Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer has detected a problem with the low gear in the part of the car that helps it switch between two-wheel and four-wheel drive. It's like when a bicycle chain is on the wrong gear and doesn't work right.
The P279B code indicates that the transfer case, which allows the vehicle to switch between different drive modes (like two-wheel and four-wheel drive), is not functioning correctly in the low gear setting.
The transfer case is responsible for distributing power from the transmission to the front and rear axles. When the vehicle is in low gear, the transfer case should maintain a specific gear ratio. The P279B code is triggered when the powertrain control module (PCM) detects that the actual gear ratio does not match the expected ratio for low gear, indicating a potential mechanical or electronic fault.
• Check Engine Light illuminated
• Difficulty shifting into low gear
• Unusual noises from the transfer case
• Faulty transfer case control module
• Mechanical failure in the transfer case
• Damaged or worn transfer case gears
Transfer Case: A component that transfers power from the transmission to the front and rear axles.
PCM: Powertrain Control Module, the vehicle's computer that manages engine and transmission functions.
• Use an OBD-II scanner to confirm the code.
• Inspect the transfer case for mechanical damage.
• Check the transfer case control module for faults.
• Replace or repair the transfer case gears.
• Reset or replace the transfer case control module.
• Perform a software update on the PCM if available.
• OBD-II scanner
• Wrench set
• Diagnostic software
$500 - $1500
Moderate
• Ford F-150
• Chevrolet Silverado
• Jeep Wrangler
• Regular maintenance of the transfer case
• Avoiding excessive off-road driving
• Checking for leaks and unusual noises regularly
Transmission/Drivetrain Issue
• Avoid using low gear until the issue is resolved.
• Consult a professional mechanic for a thorough inspection.
Check with your vehicle manufacturer, as drivetrain components may be covered under powertrain warranty.
This code has been reported in vehicles with high mileage or those frequently used in off-road conditions.
Moderate – While the vehicle may still be drivable, using low gear can lead to further damage.
Driving with a malfunctioning transfer case can affect vehicle handling and safety. Address this issue promptly.
• Vehicle on a lift to inspect the transfer case
• Driving in a controlled environment to test gear shifts
The transfer case is located underneath the vehicle, typically near the center, connected to the transmission and driveshafts.
Q: Can I drive with a P279B code?
A: It's not recommended to drive in low gear until the issue is fixed, as it may cause further damage.
Q: What happens if I ignore this code?
A: Ignoring the code can lead to more severe drivetrain damage and costly repairs.
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