Bendix Commercial Vehicle Systems EC-17 ANTILOCK TRACTION CONTROL4/10 - Manual (Page 5)

5
axles (6 x 4) requires 4 speed sensors for antilock only
operation, but have the option to use 6 speed sensors for
enhanced performance of both antilock and traction operation.
- Vehicle power is supplied to the EC-17 ™ controller from
the ignition switch through a 30 amp fuse. The electrical
ground for the EC-17
™ controller is the vehicle chassis.
- A connection for a traction enable switch is provided,
and used when the optional traction feature is installed.
The switch allows traction to be turned on or off manually.
- ATC requires J1922/J1939 drivers requested torque. This
input is necessary to engage differential braking on units
built after mid-year 2000.
OUTPUTS
- Modulators - The Bendix ® M-22 ™ modulator, is the means
by which the EC-17 ™ controller modifies driver applied air
pressure to the service brakes. The modulator is an
electrically controlled air valve located near the service
actuator(s) it controls. It is the last valve that air passes
through on its way to the brake actuator. A wiring harness
connects the modulator to the EC-17
™ antilock controller.
Solenoid valves contained in the modulator provide the
electrical interface between the EC-17
™ controller electronics
and the air brake system. The EC-17 ™ controller is able to
simultaneously and independently control four individual
modulator assemblies. When vehicle power is supplied to
the EC-17
™ controller, a modulator “chuff” test is performed.
When the brake pedal is depressed and the ECU is powered
via the ignition switch, the patented modulator “Chuff” test is
audible. A properly wired modulator will exhaust air with a
sharp (or crisp) audible “Chuff”. On ECU’s manufactured
prior to mid-year 2000, the hold solenoid of a modulator is
energized three times longer than an exhaust solenoid while
the “Chuff” test is being executed. If the modulator hold and
exhaust solenoid wires are reversed the audible “Chuff” is
not crisp because of the extended exhaust energization.
After mid-year 2000, the hold solenoid of the modulator is
energized twice while the exhaust solenoid is energized
once. If the modulator hold and exhaust solenoid wires are
reversed the modulator will exhaust twice during a “Chuff”.
The vehicle modulators will “Chuff” in the sequence: right
front, left front, right rear, left rear. It will execute this exhaust
sequence twice, for a total of eight exhausts. Both patented
audible “Chuff” tests help the mechanic verify when the
modulators are functional and connected correctly without
needing additional test equipment. If an issue is detected
with the modulators, proceed with modulator troubleshooting
or compare the modulator wiring to the vehicle wiring
schematic found in Figure 5.
- An AntiLock dash light through an electrical relay is
connected to, and controlled by, the EC-17
™ controller and
serves as a means of advising the driver of the condition of
the antilock system.
- Two control link connections to the engine or transmission
retarder and its relay are provided on the EC-17
™ controller.
One control link or the other can be utilized, but not both on
the same vehicle. The hardware for one control link conforms
to S.A.E. standard 1708 and the protocol, or coded language
used, conforms to S.A.E. standard J1922. The other control
link conforms to S.A.E. standard J1939. Use of a control
link allows the EC-17
™ controller to temporarily disable the
retarder during certain modes of operation. Units built after
mid-year 2000 have improved retarder operation, allowing
the retarder to re-enable sooner following an ABS event.
While the EC-17
™ controller is capable of this function, and
connections are provided, it is not always used. Use of the
retarder disable function is not essential but highly
recommended for vehicles equipped with a retarder.
Note: The EC-17 ™ controller can also disable the retarder
using the same S.A.E. J1922 or S.A.E. J1939
protocol it uses to control the traction control, engine
torque limiting feature. For this redundant retarder
disable to function, the EC-17
™ controller must be
connected to the engine control module (as would
be the case if the EC-17
™ controller is programmed
for the traction control, torque limiting feature).
- The diagnostic link enables the EC-17 ™ controller to
"report" its operating condition to an external computer using
the Bendix diagnostic communications interface hardware
in response to certain commands it receives from software
like Bendix ACom
® for Windows*. The EC-17 ™ controller
diagnostic link hardware conforms to S.A.E. standard J1708.
The protocol, or coded language used, conforms to S.A.E.
standard J1587. While connections are provided for this
function, it is not always used. The use of the diagnostic
link is essential for the servicing and reconfiguration of the
EC-17N
™ controller. The diagnostic link is also used by
the EC-17 ™ controller to request additional information
and to assist diagnostics and troubleshooting.
FIGURE 6 - M-30 ™ , M-32 ™ , AND M-32QR ™ MODULATORS
* Windows is a registered trademark of Microsoft Corporation.
M-32QR ™
MODULATOR
M-32 ™
MODULATOR
ELECTRICAL
CONNECTOR
DELIVERY
(PORT 2)
SUPPLY
(PORT 1)
EXHAUST
(PORT 3)
M-30 ™
MODULATOR