electrical part of the solenoid; the problem is foreign material obstructing the mechanical function of the solenoid or the flow of the fluid through the transmission valve body. If the transmission fluid is dirty, it's recommended to change the transmission fluid and if possible, remove the transmission pan for further diagnosis. Excessive debris or metal particles on the transmission pan could be an indication that there is a mechanical transmission failure, and that the transmission will need to be rebuilt or replaced.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0747 2017 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 P0747 2017 GMC Sierra code?

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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 P0747 2017 GMC Sierra Code

1. What does the OBDII code P0747 mean on a 2017 GMC Sierra?

P0747 indicates that the Transmission Control Solenoid Valve 1 is stuck in the "on" position, preventing proper hydraulic pressure regulation in the transmission.

2. What are the common symptoms of the P0747 code?

Symptoms include harsh or delayed shifting, transmission slipping, a noticeable decrease in fuel efficiency, and the check engine light being illuminated.

3. What causes the P0747 code to appear on a 2017 GMC Sierra?

Common causes include a faulty transmission control solenoid, contaminated transmission fluid, internal transmission damage, or wiring and connector issues in the solenoid circuit.

4. Can I drive my 2017 GMC Sierra with the P0747 code active?

Driving with this code is not recommended, as it can cause further transmission damage and lead to more expensive repairs.

5. How is the P0747 code diagnosed?

A mechanic will typically check the transmission fluid condition, inspect the wiring and connectors for damage, perform a scan tool test on the solenoid, and possibly drop the transmission pan to inspect for debris.

6. What repairs can fix the P0747 code on a GMC Sierra?

Repairs may include replacing the transmission control solenoid, flushing and replacing the transmission fluid, repairing or replacing damaged wiring, or addressing internal transmission issues.

7. How much does it cost to fix the P0747 code on a 2017 GMC Sierra?

The cost depends on the underlying issue but typically ranges from $150 to $400 for solenoid replacement or up to $2,000 for major transmission repairs.

8. Can low transmission fluid cause the P0747 code?

Low or contaminated transmission fluid can contribute to this code by affecting the solenoid's ability to operate correctly.

9. How do I prevent the P0747 code from occurring?

Regularly servicing your transmission, including fluid changes, and inspecting the transmission system for wear or damage can help prevent this issue.

10. Will clearing the P0747 code with a scan tool fix the problem?

Clearing the code will not fix the underlying issue. The cause of the fault must be diagnosed and repaired to prevent the code from returning.