AutoCodes – GMC – P2809 2018 GMC Sierra

P2809 2018 GMC Sierra Code - Transmission Control Solenoid Valve 7 Stuck On

Quick Answer

The Transmission Control Module (TCM) uses the vehicle speed signal to determine the actual gear position (1st, 2nd, 3rd, 4th. Common causes include Faulty Transfer Case Shift Control Switch, Transfer Case Shift Control Switch harness is open or shorted, Transfer Case Shift Control Switch 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: P2809 2018 GMC Sierra indicates Transmission Control Solenoid Valve 7 Stuck On.
Common causes: Common causes include Faulty Transfer Case Shift Control Switch, Transfer Case Shift Control Switch harness is open or shorted, Transfer Case Shift Control Switch 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 280

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
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Code P2809 2018 GMC Sierra Description

The Transmission Control Module (TCM) uses the vehicle speed signal to determine the actual gear position (1st, 2nd, 3rd, 4th. 5th or 6th gear). The solenoid valve controls the flow of transmission fluid to the hydraulic valve that controls the system pressure in the transmission. Then the TCM compares the actual gear with the shift schedule in the TCM memory to detect shift solenoid valves and valve body mechanical problems.

OBDII Code P2809 2018 GMC Sierra - Transmission Control Solenoid Valve 7 Stuck On - AutoCodes.com — P2809 2018 GMC Sierra Code - Transmission Control Solenoid Valve 7 Stuck On

What does this mean?

What are the Possible Causes of the DTC P2809 2018 GMC Sierra?

Faulty Transfer Case Shift Control Switch
Transfer Case Shift Control Switch harness is open or shorted
Transfer Case Shift Control Switch circuit poor electrical connection

How to Fix the DTC P2809 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 P2809 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 P2809 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.

Frequently Asked Questions about P2809 2018 GMC Sierra Code

1. What does the OBDII code P2809 mean on a 2018 GMC Sierra?

The code P2809 indicates that the Transmission Control Module (TCM) has detected that solenoid valve 7 is stuck in the "on" position, causing issues with gear shifting or transmission performance.

2. What are the common symptoms of a P2809 code on a 2018 GMC Sierra?

Symptoms may include harsh or delayed shifting, transmission slipping, reduced fuel efficiency, or the vehicle going into limp mode.

3. What causes the P2809 code to appear on a 2018 GMC Sierra?

Common causes include a malfunctioning transmission solenoid, wiring issues like damaged or corroded connectors, or problems with the Transmission Control Module (TCM).

4. Can I still drive my 2018 GMC Sierra with a P2809 code?

While the vehicle may still be drivable, continuing to drive with this code can cause further damage to the transmission. Itâ€™s best to address the issue as soon as possible.

5. How do I diagnose the P2809 code on my 2018 GMC Sierra?

Diagnosis involves checking the solenoid valve 7 for proper operation, inspecting the wiring and connectors for damage, and using a scan tool to monitor TCM data and solenoid performance.

6. How can I fix the P2809 code on my 2018 GMC Sierra?

Repairs may include replacing the faulty solenoid, repairing or replacing damaged wiring, cleaning corroded connectors, or reprogramming or replacing the TCM.

7. How much does it cost to fix a P2809 code on a 2018 GMC Sierra?

Costs vary depending on the repair, but replacing a transmission solenoid typically ranges from $150 to $400, while TCM replacement can cost $500 to $1,000 or more.

8. Can low transmission fluid cause a P2809 code on a 2018 GMC Sierra?

Yes, low or contaminated transmission fluid can affect solenoid operation and may trigger this code. Checking and replacing the fluid is a good first step.

9. Will clearing the P2809 code fix the problem on my 2018 GMC Sierra?

Clearing the code may temporarily remove the warning, but the underlying issue must be fixed to prevent the code from returning and avoid potential transmission damage.

10. Is a P2809 code a common issue for the 2018 GMC Sierra?

Itâ€™s not a widespread issue but can occur due to wear and tear, especially if the vehicle has high mileage or a history of transmission problems. Regular maintenance can help prevent it.