Bendix Commercial Vehicle Systems EC-80 ABS ATC SD - Manual (Page 6)

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The ABS Lamp Illuminates:
1. During power‑up (e.g. when the vehicle is started) and
turns off after the self‑test is completed, providing no
Diagnostic Trouble Codes (DTCs) are present on the
tractor.
2. If the ECU is unplugged or has no power.
3. When the ECU is placed into the ABS off‑road mode
(the lamp flashes rapidly).
4. To display blink codes for diagnostic purposes after the
external diagnostic switch is activated.
Certain Bendix ® EC‑80 ™ controllers communicate with
other vehicle control modules to operate the ABS indicator
lamp using. To confirm if a specific ECU uses serial
communications, see the Controller Specifications box
on page 4.
Indicator Lamp Control Using Serial
Communications Links
As mentioned above, depending on the vehicle
manufacturer, the dash indicator lamps (ABS, ATC and
trailer ABS) may be controlled using serial communications
link. In these cases, the Bendix EC‑80 controller will send
a serial communications message over the J1939 links
indicating the required status of the lamp(s). Another
vehicle control module receives the message and controls
the indicator lamp(s).
Retarder Relay Disable Output
The retarder relay disable output may be used to control
a retarder disable relay.
When configured to use this output, the ECU will energize
the retarder disable relay and inhibit the use of the retarder
as needed.
SAE J1939 Serial Communications
A Controller Area Network (CAN) data link (SAE J1939) is
provided for communication. This link is used for various
functions, such as:
• To disable retarding devices during ABS operation
• To request that the torque converter disable lock‑up
during ABS operation
• To share information such as wheel speed and ECU
status with other vehicle control modules
Bendix EC‑80 ATC controllers utilize the J1939 data link
for ATC and drag torque control functions.
Trailer ABS Indicator Lamp Control
Certain models of the Bendix EC‑80 controller activate a
trailer ABS indicator lamp (located on the dash panel) that
indicates the status of the trailer ABS unit on one, or more
trailers or dollies. Typically, the Bendix EC‑80 controller
directly controls the trailer ABS indicator lamp based on
the information it receives from the trailer ABS.
Alternatively, some vehicles require the Bendix EC‑80
controller to activate the trailer ABS indicator lamp by
communicating with other vehicle controllers using serial
communications. To confirm if a specific ECU uses serial
communications, see the Controller Specifications box on
page 4.
ATC Lamp Output/ATC Off-Road Switch Input
The ATC dash lamp is controlled by the Bendix EC‑80 ATC
ECU. The ATC lamp illuminates:
1. During power‑up (e.g. when the vehicle is started for
approximately 2.5 seconds) and turns off after the
self‑test is completed, providing no Diagnostic Trouble
Codes are present.
2. When ATC is disabled for any reason.
3. During an ATC event (the lamp will flash rapidly at a
rate of 2.5/second).
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.
Interaxle Differential Lock Control (AWD Transfer Case)
A Bendix
EC‑80 ATC ECU can control the interaxle
differential lock (AWD transfer case). This is recommended
on AWD vehicles, but the ECU must be specially configured
to provide this feature. For help with configuring an ECU,
use the information in the Controller Specifications box on
page 4 to contact Bendix.
POWER-UP SEQUENCE
The vehicle operator should verify proper operation
of all installed indicator lamps (ABS, ATC, and trailer
ABS) when applying ignition power and during vehicle
operation. See Chart 2 on page 5.
Lamps that do not illuminate as expected when ignition
power is applied, or remain illuminated, indicate the need
for maintenance.
ABS Indicator Lamp Operation
The ECU will illuminate the ABS indicator lamp for
approximately three seconds when ignition power is
applied, after which the lamp will extinguish if no Diagnostic
Trouble Codes are detected.
The ECU will illuminate the ABS indicator lamp whenever
full ABS operation is not available due to a Diagnostic
Trouble Code. In most cases, partial ABS is still available.
ATC Status/Indicator Lamp Operation
The ECU will illuminate the ATC lamp for approximately
2.5 seconds when ignition power is applied, after which
the lamp will extinguish, if no Diagnostic Trouble Codes
are detected.