P279C Buick 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 Buick 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.
Code P279C Buick Description
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.
What are the Possible Causes of the DTC P279C 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 P279C 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 P279C 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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Frequently Asked Questions about P279C Buick Code
1. What does the OBDII code P279C mean on a Buick?
P279C indicates a "Four Wheel Drive Neutral Range Performance" issue, meaning the system is detecting a problem with the neutral range of the four-wheel-drive transfer case.
2. What are common symptoms of the P279C code on a Buick?
Symptoms can include the four-wheel-drive system not engaging properly, the vehicle being stuck in neutral, warning lights on the dashboard, or issues with drivability.
3. What causes the P279C code to appear?
Common causes include a faulty transfer case shift motor, wiring or connector issues, problems with the four-wheel-drive control module, or mechanical issues within the transfer case.
4. Can driving with the P279C code cause further damage?
Yes, ignoring the P279C code may lead to additional damage to the transfer case or four-wheel-drive system and could cause the vehicle to become undrivable.
5. How can I diagnose the P279C code on my Buick?
Start by scanning the vehicle with an OBDII scanner, inspecting the transfer case shift motor and wiring for damage, and checking for loose or corroded connections.
6. How do you fix the P279C code on a Buick?
Repairs may involve replacing the transfer case shift motor, repairing damaged wiring, updating or reprogramming the four-wheel-drive control module, or addressing mechanical issues in the transfer case.
7. Is the P279C code specific to Buick vehicles?
No, while it can appear on Buick models with four-wheel-drive systems, the code is not specific to Buick and may also occur in other makes and models.
8. What tools are needed to troubleshoot the P279C code?
An OBDII scanner, a multimeter for testing electrical connections, and possibly specialty tools for accessing and repairing the transfer case components.
9. Can I fix the P279C code myself, or do I need a mechanic?
If you have the tools and knowledge to diagnose and repair four-wheel-drive systems, you can attempt the fix. However, more complex issues may require professional assistance.
10. How much does it cost to repair the P279C code on a Buick?
The repair cost can vary widely, from $150 for minor wiring fixes to over $1,000 if the transfer case or shift motor needs replacement.
Discuss the causes and fixes for P279C Buick OBDII Code
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