AutoCodes – Cadillac – P279B Cadillac

P279B Cadillac Code - Four Wheel Drive Low 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: P279B Cadillac indicates Four Wheel Drive Low 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 905

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 P279B Cadillac 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 P279B Cadillac - Four Wheel Drive Low Range Performance - AutoCodes.com — P279B Cadillac Code - Four Wheel Drive Low Range Performance

What does this mean?

What are the Possible Causes of the DTC P279B Cadillac?

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 P279B Cadillac?

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 P279B Cadillac 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 P279B Cadillac Code

1. What does the OBDII code P279B mean on a Cadillac?

The P279B code indicates an issue with the Four Wheel Drive (4WD) Low Range Performance, suggesting a problem with the 4WD system engaging or functioning properly.

2. What are the common symptoms of the P279B code on a Cadillac?

Symptoms may include the 4WD system failing to engage low range, warning lights on the dashboard, and reduced off-road performance.

3. What causes the P279B code to appear on a Cadillac?

Common causes include a faulty transfer case motor, damaged wiring or connectors, a malfunctioning 4WD control module, or low transfer case fluid.

4. Can I drive my Cadillac with the P279B code?

Yes, but you may experience limited 4WD capability, especially in low-range mode. Itâ€™s best to address the issue promptly to avoid further damage.

5. How do I diagnose the P279B code on my Cadillac?

Diagnosis involves scanning for codes, inspecting the transfer case motor and wiring, checking the transfer case fluid level, and testing the 4WD control module.

6. How can I fix the P279B code on my Cadillac?

Repairs may include replacing the transfer case motor, repairing damaged wiring, refilling or replacing transfer case fluid, or reprogramming or replacing the 4WD control module.

7. Is the P279B code related to other 4WD system issues?

Yes, the P279B code may occur alongside other 4WD-related codes, indicating a broader system issue requiring further inspection.

8. How much does it cost to fix the P279B code on a Cadillac?

Repair costs vary but typically range from $150 to $800, depending on whether the issue is with the transfer case motor, wiring, or control module.

9. Can low transfer case fluid cause the P279B code?

Yes, insufficient or contaminated transfer case fluid can prevent the 4WD system from functioning properly and trigger the P279B code.

10. Do I need a professional to fix the P279B code?

While some issues, like checking fluid levels, can be done at home, diagnosing and repairing components like the transfer case motor or control module may require a professional mechanic.