AutoCodes – Buick – P279A Buick

P279A Buick Code - Four Wheel Drive High Range Performance

Quick Answer

The Engine Control Module (ECM) uses the following two ways to determine if the transfer case is in 4WD Low, 4WD High, or Neutral. Common causes include Reprogram Engine Control Module (ECM), Faulty Engine Control Module, Engine Control Module harness is open or shorted. 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: P279A Buick indicates Four Wheel Drive High Range Performance.
Common causes: Common causes include Reprogram Engine Control Module (ECM), Faulty Engine Control Module, Engine Control Module harness is open or shorted.
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 896

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 Aug 29, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P279A Buick Description

The Engine Control Module (ECM) uses the following two ways to determine if the transfer case is in 4WD Low, 4WD High, or Neutral.
1. The first way is to compare the transmission output speed sensor to the transfer case output speed sensor in order to calculate the transfer case range.
2. The second way is to use a LAN message sent by the transfer case shift control module to the ECM.
The ECM uses this message to determine motor torque required and transmission shifting.
The internal fault detection is handled inside the control module. No external circuit diagnosis is involved.
If the first way and second way of determining transfer case range do not match while in 4WD Low, 4WD High or Neutral, then the Diagnostic Trouble Code (DTC) is set.

OBDII Code P279A Buick - Four Wheel Drive High Range Performance - AutoCodes.com — P279A Buick Code - Four Wheel Drive High Range Performance

What does this mean?

What are the Possible Causes of the DTC P279A Buick?

Reprogram Engine Control Module (ECM)
Faulty Engine Control Module
Engine Control Module harness is open or shorted
Engine Control Module circuit poor electrical connection
Transmission internal mechanical problems

How to Fix the DTC P279A 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 P279A 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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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 P279A Buick Code

1. What are the common symptoms of OBDII code P279A in a Buick related to Four Wheel Drive High Range Performance?

- Common symptoms include difficulty engaging or disengaging four-wheel drive, issues with shifting between high and low range, and a warning light on the dashboard.

2. What are the possible causes of OBDII code P279A in a Buick related to Four Wheel Drive High Range Performance?

- Possible causes include a malfunctioning transfer case motor, faulty wiring or connectors, low transfer case fluid levels, or mechanical issues within the transfer case system.

3. How can I diagnose the OBDII code P279A in my Buick related to Four Wheel Drive High Range Performance?

- A diagnostic scan tool can help retrieve the specific code and provide insight into the issue. Additionally, a visual inspection of the transfer case components and electrical connections can help identify any visible problems.

4. What are some repair tips for addressing OBDII code P279A in a Buick related to Four Wheel Drive High Range Performance?

- Begin by checking the transfer case fluid level and condition, ensuring all electrical connections are secure, and inspecting the transfer case motor for any signs of damage. If necessary, consider replacing the transfer case motor or addressing any wiring issues.

5. Can I continue driving my Buick with OBDII code P279A related to Four Wheel Drive High Range Performance?

- It is not recommended to continue driving with this code active, as it may lead to further damage to the transfer case system. It's best to address the issue promptly to avoid potential safety hazards or costly repairs.

6. Is it possible to reset the OBDII code P279A in my Buick related to Four Wheel Drive High Range Performance?

- While clearing the code with a diagnostic scan tool may temporarily turn off the warning light, the underlying issue causing the code will likely persist. It's essential to diagnose and address the root cause of the problem.

7. How much does it typically cost to repair OBDII code P279A in a Buick related to Four Wheel Drive High Range Performance?

- The cost of repairs can vary depending on the specific issue causing the code and the extent of the repairs needed. It's advisable to consult a mechanic or dealership for a more accurate estimate based on your vehicle's condition.

8. Will OBDII code P279A in a Buick related to Four Wheel Drive High Range Performance affect the vehicle's drivability?

- In some cases, the vehicle may still be operable with this code present, but there may be issues with engaging four-wheel drive or shifting between high and low range. It's best to address the problem promptly to ensure optimal drivability.

9. How long does it typically take to repair OBDII code P279A in a Buick related to Four Wheel Drive High Range Performance?

- The repair time can vary depending on the complexity of the issue and the availability of parts. Some repairs may be completed within a few hours, while more extensive repairs could take longer. It's advisable to consult with a mechanic for a more accurate timeline.

10. Are there any preventative measures I can take to avoid OBDII code P279A in my Buick related to Four Wheel Drive High Range Performance?

- Regularly inspecting and maintaining the transfer case system, including checking fluid levels, ensuring proper electrical connections, and addressing any issues promptly, can help prevent the occurrence of this code.