PREVOST X3-45 Multiplex, Maintenance Manual

Page: 589 / 1422

15
REVISED 5/31/05
Diagnostics:
The yaw rate sensor is only operational in conjunction with
an Advanced ABS ECU. No independent diagnostics can
be performed on the sensor.
Removal:
1. Unplug sensor cable assembly from body of sensor.
The connector must be twisted and pulled gently to
release.
2. In some mounting configurations, the sensor can be
removed independently from its mounting bracket.
Otherwise, remove entire assembly, then remove
sensor from bracket.
3. Take note of the direction in which the connector is
pointed.
Installation:
1. Obtain a new sensor. The sensor is not repairable in the
field. WARNING: Only Bendix-approved replacement
sensors must be used to prevent negatively affecting
antilock system reliability and braking performance
issues.
2. Assembly yaw rate sensor housing to mounting bracket.
The bracket must be the same design as used on the
original vehicle configuration.
3. Using three M8 size bolts, the fixing torque should be
between 18 and 22N. The connector should be facing
in the same direction as the removed sensor. The unit
must not be installed upside-down where there is a
pressure-balancing hole.
4. The sensor should be as level as possible and parallel
to the road surface when installed on the vehicle.
5. Reconnect the connector. Ensure that there will be no
force applied to the sensor because the connector is
pulling on the sensor body.
CAUTION: When removing or installing the sensor,
care must be used to prevent damage. Do not strike
or pry the sensor. Do not use an impact tool to install
the mounting hardware.
Sensor Location Modifications
The location and orientation of the Yaw Rate Sensor must
not be altered. When servicing, an identical component
must be used in the same orientation (using OEM brackets
& torque requirements). During installation follow the OEM
leveling guidelines.
Yaw Rate Sensor Calibration:
The yaw rate sensor calibration can only be achieved via
the Advanced ABS ECU. The sensor must be recalibrated
after any of these situations:
• Replacement of the sensor
• After an accident that may have led to damage of the
yaw rate sensor
The calibration procedure is preformed using Bendix
®
ACom
™
Diagnostics V4.0 or higher.
See “Troubleshooting Diagnostic Trouble Codes: Yaw Rate
Sensor” for the calibration procedure.
BRAKE DEMAND SENSOR CALIBRATION
Calibration must be performed under the following conditions:
• After servicing any pressure sensor related DTCs
• Replacement of any sensor
The calibration procedure is performed using Bendix
®
ACom
™
Diagnostics V4.0 or newer versions.
See “Troubleshooting Diagnostic Trouble Codes:
Brake Demand Sensor/Load Sensor” for the calibration
procedure.
PRESSURE SENSOR INSTALLATION
REQUIREMENTS
Service Checks:
1. Check all wiring and connectors. Make sure all
connections are free from visible damage.
2. Examine the sensor. Make sure the sensor and its
interface to the pressure location are not damaged.
Diagnostics:
The pressure sensor can be independently diagnosed
when supplied with a five volt voltage supply to the B
location and ground to the A location. Signal output on
the C location should read approximately 0.5V if there is
no pressure applied. The signal output should increase
proportionately as pressure is applied, up to a maximum
of 4.5V at 150 psi.
Removal:
1. Unplug sensor cable assembly from body of sensor.
Pull gently on the mounting tab and connector until it
disengages.
2. Remove sensor from its pressure mounting using
approved air brake push in fitting tools.
Installation:
1. Obtain a new sensor. The sensor is not repairable in
the field.
2. Insert sensor into pressure fitting using approved
tools.
3. Reconnect the connector. Ensure that there will be no
force applied to the sensor because the connector is
pulling on the sensor body.
4. If the wire harness leading to the sensor is being
replaced, ensure that it is adequately tie wrapped.
Pressure Sensor Calibration:
There is no need for pressure sensor calibration as long
as the part replaced its identical to the part removed and
a component approved for use with the Bendix Advanced
ABS system. However, replacement of brake demand
sensors or clearing of demand pressure sensor related
DTCs require the following:
1. Use of ACom V4 or newer to clear the active p-sensor
fault.
2. Carrying out the demand p-sensor initialization
procedure which involves applying service brakes of
90 psi or greater for 3 sec (while stationary).
Once this procedure is carried out successfully, if there are
no other active DTCs, ATC/ESP indicator will no longer
illuminate.