AutoCodes – GMC – P0746 2015 GMC Sierra

P0746 2015 GMC Sierra Code - Transmission Control Solenoid Valve 1 Stuck Off

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: P0746 2015 GMC Sierra indicates Transmission Control Solenoid Valve 1 Stuck Off.
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 209

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
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0746 2015 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 P0746 2015 GMC Sierra - Transmission Control Solenoid Valve 1 Stuck Off - AutoCodes.com — P0746 2015 GMC Sierra Code - Transmission Control Solenoid Valve 1 Stuck Off

What does this mean?

What are the Possible Causes of the DTC P0746 2015 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 P0746 2015 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 P0746 2015 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.

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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 P0746 2015 GMC Sierra Code

1. What does the OBDII code P0746 mean on a 2015 GMC Sierra?

P0746 indicates "Transmission Control Solenoid Valve 1 Stuck Off," meaning the transmission control module (TCM) has detected an issue with the performance or operation of the pressure control solenoid in the transmission.

2. What are the common symptoms of code P0746 in a 2015 GMC Sierra?

Symptoms may include harsh or erratic shifting, transmission slipping, inability to shift into certain gears, reduced fuel efficiency, or the vehicle entering "limp mode."

3. What causes the P0746 code to appear in a 2015 GMC Sierra?

Common causes include a faulty pressure control solenoid, low or dirty transmission fluid, a clogged transmission filter, wiring or connector issues, or internal transmission mechanical problems.

4. Can I still drive my 2015 GMC Sierra with a P0746 code?

Driving with a P0746 code is not recommended, as it can lead to further transmission damage. If the vehicle is in "limp mode," it should be inspected and repaired as soon as possible.

5. How do I diagnose a P0746 code in my 2015 GMC Sierra?

Diagnosis involves checking the transmission fluid level and condition, inspecting wiring and connectors for damage, testing the solenoid for proper operation, and scanning the TCM for additional codes.

6. How can I fix the P0746 code on my 2015 GMC Sierra?

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

7. How much does it cost to repair a P0746 code on a 2015 GMC Sierra?

Repair costs vary depending on the issue but may range from $150 to $500 for solenoid replacement and fluid service. Internal transmission repairs can cost significantly more.

8. Can low or dirty transmission fluid cause the P0746 code on a 2015 GMC Sierra?

Yes, low or contaminated transmission fluid can disrupt solenoid operation and trigger the P0746 code. Checking and addressing the fluid condition is a key step in diagnosing this issue.

9. What tools are needed to diagnose the P0746 code on a 2015 GMC Sierra?

Basic tools include an OBDII scanner, a transmission fluid dipstick (if applicable), a multimeter for testing electrical circuits, and possibly a service manual for solenoid specifications.

10. Is the P0746 code a common issue for the 2015 GMC Sierra?

While not extremely common, P0746 can occur, especially in vehicles with higher mileage or poor transmission maintenance. Regular fluid changes can help prevent this issue.