Automatic Traction Control
Vehicles with electronic engines and ABS may have Automatic Traction Control (ATC). On these vehicles, the ATC system automatically limits wheel spin during reduced-traction situations. In normal braking applications, the standard air brake system is in effect.
An additional solenoid valve is installed. During reduced-traction situations, the ATC solenoid valve controls air pressure to the modulator valves and they in turn increase, hold, or reduce pressure to the appropriate brake chambers to provide better traction whenever wheel spin occurs.
When the ATC system is in the NORMAL mode, it will apply gentle braking to the spinning wheel, to feed power to the wheel(s) with better traction. If both wheels are spinning, the system will signal the engine to reduce power.
If the system detects wheel spin or a stability event, the wheel spin/stability telltale illuminates and an alert is shown on the driver display. See Table..
Table 1, Brake System Warnings, Indicators, and Messages
|
Brake System Warnings, Indicators, and Messages |
||||
|---|---|---|---|---|
|
Telltale |
Color |
Description |
Driver Display |
|
 |
Red |
Low Air Pressure (EPA10 and Newer) |
Indicates air pressure in the primary or secondary reservoir has dropped below approximately 70 psi (483 kPa). A buzzer will also sound if the park brake is released or if the vehicle is moving--depending on vehicle options. |
 |
 |
Red |
Parking Brake (EPA10 and Newer) |
Indicates the parking brake is engaged. |
N/A |
 |
Amber |
Vehicle ABS |
Momentary illumination indicates the vehicle ABS is engaged. Solid illumination indicates a problem with the vehicle ABS. Repair the ABS immediately to ensure full braking capability. |
N/A |
 |
Amber |
Trailer ABS |
Momentary illumination indicates the trailer ABS is engaged. Solid illumination indicates a problem with the trailer ABS. Repair the ABS immediately to ensure full braking capability. |
N/A |
 |
Amber |
Stability Event |
Flashing indicates a stability event has been detected, and the ESC system is active. Solid illumination indicates a problem with the stability system. Repair the ESC system immediately to ensure full stability capability. For more information on the ESC system, see General Description, Standard Adaptive Cruise Control. |
N/A |
 |
Amber |
Wheel Spin Event |
Flashing indicates a wheel spin event has been detected, and the ATC system is active. |
N/A |
 |
ATC Deactivated |
Indicates the ATC SPIN button has been pressed to allow wheel slip. |
 |
|
 |
Green |
Engine Brake |
Indicates the engine brake is enabled. |
N/A |
Table 1, Brake System Warnings, Indicators, and Messages
Pressing the ATC SPIN switch ( see Fig.) shuts ATC off and allows drive wheel spin. An alert is shown on the driver display. Pressing the switch again, or cycling the ignition key, will cycle the system back to normal operation.
Fig. 1, ATC SPIN Switch
Notice: The ATC spin feature is intended to be used under specific slippery conditions that require momentary increased wheel spin. Using this option for an extended period of time may damage the vehicle brake system.
After the ignition switch is turned on, the TRACTOR ABS lamp comes on for about three seconds. After three seconds, the warning light goes out if all of the tractor's ABS components are working.
Important: If the ABS warning light does not work as described above, or comes on while driving, repair the ABS immediately to ensure full antilock braking capability.