8
AUTO CALIBRATION
For optional ATC performance the ECU utilizes a feature
referred to as auto calibration. Auto calibration allows the
ECU to compensate for various tire sizes throughout the life
of the vehicle. As there are many conditions that can result
in the appearance of a change in the tire size, several items
must be satisfied before the auto calibration feature is active.
The auto calibration feature would automatically change the
ECUs imbedded tire sizes if the difference exceeded
approximately 8%. If issues occur with your ATC due to tire
size changes please contact 1-800-AIR-BRAKE or
1-800-247-2725 for assistance.
SINGLE FAILURE
The following list and chart describes how the antilock and
traction systems respond to a specific component failure.
(Note: right and left; front, mid and rear are determined from
the driver's seat. Left front is therefore the corner closest to
the driver.)
For example, if the right mid sensor ("RM Sensor" on the
chart) fails, front and rear antilock will still be operative.
Traction will be disabled. On those axles where antilock is
disabled the system reverts to standard air braking.
Front modulator - If a front modulator fails, antilock on that
wheel is disabled. Antilock and traction on all other wheels
remains active.
Rear modulator - A rear modulator failure disables the traction
system. Antilock on that wheel will also be disabled, but
antilock on all other wheels remains active.
Front sensor - The wheel is still modulated using input from
the opposite sensor on the front axle. The traction system
is disabled.
Mid or rear sensor - In a four sensor system, antilock on
that wheel(s) is disabled, but antilock on all other wheels
remains active. In a six sensor system, antilock remains
active using input from the remaining functional sensor. In
both the four and six sensor system traction control is
disabled.
Controller - Antilock and traction are disabled. The system
reverts to standard air braking.
Traction solenoid - Traction control is disabled. Antilock
remains active.
Engine Control Module - If the engine control module (ECM)
or the wiring from the EC-17
™
controller to the ECM fails,
traction control is disabled. Antilock remains active.
Voltage - If system voltage is out of range, antilock and
traction are disabled. The system reverts to standard air
braking.
MULTIPLE FAILURES
In the event that multiple failures occur, the dash lamp will
react as it normally would during a single failure, and the
EC-17
™
controller equipped with LEDs will show one
diagnostic trouble code at a time. When the first diagnostic
trouble code is fixed and the system is reset, the next
diagnostic trouble code area will appear at the LEDs. This
way, the driver or mechanic does not lose track of diagnostic
trouble code areas, and the system is not restored until
each and every error is corrected and the EC-17
™
controller
is cleared of all diagnostic trouble codes.
DIAGNOSTIC TROUBLE CODE LOCATION
SYSTEM STILL OPERATING (YES/NO)
Failed
ABS Front
ABS Rear
Traction
Std.
Device
Left Right
Left Right
Braking
RF Sensor
YES
YES
YES YES
NO
YES
LF Sensor
YES
YES
YES YES
NO
YES
RM Sensor
YES
YES
YES YES
NO
YES
LM Sensor
YES
YES
YES YES
NO
YES
RR Sensor
YES
YES
YES NO
1
NO
YES
LR Sensor
YES
YES
NO
1
YES
NO
YES
RF Modulator YES
NO
YES YES
YES
YES
LF Modulator
NO
YES
YES YES
YES
YES
RR Modulator YES
YES
YES
NO
NO
YES
LR Modulator YES
YES
NO
YES
NO
YES
Controller
NO
NO
NO
NO
NO
YES
Tract. SolenoidYES
YES
YES YES
N0
YES
Engine Control
Module
2
YES
YES
YES YES
NO
YES
Voltage
2
NO
NO
NO
NO
NO
YES
1
ABS is still available in 6 sensors system if mid sensor is functional
2
When ECM wiring or voltage "corrects" itself, system is restored.
FRONT OF VEHICLE
REAR OF VEHICLE
DRIVER
RIGHT FRONT
LEFT FRONT
RIGHT REAR
LEFT REAR
RIGHT MID
LEFT MID
RESET
SWITCH
FIGURE 7 - EC-17
™
CONTROLLER LED DIAGNOSTIC
DISPLAY
FRT
MID
RER
RHT
LFT
TRC
MOD
SEN
ECU
VLT
FRONT
MIDDLE
REAR
RIGHT
LEFT
TRACTION
MODULATOR
SENSOR
ECU
VOLTAGE
