Toyota Tundra Service Manual: System Description

SYSTEM DESCRIPTION

PRE-COLLISION SYSTEM DESCRIPTION

(a) The pre-collision system uses the pre-collision warning control, pre-collision brake assist control and pre-collision braking control to help avoid a collision or reduce the impact if it determines that the possibility of a collision is high or a collision is unavoidable based on the position and relative speed of a preceding vehicle.

(b) The operation of this system can be turned off and on using the setting screen of the multi-information display.

HINT:

When the pre-collision system is turned off, the PCS warning light in the combination meter assembly will illuminate.

PRE-COLLISION SYSTEM SENSOR DESCRIPTION

(a) The millimeter wave radar sensor assembly and forward recognition camera detect the position and relative speed of preceding vehicles and pedestrians. This information is sent to the millimeter wave radar sensor assembly to determine if the possibility of a collision is high or a collision is unavoidable.

FUNCTION OF MAIN COMPONENTS

OUTLINE OF PRE-COLLISION SYSTEM

(a) Pre-collision Warning:

(1) When the system determines that the possibility of a frontal collision is high, a buzzer will sound and a warning message will be displayed on the multi-information display to urge the driver to take evasive action.

(b) Pre-collision Brake Assist:

(1) When the system determines that the possibility of a frontal collision is high, the system applies greater braking force in relation to how strongly the brake pedal is depressed.

(c) Pre-collision Braking:

(1) When the system determines that the possibility of a frontal collision is high, the system warns the driver. If the system determines that the possibility of a collision is extremely high, the brakes are automatically applied to help avoid the collision or reduce the collision speed.

HINT:

• The vehicle may creep after the pre-collision braking function has operated, the driver should depress the brake pedal as necessary.
• If the accelerator pedal is being depressed strongly or the steering wheel is being turned, the system may determine that the driver is taking evasive action and possibly prevent the pre-collision braking function from operating.

PRE-COLLISION SYSTEM CONTROL OPERATION

PRE-COLLISION SYSTEM OPERATION CONDITIONS

CAUTION:

Always observe the legal speed limit when driving on public roads.

Conditions under which the system may operate even if there is no possibility of a collision

(a) In some situations such as the following, the system may determine that there is a possibility of a frontal collision and operate.

• When passing a vehicle or pedestrian.
• When changing lanes while overtaking a preceding vehicle.
• When overtaking a preceding vehicle that is changing lanes.
• When overtaking a preceding vehicle that is making a left/right turn.
• When passing a vehicle in an oncoming lane that is stopped to make a right/left turn.
• When driving on a road where relative location to vehicle ahead in an adjacent lane may change, such as on a winding road.
• When rapidly closing on a vehicle ahead.
• If the front of the vehicle is raised or lowered, such as when the road surface is uneven or undulating.
• When approaching objects on the roadside, such as guardrails, utility poles, trees or walls.
• When there is a vehicle, pedestrian or object by the roadside at the entrance of a curve.
• When driving on a narrow path surrounded by a structure, such as in a tunnel or on an iron bridge.
• When there is a metal object (manhole cover, steel plate, etc.), steps, or a protrusion on the road surface or roadside.
• When a crossing pedestrian approaches very close to the vehicle.
• When passing through a place with a low structure above the road (low ceiling, traffic sign, etc.).
• When passing under an object (billboard, etc.) at the top of an uphill road.
• When rapidly closing on an electric toll gate barrier, parking area barrier or other barrier that opens and closes.
• When using an automatic car wash.
• When driving through or under objects that may contact the vehicle, such as thick grass, tree branches or a banner.
• When the vehicle is hit by water, snow, dust, etc. from a vehicle ahead.
• When driving through steam or smoke.
• When there are patterns or paint on the road or a wall that may be mistaken for a vehicle or pedestrian.
• When driving near an object that reflects radio waves, such as a large truck or guardrail.
• When driving near a TV tower, broadcasting station, electric power plant, or other location where strong radio waves or electrical noise may be present.

Situations in which the system may not operate properly

(a) In some situations such as the following, a vehicle may not be detected by the millimeter wave radar sensor assembly and forward recognition camera, preventing the system from operating properly:

• If an oncoming vehicle is approaching your vehicle.
• If a vehicle ahead is a motorcycle or bicycle.
• When approaching the side or front of a vehicle.
• If a preceding vehicle has a small rear end, such as an unloaded truck.
• If a preceding vehicle has a low rear end, such as a low bed trailer.
• If a vehicle ahead is carrying a load which protrudes past its rear bumper.
• If a vehicle ahead has extremely high ground clearance.
• If a vehicle ahead is irregularly shaped, such as a tractor or side car.
• If the sun or other light is shining directly on a vehicle ahead.
• If a vehicle cuts in front of your vehicle or emerges from beside a vehicle.
• If a vehicle ahead makes an abrupt maneuver (such as sudden swerving, acceleration or deceleration).
• When suddenly cutting behind a preceding vehicle.
• When a vehicle ahead is not directly in front of your vehicle.
• When driving in inclement weather such as heavy rain, fog, snow or a sandstorm.
• When the vehicle is hit by water, snow, dust, etc. from a vehicle ahead.
• When driving through steam or smoke.
• When driving in a place where the surrounding brightness changes suddenly, such as at the entrance or exit of a tunnel.
• When a very bright light, such as the sun or the headlights of oncoming traffic, shines directly into the forward recognition camera.
• When the surrounding area is dim, such as at dawn or dusk, or while at night or in a tunnel.
• After the engine has started the vehicle has not been driven for a certain amount of time.
• While making a left/right turn and for a few seconds after making a left/right turn.
• While driving on a curve and for a few seconds after driving on a curve.
• If your vehicle is skidding.
• If the front of the vehicle is raised or lowered.
• If the wheels are misaligned.
• If a wiper blade is blocking the forward recognition camera.
• The vehicle is wobbling.
• The vehicle is being driven at extremely high speeds.
• When driving on a hill.
• If the millimeter wave radar sensor assembly is misaligned.

(b) In some situations such as the following, sufficient braking force may not be obtained, preventing the system from performing properly:

• If the braking functions cannot operate to their full extent, such as when the brake parts are extremely cold, extremely hot or wet.
• If the vehicle is not properly maintained (brakes or tires are excessively worn, improper tire inflation pressure, etc.).
• When the vehicle is being driven on a gravel road or other slippery surface.

(c) Some pedestrians such as the following may not be detected by the millimeter wave radar sensor assembly and forward recognition camera, preventing the system from operating properly:

• Pedestrians shorter than approximately 3.2 ft. (1 m) or taller than approximately 6.5 ft. (2 m).
• Pedestrians wearing oversized clothing (a rain coat, long skirt, etc.), making their silhouette obscure.
• Pedestrians who are carrying large baggage, holding an umbrella, etc., hiding part of their body.
• Pedestrians who are bending forward or squatting.
• Pedestrians who are pushing a stroller, wheelchair, bicycle or other vehicle.
• Groups of pedestrians which are close together.
• Pedestrians who are wearing white and look extremely bright.
• Pedestrians in the dark, such as at night or while in a tunnel.
• Pedestrians whose clothing appears to be nearly the same color or brightness as their surroundings.
• Pedestrians near walls, fences, guardrails or large objects.
• Pedestrians who are on a metal object (manhole cover, steel plate, etc.) on the road.
• Pedestrians who are walking fast.
• Pedestrians who are changing speed abruptly.
• Pedestrians running out from behind a vehicle or a large object.
• Pedestrians who are extremely close to the side of the vehicle (outside rear view mirror, etc.).

If the PCS warning light flashes or illuminates and a warning message is displayed on the multi-information display

HINT:

For details on the operation of the PCS warning light and displayed warning messages, refer to Diagnosis System.

Click here

(a) The pre-collision system may be temporarily unavailable or there may be a malfunction in the system.

(b) In the following situations, the warning light will turn off, the message will disappear and the system will become operational when normal operating conditions return:

• When the millimeter wave radar sensor assembly or forward recognition camera or the area around either sensor is hot, such as in the sun.
• When the millimeter wave radar sensor assembly or forward recognition camera or the area around either sensor is cold, such as in an extremely cold environment.
• When a millimeter wave radar sensor assembly is dirty or covered with snow, etc.
• When the part of the windshield glass in front of the forward recognition camera is fogged up or covered with condensation or ice.
• If the forward recognition camera is obstructed, such as when the hood is open or a sticker is attached to the windshield glass near the forward recognition camera.
• When the millimeter wave radar sensor assembly is performing beam axis alignment correction after detecting a misaligned beam axis.

If VSC is disabled

(a) If VSC is disabled, the pre-collision brake assist and pre-collision braking functions are also disabled.

(b) The PCS warning light will turn on and "VSC Turned Off Pre-collision Brake System Unavailable" will be displayed on the multi-information display.

If trailer brake control system malfunction

(a) If trailer brake control system malfunction the pre-collision brake assist and pre-collision braking functions are disabled.

(b) The PCS warning light flashes and "Pre-Collision System Malfunction Visit Your Dealer" or "Pre-Collision System Unavailable" will be displayed on the multi-information display.