P279B 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado 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.
Code P279B 2018 Chevrolet Silverado 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 P279B 2018 Chevrolet Silverado?
- 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 2018 Chevrolet Silverado?
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 2018 Chevrolet Silverado 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 P279B 2018 Chevrolet Silverado Code
1. What does the OBDII code P279B mean on a 2018 Chevrolet Silverado?
P279B indicates a Four-Wheel Drive Low Range Performance issue, meaning the system is not engaging or operating as expected in 4WD low mode.
2. What are common symptoms of the P279B code in a Chevrolet Silverado?
Symptoms may include the 4WD low range not engaging, a 4WD warning light on the dashboard, reduced off-road capability, or drivability issues in low-range mode.
3. What causes the P279B code to appear on a 2018 Silverado?
Common causes include a malfunctioning transfer case motor, damaged wiring or connectors, a faulty 4WD control module, or low or contaminated transfer case fluid.
4. How can I diagnose the P279B code on my Silverado?
Start by scanning the vehicle with an OBDII scanner to confirm the code. Then inspect the transfer case motor, wiring, connectors, and fluid level for any issues. Further testing of the 4WD control module may be necessary.
5. Can I still drive my Silverado with a P279B code?
Yes, but you may lose access to 4WD low functionality, which could limit off-road or towing performance. It’s best to address the issue promptly to avoid further damage.
6. How do I fix the P279B code on a 2018 Chevrolet Silverado?
Repairs may involve replacing the transfer case motor, repairing damaged wiring, updating or reprogramming the 4WD control module, or servicing the transfer case fluid.
7. What tools are needed to troubleshoot the P279B code?
You’ll need an OBDII scanner, a multimeter for electrical testing, and basic tools to inspect and replace components like the transfer case motor.
8. How much does it cost to fix the P279B code on a Silverado?
Repair costs vary but typically range from $150 to $600 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, low or contaminated transfer case fluid can cause 4WD low range issues, triggering the P279B code. Always check and maintain proper fluid levels.
10. Is it necessary to reprogram the 4WD control module for the P279B code?
In some cases, reprogramming or updating the 4WD control module may resolve the issue, especially if it’s related to software glitches. Consult a professional if unsure.
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