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Engine-Codes – GMC – P0974 GMC

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

Quick Answer

When the OBD-II trouble code P0974 appears on a GMC vehicle, it indicates a problem with the Shift Solenoid Valve 1 Control Circuit registering a high voltage. Common causes include Faulty shift solenoid valve, Wiring or connector issues in the shift solenoid circuit, Low transmission fluid levels or dirty fluid. 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 GMC indicates Shift Solenoid Valve 1 Control Circuit High Voltage.
Common causes
Common causes include Faulty shift solenoid valve, Wiring or connector issues in the shift solenoid circuit, Low transmission fluid levels or dirty fluid.
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.
What is this?
Table of contents Created and updated by William Orellana on Aug 19, 2024
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Code P0974 GMC Description

When the OBD-II trouble code P0974 appears on a GMC vehicle, it indicates a problem with the Shift Solenoid Valve 1 Control Circuit registering a high voltage. The shift solenoid valve is responsible for controlling the flow of transmission fluid to engage gears within the transmission. When the control circuit detects a voltage higher than the specified range, it can lead to issues with shifting gears smoothly or could potentially cause the transmission to fail to engage gears altogether. This can result in poor vehicle performance, reduced fuel efficiency, and potential damage to the transmission system if left unaddressed.

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

Common Causes of P0974 GMC

  1. Faulty shift solenoid valve
  2. Wiring or connector issues in the shift solenoid circuit
  3. Low transmission fluid levels or dirty fluid
  4. Electrical problems within the transmission control module
  5. Mechanical issues within the transmission system

Symptoms of P0974 GMC

  1. Harsh or delayed shifting between gears
  2. Transmission slipping or difficulty engaging gears
  3. Illuminated Check Engine Light
  4. Decreased fuel efficiency
  5. Transmission overheating

How to Fix P0974 GMC

  1. Begin by conducting a thorough inspection of the shift solenoid valve and its wiring harness for any signs of damage or corrosion.
  2. Test the shift solenoid valve and the control circuit using a multimeter to check for proper voltage levels.
  3. If the shift solenoid valve is faulty, replace it with a new one and ensure proper installation.
  4. Inspect and repair any damaged wiring or connectors in the circuit.
  5. Clear the trouble code from the vehicle's computer system and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0974 GMC

The cost of repairing a P0974 GMC trouble code can vary depending on the specific cause of the issue and the labor rates in your area. Generally, the parts required for this repair, such as a new shift solenoid valve, can range from $100 to $300. Additionally, labor costs can add another $100 to $200, bringing the total repair cost to approximately $200 to $500. It's important to note that these estimates are rough figures, and actual costs may differ based on various factors.

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Information for Specific GMC Models

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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