AutoCodesGMC – P0977 2015 GMC Sierra

P0977 2015 GMC Sierra Code - Shift Solenoid 'B' Open Or Short To Power

Quick Answer

The shift solenoid 2 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
P0977 2015 GMC Sierra indicates Shift Solenoid 'B' Open Or Short To Power.
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 204
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Mar 25, 2024
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Code P0977 2015 GMC Sierra Description

The shift solenoid 2 is part of the control solenoid valve assembly which has no serviceable parts. The shift solenoid 2 is a normally closed ON/OFF solenoid and is controlled by the Transmission Control Module through a low side driver. When the shift solenoid 2 is energized, shift solenoid 2 fluid pressure is directed to the clutch select valve 3. Power to the shift solenoid 2 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 Transmission Control Module detects an internal high voltage electrical malfunction of the shift solenoid 2 control circuit when the shift solenoid 2 is commanded ON for 2 seconds.
OBDII Code P0977 2015 GMC Sierra - Shift Solenoid 'B' Open Or Short To Power - AutoCodes.com
P0977 2015 GMC Sierra Code - Shift Solenoid 'B' Open Or Short To Power

What are the Possible Causes of the DTC P0977 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 P0977 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0977 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.

Need more information about the P0977 2015 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 P0977 2015 GMC Sierra Code

1. What does the OBDII code P0977 mean on a 2015 GMC Sierra?

P0977 indicates an issue with the Shift Solenoid 'B' circuit, specifically an open or short to power, which can affect transmission operation.

2. What are the common symptoms of code P0977 on a 2015 GMC Sierra?

Symptoms may include harsh or delayed shifting, failure to shift gears, transmission stuck in one gear, and the illumination of the check engine light.

3. What causes the P0977 code in a 2015 GMC Sierra?

Common causes include a faulty shift solenoid 'B,' damaged wiring or connectors in the solenoid circuit, a shorted or open circuit, or a malfunctioning transmission control module (TCM).

4. Can I drive my 2015 GMC Sierra with a P0977 code?

It’s possible to drive with this code, but it’s not recommended as it can cause further damage to the transmission or lead to unsafe driving conditions.

5. How do I diagnose the P0977 code on a 2015 GMC Sierra?

Diagnosis typically involves scanning for additional codes, inspecting the wiring and connectors for damage, testing the shift solenoid 'B,' and checking the TCM for faults.

6. How do I fix the P0977 code on a 2015 GMC Sierra?

Repairs may include replacing the shift solenoid 'B,' repairing or replacing damaged wiring or connectors, or reprogramming or replacing the TCM if necessary.

7. How much does it cost to repair a P0977 code on a 2015 GMC Sierra?

Repair costs vary but can range from $150 to $400 for solenoid replacement, with higher costs if the wiring or TCM needs repair or replacement.

8. Can a dirty transmission fluid cause a P0977 code in a 2015 GMC Sierra?

While unlikely, dirty or contaminated transmission fluid can lead to solenoid issues, so it’s worth checking and replacing the fluid if needed.

9. Is the P0977 code related to other transmission codes on a 2015 GMC Sierra?

Yes, it may be accompanied by other transmission-related codes indicating further issues with solenoids, circuits, or the TCM.

10. Do I need special tools to fix the P0977 code on a 2015 GMC Sierra?

Yes, tools like an OBDII scanner, multimeter, and potentially transmission-specific tools may be required for diagnosis and repair.

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