AutoCodes – GMC – P0974 2018 GMC Sierra

P0974 2018 GMC Sierra Code - Shift Solenoid Valve 1 Control Circuit High Voltage

Quick Answer

The shift solenoid 1 is part of the control solenoid valve assembly which has no serviceable parts. 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: P0974 2018 GMC Sierra indicates Shift Solenoid Valve 1 Control Circuit High Voltage.
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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 458

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 Mar 25, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P0974 2018 GMC Sierra Description

The shift solenoid 1 is part of the control solenoid valve assembly which has no serviceable parts. The shift solenoid 1 is a normally closed ON/OFF solenoid and is controlled by the Transmission Control Module through a low side driver. When the shift solenoid 1 is energized, shift solenoid 1 fluid pressure is directed to the clutch select valve 2. Power to the shift solenoid 1 is supplied by the Transmission Control Module through a high-side driver. The high-side driver protects the circuit and components from excessive current flow. If excessive current flow is detected, the high side driver will turn OFF. When the fault is corrected, the high-side driver will reset. The Diagnostic Trouble Code (DTC) will be set when the control solenoid valve assembly detects an internal high voltage electrical malfunction of the shift solenoid 1 control circuit when the shift solenoid 1 is commanded ON for 2 seconds.

OBDII Code P0974 2018 GMC Sierra - Shift Solenoid Valve 1 Control Circuit High Voltage - AutoCodes.com — P0974 2018 GMC Sierra Code - Shift Solenoid Valve 1 Control Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P0974 2018 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 P0974 2018 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0974 2018 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 P0974 2018 GMC Sierra code?

Need more information on how to fix the P0974 2018 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0974 2018 GMC Sierra 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 P0974 2018 GMC Sierra Code

1. What are the common symptoms of OBDII code P0974 in a 2018 GMC Sierra?

- Common symptoms include harsh shifting, delayed or erratic gear shifts, transmission slipping, and decreased fuel efficiency.

2. What causes the Shift Solenoid Valve 1 Control Circuit High Voltage code (P0974) in a 2018 GMC Sierra?

- The code P0974 is usually triggered by issues such as a faulty shift solenoid, damaged wiring or connectors, low transmission fluid levels, or a defective transmission control module.

3. How can I diagnose the Shift Solenoid Valve 1 Control Circuit High Voltage code (P0974) on my 2018 GMC Sierra?

- Diagnosing P0974 involves conducting a thorough inspection of the shift solenoid, checking the wiring for any damage, testing the transmission fluid level, and using a scan tool to retrieve the trouble codes.

4. Can I continue driving my 2018 GMC Sierra with OBDII code P0974 present?

- It is not recommended to drive with the P0974 code present as it can lead to further damage to the transmission and potentially result in costly repairs. It's best to address the issue promptly.

5. How can I repair OBDII code P0974 in my 2018 GMC Sierra?

- Repairing the P0974 code may involve replacing the shift solenoid valve, repairing or replacing damaged wiring or connectors, ensuring proper transmission fluid levels, and resetting the trouble codes using a scan tool.

6. Is it possible to reset the OBDII code P0974 in a 2018 GMC Sierra without fixing the underlying issue?

- While you can reset the trouble codes using a scan tool, it's important to address the root cause of the P0974 code to prevent it from recurring and potentially causing further damage to the transmission.

7. How much does it typically cost to repair OBDII code P0974 in a 2018 GMC Sierra?

- The cost of repairing the P0974 code can vary depending on the underlying issue, the labor rates in your area, and whether you tackle the repair yourself or take it to a professional mechanic. Costs may range from a few hundred to over a thousand dollars.

8. Can a DIY enthusiast fix OBDII code P0974 in a 2018 GMC Sierra?

- While some DIY enthusiasts may have the skills and tools to address the P0974 code, it's recommended to have a professional diagnose and repair transmission-related issues due to their complexity and importance in vehicle operation.

9. What other related OBDII codes might be triggered along with P0974 in a 2018 GMC Sierra?

- Related codes that might be triggered alongside P0974 include P0973 (Shift Solenoid Valve 1 Control Circuit Low), P0975 (Shift Solenoid Valve 1 Control Circuit Range/Performance), and P0976 (Shift Solenoid Valve 1 Control Circuit Low).

10. How can I prevent OBDII code P0974 from occurring in my 2018 GMC Sierra in the future?

- To prevent the P0974 code from occurring, it's essential to maintain your vehicle's transmission system regularly, address any transmission fluid leaks promptly, and ensure the electrical connections related to the shift solenoid are in good condition.