AutoCodes – Cadillac – P279C Cadillac

P279C Cadillac Code - Four Wheel Drive Neutral 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: P279C Cadillac indicates Four Wheel Drive Neutral 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 1,065

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 P279C 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 P279C Cadillac - Four Wheel Drive Neutral Range Performance - AutoCodes.com — P279C Cadillac Code - Four Wheel Drive Neutral Range Performance

What does this mean?

What are the Possible Causes of the DTC P279C 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 P279C 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 P279C 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 P279C Cadillac Code

1. What are the common symptoms of OBDII code P279C Cadillac (Four Wheel Drive Neutral Range Performance)?

The common symptoms include difficulty shifting gears, the vehicle getting stuck in neutral, and the four-wheel-drive system not engaging properly.

2. What are the possible causes of OBDII code P279C Cadillac (Four Wheel Drive Neutral Range Performance)?

Possible causes include a malfunctioning transfer case control module, issues with the four-wheel-drive actuator, faulty wiring or connections, or a problem with the transfer case itself.

3. How can I diagnose OBDII code P279C Cadillac (Four Wheel Drive Neutral Range Performance)?

Diagnosis involves using a professional OBDII scanner to retrieve the trouble codes, checking the transfer case control module for any stored codes, inspecting the wiring and connections related to the four-wheel-drive system, and performing a visual inspection of the transfer case components.

4. Can I still drive my vehicle with OBDII code P279C Cadillac (Four Wheel Drive Neutral Range Performance)?

It is not recommended to drive your vehicle with this code present, as it may lead to further damage to the four-wheel-drive system or transmission. It is best to have the issue diagnosed and repaired as soon as possible.

5. How can I repair OBDII code P279C Cadillac (Four Wheel Drive Neutral Range Performance)?

Repairing this code may involve replacing the transfer case control module, repairing or replacing the four-wheel-drive actuator, checking and repairing any faulty wiring or connections, or diagnosing and repairing any issues with the transfer case.

6. Is OBDII code P279C Cadillac (Four Wheel Drive Neutral Range Performance) a common issue?

This code is not as common as some other OBDII codes, but it can occur in Cadillac vehicles with four-wheel-drive systems. Proper maintenance and timely repairs can help prevent this issue.

7. How much does it cost to fix OBDII code P279C Cadillac (Four Wheel Drive Neutral Range Performance)?

The cost of fixing this code can vary depending on the exact cause of the issue, the labor rates in your area, and whether any parts need to be replaced. It is recommended to get a diagnosis from a professional mechanic to determine the cost.

8. Can a DIY enthusiast repair OBDII code P279C Cadillac (Four Wheel Drive Neutral Range Performance)?

While some aspects of diagnosing and repairing this code may be possible for DIY enthusiasts with the right tools and knowledge, it is recommended to consult a professional mechanic for accurate diagnosis and proper repair to avoid further damage.

9. Will OBDII code P279C Cadillac (Four Wheel Drive Neutral Range Performance) cause damage if left untreated?

Leaving this code untreated can potentially cause damage to the four-wheel-drive system, transmission, or other related components. It is best to address the issue promptly to prevent further damage.

10. How long does it typically take to repair OBDII code P279C Cadillac (Four Wheel Drive Neutral Range Performance)?

The repair time for this code can vary depending on the exact cause of the issue, the availability of parts, and the workload of the repair shop. It is advisable to consult with the mechanic performing the repair for a more accurate time estimate.