Engine-CodesGMC – P0979 2017 GMC Sierra

P0979 2017 GMC Sierra Code - Shift Solenoid Valve 3 Control Circuit Low Voltage

Quick Answer

The P0979 diagnostic trouble code (DTC) for a 2017 GMC Sierra indicates a problem with the Shift Solenoid Valve 3 Control Circuit experiencing low voltage. Common causes include Wiring harness issues (short circuits, open circuits), Damaged connectors, Faulty shift solenoid valve 3. 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 2017 GMC Sierra indicates Shift Solenoid Valve 3 Control Circuit Low Voltage.
Common causes
Common causes include Wiring harness issues (short circuits, open circuits), Damaged connectors, Faulty shift solenoid valve 3.
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.
Table of contents Created and updated by William Orellana on Sep 11, 2024
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Code P0979 2017 GMC Sierra Description

The P0979 diagnostic trouble code (DTC) for a 2017 GMC Sierra indicates a problem with the Shift Solenoid Valve 3 Control Circuit experiencing low voltage. In the context of the vehicle's transmission system, this code specifically points to an issue with the electrical circuit responsible for controlling the operation of the third shift solenoid valve. The shift solenoid valves play a crucial role in regulating the flow of transmission fluid to facilitate gear changes. When the PCM (Powertrain Control Module) detects a voltage level below the specified threshold in the control circuit for the third solenoid valve, it triggers the P0979 code.

OBDII Code P0979 2017 GMC Sierra - Shift Solenoid Valve 3 Control Circuit Low Voltage
P0979 2017 GMC Sierra Code - Shift Solenoid Valve 3 Control Circuit Low Voltage

Common Causes of P0979 2017 GMC Sierra

  1. Wiring harness issues (short circuits, open circuits)
  2. Damaged connectors
  3. Faulty shift solenoid valve 3
  4. Defective PCM
  5. Low transmission fluid levels

Symptoms of P0979 2017 GMC Sierra

  1. Erratic shifting behavior
  2. Harsh or delayed gear changes
  3. Transmission slipping
  4. Illumination of the Check Engine Light
  5. Reduced fuel efficiency

How to Fix P0979 2017 GMC Sierra

  1. Perform a thorough inspection of the wiring harness and connectors associated with the shift solenoid valve 3 control circuit.
  2. Test the shift solenoid valve 3 for proper operation and replace if necessary.
  3. Check the transmission fluid level and quality, topping up or replacing as needed.
  4. Inspect the PCM for any signs of damage or malfunction and reprogram or replace if required.
  5. Clear the DTC and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0979 2017 GMC Sierra

The typical repair costs for addressing a P0979 code on a 2017 GMC Sierra can range from $150 to $500, including parts and labor. However, actual costs may vary depending on the extent of the issue, the specific repairs needed, and the rates charged by auto repair shops. It's advisable to consult with a qualified mechanic or service center to obtain an accurate estimate based on your vehicle's condition and location. Keep in mind that diagnosis time and labor rates can vary, so it's essential to factor in these variables when budgeting for the repair.

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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.

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