Bendix Commercial Vehicle Systems EC-80 ABS ATC SD - Manual (Page 9)

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3. During an ATC event (the lamp will flash rapidly at a
rate of 2.5/second). When ATC is no longer active, the
ATC active/indicator lamp turns off.
4. When the ECU is placed in the ATC off‑road mode (the
lamp will flash steadily every 2.5 seconds). This notifies
the vehicle operator that the off‑road mode is active.
Differential Braking
Differential braking is automatically activated when drive
wheel(s) on one side of the vehicle are spinning. This
typically occurs on asphalt road surfaces with patches of
ice. The traction system will then lightly apply the brake to
the drive wheel(s) that are spinning. The vehicle differential
will then drive the wheels on the other side of the vehicle.
Differential braking is available at vehicle speeds up to
25 MPH.
Disabling ATC Differential Braking
ATC differential braking is disabled under the following
conditions:
1. During power‑up (e.g. when the vehicle is started), until
the ECU detects a service brake application.
2. If the ECU receives a J1939 message indicating that
the vehicle is parked.
3. When the Dynamometer Test Mode is active. The
Dynamometer Test Mode is entered using the
diagnostic blink code switch or by using a diagnostic
tool (such as Bendix ® ACom ® Diagnostics).
4. In response to a serial communications request from
a diagnostic tool.
5. During brake torque limiting to avoid overheating of the
brakes.
6. When certain Diagnostic Trouble Code conditions are
detected.
Engine Torque Limiting (ETL) with Smart ATC ™
Traction Control
The Bendix ® EC‑80 ™ controller uses Engine Torque Limiting
to control drive axle wheel slip. This is communicated to
the engine control module (using J1939), and is available
at all vehicle speeds.
Bendix ® Smart ATC ™ Traction Control
The Bendix EC‑80 ATC controller has an additional feature
known as Smart ATC ™ traction control. Smart ATC ™
traction control monitors the accelerator pedal position
(using J1939) to help provide optimum traction and vehicle
stability. By knowing the driver’s intention and adapting
the target slip of the drive wheels to the driving situation,
the Smart ATC ™ traction control allows higher wheel slip
when the accelerator pedal is applied above a preset level.
The target wheel slip is decreased when driving through a
curve for improved stability.
Disabling ATC Engine Control and Smart ATC ™ Traction
Control
ATC Engine Control and Smart ATC
™ traction control will
be disabled under the following conditions:
1. In response to a serial communications request from
an off‑board tool.
2. At power‑up until the ECU detects a service brake
application.
3. If the ECU receives a J1939 message indicating that
the vehicle is parked.
4. If the Dynamometer Test Mode is active. This may be
accomplished via an off‑board tool or the diagnostic
blink code switch.
5. When certain Diagnostic Trouble Code conditions are
detected.
Optional ATC Off-Road Mode
In some road conditions, the vehicle operator may desire
additional drive wheel slip when ATC is active. The Bendix
EC‑80 ATC controller has an optional control mode to
permit this desired performance.
The vehicle operator can activate the off‑road function with
a switch on the dash panel. Alternately, a J1939 message
may be used to place the vehicle in this mode. The ATC
indicator lamp will flash continually to confirm that the off-
road ATC function is engaged.
To exit the ATC off‑road mode, depress and release the
ATC off‑road switch.
Drag Torque Control Functional Overview
Bendix EC‑80 ATC controllers have a feature referred to as
drag torque control which reduces wheel slip on a driven
axle due to driveline inertia. This condition is addressed
by increasing the engine torque to overcome the inertia.
Drag torque control increases vehicle stability on low‑
traction road surfaces during down‑shifting or retarder
braking.
DYNAMOMETER TEST MODE
ATC must be disabled prior to conducting any
dynamometer testing. When the Dynamometer Test
Mode is enabled, ATC brake control and engine control,
along with drag torque control, are turned off. This
test mode is used to avoid torque reduction — or
torque increase and brake control activation — when
the vehicle is operated on a dynamometer for testing
purpose.
The Dynamometer Test Mode may be activated by pressing
and releasing the diagnostic blink code switch five (5) times
or by using a hand‑held or PC‑based diagnostic tool.