PREVOST X3-45 Multiplex, Maintenance Manual

Page: 33 / 1422

SECTION 01: ENGINE
PA1562
3
1. VOLVO D13 ENGINE
1.1 SYSTEM OVERVIEW
NOTE
The “Premium Tech Tool” (PTT) is the
preferred tool for performing diagnostic work.
Contact your local dealer for more information.
The Engine Management System (EMS)
controls many engine functions such as: fuel
timing and delivery, engine protection functions,
engine brake operation, EGR valve function and
the turbocharger nozzle function. The Engine
Electronic Control Unit (EECU) along with other
supporting control units and sensors are
responsible for monitoring and controlling these
functions. These control units communicate
through the J1939 high speed serial data line to
share data.
In addition to their control functions, the modules
have on-board diagnostic capabilities. The on-
board diagnostics are designed to detect faults
or abnormal conditions that are not within their
operating parameters. When the system detects
a fault or abnormal condition, the fault will be
logged in one or both of the modules’ memory.
The vehicle operator will be advised that a fault
has occurred by the illumination of a malfunction
indicator lamp and a message in the driver
information display, if equipped. The module
may initiate the engine shutdown procedure if
the system determines that the abnormal
condition could damage the engine. In some
situations, the system will enter the "limp home"
mode. Limp home mode allows continued
vehicle operation but, the system may substitute
a sensor or signal value that may result in
reduced engine performance.
Fault codes logged in the system memory, can
later be read to aid in diagnosing the fault.
These faults can be read via a diagnostic
computer or through the instrument cluster
display, if equipped. The “Premium Tech Tool”
(PTT) is the preferred tool for performing
diagnostic work. Using a diagnostic computer
(or PTT) connected to the Serial
Communication Port, expands the technicians
diagnostic capabilities with additional data and
tests.
For diagnostic software, contact your local
dealer.
The following is a list of engine sensors that
provide input to the EMS:
•
Ambient Air Temperature Sensor
•
Ambient Pressure sensor
•
Boost Air Pressure (BAP) Sensor
•
Camshaft Position (Engine Position) Sensor
•
Crankshaft Position (Engine Speed) Sensor
•
Differential Pressure DPF Sensor
•
EGR Differential Pressure Sensor
•
EGR Temperature Sensor
•
Engine Coolant Level (ECL) Sensor
•
Engine Coolant Temperature (ECT) Sensor
•
Engine Oil Pressure (EOP) Sensor
•
Engine Oil Level (EOL) Sensor
•
Engine Oil Temperature (EOT) Sensor
•
Exhaust Temperature Sensor (DPF
Sensors)
•
Fuel Pressure Sensor
•
Intake Air Temperature And Humidity (IATH)
Sensor
•
Intake Manifold (Boost) Temperature Sensor
•
Throttle Position (TP) Sensor
•
Turbo Speed Sensor
•
Variable Geometry Turbocharger (VGT)
Position Sensor
Sensors
Ambient Air Temperature Sensor
The Ambient Air Temperature Sensor is used to
detect the outside air temperature. The sensor
modifies a voltage signal from the ECM. The
modified signal returns to the ECM as the
ambient air temperature. The sensor uses a
thermistor that is sensitive to the change in
temperature. The electrical resistance of the
thermistor decreases as temperature increases.
The Ambient Air Temperature Sensor is located
in the front of the vehicle.
Ambient (Atmospheric) Pressure Sensor
The Ambient (Atmospheric) Pressure Sensor
contains a pressure sensitive diaphragm and an
electrical amplifier. Mechanical pressure applied
to the diaphragm causes the diaphragm to
deflect and the amplifier to produce an electrical
signal proportional to the deflection.