AutoCodes – GMC – P27AD 2018 GMC Sierra

P27AD 2018 GMC Sierra Code - Transmission Control Solenoid Valve 7 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: P27AD 2018 GMC Sierra indicates Transmission Control Solenoid Valve 7 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 178

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 P27AD 2018 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 P27AD 2018 GMC Sierra - Transmission Control Solenoid Valve 7 Calibration Incorrect - AutoCodes.com — P27AD 2018 GMC Sierra Code - Transmission Control Solenoid Valve 7 Calibration Incorrect

What does this mean?

What are the Possible Causes of the DTC P27AD 2018 GMC Sierra?

Solenoid Valve Characterization Reprogramming

How to Fix the DTC P27AD 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 P27AD 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 P27AD 2018 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 P27AD 2018 GMC Sierra Code

1. What does the OBDII code P27AD on a 2018 GMC Sierra indicate?

The code P27AD indicates that there is an issue with Transmission Control Solenoid Valve 7, specifically that its calibration is incorrect. This solenoid helps manage the flow of transmission fluid and shifting gears.

2. What are common symptoms of the P27AD code in a 2018 GMC Sierra?

Symptoms can include erratic shifting, the transmission slipping, the vehicle going into limp mode, or a check engine light. You might also notice decreased fuel efficiency or the transmission failing to shift properly.

3. What causes the P27AD code to appear on a 2018 GMC Sierra?

This code is triggered by various factors, such as a faulty transmission control solenoid, incorrect installation of the solenoid, electrical issues like poor wiring connections, or a faulty transmission control module.

4. How can I fix the P27AD code on my 2018 GMC Sierra?

To fix this issue, inspect and possibly replace the transmission control solenoid valve 7, check and repair any faulty wiring or connectors, and ensure the solenoid is calibrated correctly according to manufacturer specifications.

5. Is it safe to drive a 2018 GMC Sierra with the P27AD code?

Driving with this code is not recommended as it can lead to further damage to the transmission. Itâ€™s advisable to address the issue promptly to avoid potential safety risks and more costly repairs.

6. How do I diagnose the P27AD code on a 2018 GMC Sierra?

Diagnosis involves using a scan tool to confirm the presence of the P27AD code, visually inspecting the transmission control solenoid and associated wiring, and testing the solenoid with a multimeter to check for electrical faults.

7. What tools are required to resolve the P27AD code in a 2018 GMC Sierra?

You will need a diagnostic scan tool, a multimeter for electrical testing, and basic hand tools for removing and replacing components. A proper solenoid calibration might require specific software and tools provided by the manufacturer.

8. Can a faulty transmission control module cause the P27AD code on a 2018 GMC Sierra?

Yes, a faulty transmission control module can cause this code. If the module fails to operate correctly, it may not control the solenoid accurately, leading to calibration issues.

9. What is the role of Transmission Control Solenoid Valve 7 in a 2018 GMC Sierra?

This solenoid valve helps control the flow of hydraulic fluid to different transmission clutches, which is crucial for proper gear selection and shifting performance in the vehicle. It ensures the transmission operates smoothly by engaging the correct gear.