AutoCodes – GMC – P27AC 2015 GMC Sierra

P27AC 2015 GMC Sierra Code - Transmission Control Solenoid Valve 6 Calibration Incorrect

Quick Answer

The Transmission Control Solenoid Valve 1, 2, 3, 4, 5, 6, 7 have a unique current versus oil pressure characteristic that is used to properly upshift or downshift the transmission. Common causes include Solenoid Valve Characterization Reprogramming. 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: P27AC 2015 GMC Sierra indicates Transmission Control Solenoid Valve 6 Calibration Incorrect.
Common causes: Common causes include Solenoid Valve Characterization Reprogramming.
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 160

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 Sep 22, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P27AC 2015 GMC Sierra Description

The Transmission Control Solenoid Valve 1, 2, 3, 4, 5, 6, 7 have a unique current versus oil pressure characteristic that is used to properly upshift or downshift the transmission. The data for each solenoid valve is programmed into the Transmission Control Module (TCM). The Diagnostic Trouble Code (DTC) will be set when the Transmission Control Solenoid Valve Calibration Data has not been programmed.

OBDII Code P27AC 2015 GMC Sierra - Transmission Control Solenoid Valve 6 Calibration Incorrect - AutoCodes.com — P27AC 2015 GMC Sierra Code - Transmission Control Solenoid Valve 6 Calibration Incorrect

What does this mean?

What are the Possible Causes of the DTC P27AC 2015 GMC Sierra?

Solenoid Valve Characterization Reprogramming

How to Fix the DTC P27AC 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 P27AC 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 P27AC 2015 GMC Sierra code?

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Need Help with the 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 P27AC 2015 GMC Sierra Code

What does OBDII code P27AC mean for a 2015 GMC Sierra?

Code P27AC indicates that the Transmission Control Module (TCM) has detected an issue with the calibration of solenoid valve 6 in the transmission.

What are the common symptoms of code P27AC?

Symptoms may include erratic shifting, transmission slipping, poor acceleration, and the illumination of the check engine light.

What causes code P27AC in a 2015 GMC Sierra?

Common causes include a malfunctioning transmission control solenoid, outdated TCM software, damaged wiring or connectors, or internal transmission wear.

Can I drive my GMC Sierra with a P27AC code?

Driving with this code is not recommended as it can lead to further transmission damage or unsafe driving conditions if the issue worsens.

How is the P27AC code diagnosed?

A technician will use a scan tool to confirm the code, inspect the transmission solenoid and wiring, and may perform a TCM software update or internal transmission inspection.

What repairs are typically needed to fix code P27AC?

Repairs may include replacing the faulty solenoid, repairing or replacing damaged wiring, updating or reprogramming the TCM, or performing internal transmission repairs.

How much does it cost to fix a P27AC code?

Repair costs can range from $200 to $1,500 depending on the specific issue, with solenoid replacement or TCM reprogramming on the lower end and transmission repairs on the higher end.

Can a failing transmission solenoid cause other problems?

Yes, a faulty solenoid can lead to poor transmission performance, overheating, or further internal damage if not addressed promptly.

Will clearing the P27AC code fix the problem?

Clearing the code may turn off the check engine light temporarily, but the underlying issue must be resolved to prevent the code from returning.

Is a TCM software update necessary to fix the P27AC code?

In some cases, a TCM software update can resolve calibration issues without requiring hardware replacement, but this depends on the specific cause of the code.