AutoCodes – GMC – P0979 2018 GMC Sierra

P0979 2018 GMC Sierra Code - Shift Solenoid Valve 3 Control Circuit Low Voltage

Quick Answer

The Transmission Control Module (TCM) high side driver 1 supplies 12 V to pressure control solenoid valve 3. Common causes include Faulty Shift Solenoid Valveâ€‰3, Shift Solenoid Valveâ€‰3 harness is open or shorted, Shift Solenoid Valveâ€‰3 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: P0979 2018 GMC Sierra indicates Shift Solenoid Valve 3 Control Circuit Low Voltage.
Common causes: Common causes include Faulty Shift Solenoid Valveâ€‰3, Shift Solenoid Valveâ€‰3 harness is open or shorted, Shift Solenoid Valveâ€‰3 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 221

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 Aug 05, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P0979 2018 GMC Sierra Description

The Transmission Control Module (TCM) high side driver 1 supplies 12 V to pressure control solenoid valve 3. The TCM also provides a control circuit and uses a low-side driver to control shift solenoid valve 3. The Diagnostic Trouble Code (DTC) will be set when the Transmission Control Module detects an open or a short to ground on the shift solenoid valve 3 control circuit for greater than 1 s.

OBDII Code P0979 2018 GMC Sierra - Shift Solenoid Valve 3 Control Circuit Low Voltage - AutoCodes.com — P0979 2018 GMC Sierra Code - Shift Solenoid Valve 3 Control Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P0979 2018 GMC Sierra?

Faulty Shift Solenoid Valveâ€‰3
Shift Solenoid Valveâ€‰3 harness is open or shorted
Shift Solenoid Valveâ€‰3 circuit poor electrical connection
Faulty Transmission Control Module (TCM)

How to Fix the DTC P0979 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 P0979 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 P0979 2018 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.