2024+ 4th Gen Tacoma - Downhill Assist Control (DAC)

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Downhill Assist Control (DAC) helps prevent excessive speed on steep downhill slopes. DAC manages both throttle and braking automatically to maintain a steady, driver-selected speed when descending steep grades, allowing you to focus on steering through challenging terrain. It operates when the transfer case is in 4H mode and vehicle speed is under 18 mph, giving you control over how aggressively or conservatively you navigate downhill sections.

(Reference: Owner's Manual, pg. 418-419)

Downhill Assist Control, DAC System, Hill Descent, Automatic Speed Control​

DAC is an electronic descent control system that you can adjust within a range of about 3 mph (4 km/h) to 18 mph (30 km/h). It's ideal for forest service roads, steep boat ramps, or trail sections where you need controlled descent speed without constant brake pedal modulation.

Toyota-Specific Context:
DAC is part of Toyota's off-road assistance suite, distinct from Crawl Control (which manages both ascents and descents in 4L). DAC works specifically in 4H for moderate off-road descents.

System Components​

DAC/CRAWL Switch

• Shared button that activates either DAC (in 4H) or Crawl Control (in 4L)
• Located on the center console near the transfer case controls
• Indicator light shows system status (solid = active, flashing = transitioning or alert)

Mode Select Switch

• Dial/switch used to adjust the target descent speed
• Increases or decreases speed in increments
• Selected speed displays on the multi-information display

Multi-Information Display

• Shows current DAC status (on/off)
• Displays selected descent speed
• Indicates system alerts or deactivation

Related Indicators During Operation

• Downhill assist control system indicator (solid when active)
• Slip indicator (flashes during DAC operation - this is normal)
• Stop lights/high mounted stop lights (illuminate during active braking)
• Audible sounds may occur during system operation (brake actuation - not a malfunction)

How to Activate Downhill Assist Control​

Prerequisites​

Vehicle Requirements:

• Transfer case in 4H mode (DAC will not activate in 2H or 4L)
• Vehicle speed under 18 mph (30 km/h)
• Automatic transmission: Shift lever in any position except P
• Manual transmission: Clutch pedal NOT depressed, shift lever not in N (N will work but flash a warning)

Recommended Before Activation:

• Select a lower shift range for more effective engine braking assistance
• Can be used with TOW HAUL mode ON or OFF
• Can be used with Multi-Terrain Select (MTS) ON or OFF
• Can be used with Drive Mode Select settings

Activation Procedure​

Step 1: Press the DAC/CRAWL Switch

When the DAC/CRAWL switch indicator is OFF:

1. Press the "DAC/CRAWL" switch once
2. The downhill assist control system indicator will come on (solid light)
3. DAC is now active and will begin managing descent speed

What You'll Notice During Activation:

• Slip indicator begins flashing (normal operation)
• Stop lights illuminate when DAC applies brakes
• You may hear brake actuation sounds (this does not indicate a malfunction)
• Vehicle descent speed stabilizes at the default setting

Adjusting Descent Speed​

Once DAC is active, you control how fast you descend:

Using the Mode Select Switch:

Turn the mode select switch to:

• Increase speed: Rotate one direction (vehicle descends faster)
• Decrease speed: Rotate opposite direction (vehicle descends slower)

Speed Range:

• Minimum: About 3 mph (4 km/h)
• Maximum: About 18 mph (30 km/h)

Display:
The multi-information display shows your selected speed in real-time.

Toyota Off-Road Tip:
Start with a lower speed setting (closer to 3 mph) when first encountering a steep descent. You can always increase speed if conditions allow. It's easier and safer to speed up than to slow down mid-descent on loose or technical terrain. For rocky sections, slower speeds (3-5 mph) give you more time to pick your line and react to obstacles.

How to Deactivate DAC​

Method 1: Manual Deactivation (DAC/CRAWL Switch ON)

When the "DAC/CRAWL" switch indicator is illuminated (system is ON):

1. Press the "DAC/CRAWL" switch again
2. The downhill assist control system indicator will begin flashing (system is transitioning OFF)
3. Indicator turns off completely when system is fully deactivated

During the Transition (Flashing):

• System gradually reduces braking assistance
• You can press the switch again to reactivate before it fully turns off

Method 2: Automatic Deactivation

DAC will automatically disengage if:

• The front-wheel drive control switch is changed to a position other than "4H"
• The shift lever is in P (Vehicles with Automatic transmission)
• The clutch pedal is depressed (vehicles with manual transmission)
• The vehicle speed exceeds about 18 mph (30 km/h)
• The brake system overheats

The indicator will flash and DAC will not operate in these situations.

Understanding DAC Indicator States​

Solid Light (System Active)​

• DAC is fully operational
• Maintaining selected descent speed
• System applying throttle and brakes as needed
• Slip indicator will flash simultaneously (normal)

Flashing Light (Transitioning or Alert)​

Flashing with No Operation (System Disabled):

This occurs when:

• The front-wheel drive control switch is changed to a position other than "4H"
• The shift lever is in P (Vehicles with Automatic transmission)
• The clutch pedal is depressed (vehicles with manual transmission)
• The vehicle speed exceeds about 18 mph (30 km/h)
• The brake system overheats

DAC will not function until the condition is corrected (e.g., return to 4H, slow below 18 mph, take transmission out of P).

Flashing but System Still Operating (Alert):

This occurs when:

• The shift lever is in N
• The "DAC/CRAWL" switch is pressed while the "DAC/CRAWL" switch indicator illuminates (system gradually ceases operation)

The system will continue to work but is alerting you to a non-ideal condition.

Off (No Light)​

• DAC is fully deactivated
• No descent control active
• Standard vehicle braking and throttle control

Integration with Other Toyota 4WD Systems​

DAC + Multi-Terrain Select (MTS)​

• DAC can operate with MTS ON or OFF
• When using both together, MTS manages wheel slip characteristics while DAC manages overall descent speed
• Recommended combination: DAC + MTS "Rock" or "Rock & Dirt" mode for maximum traction control on steep, loose descents

DAC + TOW HAUL Mode​

• DAC works with TOW HAUL mode engaged
• TOW HAUL provides more aggressive engine braking which complements DAC
• Useful when descending with a trailer attached

DAC + Drive Mode Select​

• Normal, ECO, Sport modes all compatible with DAC
• System operates identically regardless of drive mode

DAC vs. Crawl Control​

When to Use DAC (4H):

• Moderate descents on forest service roads, fire roads
• Steep boat ramps
• Downhill sections of maintained trails
• Speed range: 3-18 mph

When to Use Crawl Control (4L):

• Extreme technical terrain requiring maximum control
• Very steep grades where 4L gear reduction is needed
• Both uphill AND downhill crawling
• Speed range: Much slower (1-5 settings, under 5 mph)

Cannot Use Both Simultaneously:
The DAC/CRAWL switch activates DAC in 4H, Crawl Control in 4L. Switching between 4H and 4L changes which system is available.

Continuous Operation and Overheat Protection​

Brake Actuator Overheat​

This may cause the brake actuator to overheat. In this case, the downhill assist control system will stop operating, a buzzer will sound and the downhill assist control system indicator will flash.

When Overheating Occurs:

• DAC automatically shuts down
• Buzzer sounds
• DAC indicator flashes as warning
• You must manually control descent using brake pedal

Preventing Overheats:

1. Use Lower Shift Ranges: Manually select a lower gear (automatic) or shift to lower gear (manual) to increase engine braking assistance
2. Limit Continuous Use: On extremely long descents, deactivate DAC periodically to let brakes cool
3. Adjust Speed Higher When Possible: If terrain allows, higher DAC speeds require less aggressive braking
4. Combine with Engine Braking: The more engine braking you have (lower gear, TOW HAUL mode), the less DAC relies on brake actuation

Recovery from Overheat:

• Stop vehicle safely and allow brake system to cool
• Do not continue descent until brakes cool (potential brake fade)
• Typical cool-down: 5-10 minutes depending on ambient temperature
• After cooling, DAC can be reactivated normally

Optimizing Shift Range Selection​

Automatic Transmission:

• DAC operates in any forward shift position (D, S mode positions)
• Recommended: Select a lower shift range (S4, S3, S2) for better engine braking
• Lower ranges reduce brake actuator workload, improving effectiveness and reducing overheat risk

Manual Transmission:

• DAC operates when shift lever is not in N and clutch is released
• Recommended: Select 2nd or 3rd gear for moderate descents
• Avoid using clutch during DAC operation (depressing clutch disables DAC)

Toyota 4x4 Best Practice:
Before starting descent:

1. Shift to 4H
2. Select appropriate lower gear (2nd or 3rd gear, or S3/S4 range)
3. Activate DAC
4. Adjust speed with mode select switch
5. Allow DAC to manage throttle/brake, you focus on steering

Typical DAC Scenarios​

Scenario 1: Steep Dirt Road Descent​

Terrain: Loose dirt, moderate grade, winding

Setup:

• 4H mode
• Automatic: S4 range
• DAC speed: 5-8 mph
• MTS: "Loose Rock" mode

Why This Works: Moderate speed gives time to navigate corners while maintaining momentum. MTS "Loose Rock" allows controlled wheel slip without losing traction.

Scenario 2: Rocky Technical Trail​

Terrain: Large embedded rocks, steep grade, slow speeds needed for line selection

Setup:

• 4H mode (if grade isn't extreme) OR 4L mode (if very steep - use Crawl Control instead)
• Manual: 2nd gear
• DAC speed: 3-4 mph
• MTS: "Rock" mode

Why This Works: Very slow speeds allow precise steering around obstacles. Lower gear maximizes engine braking support.

Scenario 3: Steep Boat Ramp​

Terrain: Concrete/pavement, very steep grade

Setup:

• 4H mode
• Automatic: S2 or S3 range
• DAC speed: 3-5 mph
• MTS: OFF (paved surface)

Why This Works: Low speed prevents trailer from pushing vehicle. Lower shift range provides maximum engine braking on smooth surface.

Safety Precautions​

WARNING

When using downhill assist control system

Do not rely overmuch on the downhill assist control system. This function does not extend the vehicle's performance limitations. Always thoroughly check the road conditions, and drive safely.

Toyota Master Technician Note:
DAC is a driver assistance feature, not an autonomous descent system. It cannot read terrain ahead or anticipate obstacles. Your responsibility as the driver includes steering, monitoring conditions, and being ready to override the system with brakes or throttle if needed. On extremely steep grades or loose surfaces, DAC may not be able to hold the selected speed perfectly.

Limitations and Important Notes​

What DAC Cannot Do​

• Cannot see ahead: DAC reacts to current speed, not upcoming terrain changes
• Cannot prevent all acceleration: On extremely steep grades, DAC may not fully hold selected speed
• Cannot replace driver steering: You must still navigate around obstacles and choose your line
• Cannot function in 2H or 4L: Only operates in 4H transfer case mode

When NOT to Use DAC​

• On-road driving: Not designed for highway/street use
• Dry pavement descents: Normal braking is more appropriate
• When towing in 4L: Use Crawl Control instead for maximum low-speed control
• If brake system is already hot: Risk of overheat shutdown

Normal Sounds and Sensations​

• Brake actuator sounds: Clicking, whirring, or humming from brake system (normal)
• Slip indicator flashing: Always flashes during DAC operation (normal)
• Stop lights on: Will illuminate when DAC applies brakes (normal)
• Slight pulsing feel: You may feel brake modulation through pedal or steering (normal)

Real-World Tips from the Community​

Practice DAC Activation in a Controlled Environment First
Test DAC on a moderate gravel descent in a safe location before relying on it in challenging off-road situations. Understanding how the system feels and responds builds confidence.

Source: ToyotaNation forums, 4gtaco.com community discussions

Don't Touch the Pedals During DAC Operation
Community experience confirms manual guidance: Touching brake or gas pedal during DAC operation automatically disengages the system. Let DAC fully manage speed. Your job is steering only.

Source: 4gtaco.com, ToyotaNation discussion threads

Combine DAC with Lower Shift Range for Best Results
Users report selecting S3 or S4 range (automatic) or 2nd/3rd gear (manual) before activating DAC significantly improves effectiveness and reduces brake heat.

Source: Multiple forum discussions (4gtaco.com, tacoma4g.com)

Common Mistake to Avoid​

Confusing DAC with Crawl Control
Multiple forum threads show users trying to activate DAC in 4L (expecting Crawl Control) or expecting Crawl Control features from DAC. These are separate systems activated by the same button depending on transfer case mode.

Correct: DAC = 4H mode, Crawl Control = 4L mode

Source: Community discussions across 4gtaco.com, ToyotaNation

Manual Pages Reference​

Complete DAC Operation Guide:
For the complete official instructions with diagrams, see pages 418-419 of your 2024+ Toyota Tacoma Owner's Manual.

Source Attribution​

Owner's Manual Pages:

• Primary DAC operation and system overview: Pages 418-419
• System components: Page 418
• Activation/deactivation procedures: Pages 418-419
• Indicator states and meanings: Pages 418-419
• Overheat conditions: Page 419
• Operating tips: Page 419

Additional Sources:

• 4gtaco.com (4th Gen Tacoma Forum)
• ToyotaNation
• tacoma4g.com
• MotorTrend (Crawl Control technical article)

Disclaimer:
This guide is derived from the official 2024+ Toyota Tacoma Owner's Manual (OM04041U) with supplementary information from the owner community and reputable automotive sources. Always follow your official owner's manual for warranty compliance. This is a reference guide only.