Downhill Assist Control and Stability Systems in the 2025 4Runner

[Administrator]

The 2025 6th Gen 4Runner is equipped with several electronic driver support systems that enhance control during off-road and on-road driving. This includes:

• DAC (Downhill Assist Control): Maintains a slow, controlled speed on steep descents without driver input on the brake pedal
• VSC (Vehicle Stability Control): Helps reduce skidding during sudden maneuvers by managing engine power and braking
• TRAC (Traction Control): Prevents wheelspin on slippery surfaces by adjusting throttle and selectively applying brakes

These systems work independently and together to improve vehicle stability and driver confidence across a variety of driving conditions.

Overview of DAC, VSC, TRAC, and More
(Reference: 2025 Owner’s Manual, pg. 428–433)
Link to Owners Manual: https://trail4runner.com/wp-content/uploads/2025/03/2025-4runner-owners-manual.pdf

Downhill Assist Control (DAC)​

DAC helps maintain a controlled descent on steep declines by automatically modulating brake pressure to hold a steady, low speed.

It operates when:

• Transfer case is in 4H
• Vehicle speed is under 18 mph
• The shift lever is not in Park
• The DAC system is activated using the DAC/CRAWL switch

Set speed can be adjusted using the mode select dial. Operating range is approximately 3 to 18 mph. The multi-information display will show the set speed.

Indicators and behavior:

• The DAC system indicator illuminates when active
• Slip indicator flashes during operation
• A chime and vibration through the brake pedal or steering may be noticed—these are normal
• If the brake actuator overheats, the system will pause and flash a warning

Conditions that cancel or disable DAC:

• Vehicle speed exceeds 18 mph
• Brake system overheats
• Front-wheel drive control switch is not in 4H
• Gear selector is in Park

Vehicle Stability Control (VSC)​

VSC helps reduce skidding when cornering or swerving on slippery surfaces by managing engine output and brake force at each wheel.
Enhanced VSC adds coordination with Electric Power Steering (EPS) to help maintain directional control.

Traction Control (TRAC)​

TRAC prevents wheelspin during acceleration on low-traction surfaces like snow or loose dirt by adjusting engine power and applying brakes to specific wheels.
It can be temporarily disabled to aid in vehicle recovery when stuck.

To turn off TRAC:

• Briefly press the VSC OFF button
  To disable both TRAC and VSC:
• Hold the button for more than 3 seconds

“Traction Control Turned OFF” will appear in the multi-information display.

Additional Support Systems​

• Trailer Sway Control: Applies braking selectively and reduces engine torque if trailer sway is detected
• Hill-Start Assist Control: Temporarily holds brake pressure to prevent rollback on inclines
• ABS & Brake Assist: Enhance stopping ability during emergency braking or low-traction conditions
• Adaptive Variable Suspension (AVS) (if equipped): Adjusts damping force based on terrain and driving input

2025 4Runner Downhill Assist and Stability Control Diagram​

The Owner’s Manual (pages 428–431) includes DAC activation steps, system status indicators, and layout of key driving support systems.