AutoCodes – Buick – P27AA Buick

P27AA Buick Code - Transmission Control Solenoid Valve 4 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: P27AA Buick indicates Transmission Control Solenoid Valve 4 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 376

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 P27AA Buick 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 P27AA Buick - Transmission Control Solenoid Valve 4 Calibration Incorrect - AutoCodes.com — P27AA Buick Code - Transmission Control Solenoid Valve 4 Calibration Incorrect

What does this mean?

What are the Possible Causes of the DTC P27AA Buick?

Solenoid Valve Characterization Reprogramming

How to Fix the DTC P27AA Buick?

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 P27AA Buick 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.

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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 P27AA Buick Code

1. What does the OBDII code P27AA mean on a Buick?

The P27AA code indicates that the Transmission Control Solenoid Valve 4 calibration is incorrect, suggesting an issue with the solenoid's operation or programming in the transmission system.

2. What are the symptoms of a P27AA code on a Buick?

Common symptoms include erratic shifting, transmission slipping, harsh gear engagement, or the transmission staying in one gear.

3. What causes the P27AA code to appear?

Possible causes include a faulty transmission control solenoid, low or dirty transmission fluid, wiring issues, or incorrect programming of the transmission control module (TCM).

4. Can I drive my Buick with a P27AA code?

Driving with a P27AA code is not recommended as it may lead to further transmission damage or unsafe driving conditions. Have the issue diagnosed and repaired promptly.

5. How do I fix the P27AA code on my Buick?

Repairs may involve replacing the faulty solenoid, addressing wiring or connector issues, flushing and replacing the transmission fluid, or reprogramming the TCM.

6. How much does it cost to fix a P27AA code on a Buick?

The cost varies depending on the issue but may range from $200 to $500 for solenoid replacement and up to $1,000 if programming or extensive repairs are needed.

7. Can low transmission fluid cause the P27AA code?

Yes, low or contaminated transmission fluid can affect solenoid operation and trigger the P27AA code. Check and replace the fluid if necessary.

8. Do I need to replace the transmission to fix the P27AA code?

Not necessarily. Most P27AA code cases can be resolved by repairing or replacing the solenoid, fixing wiring issues, or reprogramming the TCM without replacing the entire transmission.

9. What tools are needed to diagnose the P27AA code?

A professional OBDII scanner, multimeter, and possibly a transmission pressure gauge are needed to diagnose the code and pinpoint the issue.

10. Can a software update fix the P27AA code on a Buick?

Yes, in some cases, reprogramming the Transmission Control Module (TCM) with updated software may resolve the calibration issue and clear the P27AA code.