(3) Refill coolant system to proper level with
proper mixture of coolant (Refer to 7 - COOLING/
ENGINE/COOLANT - STANDARD PROCEDURE).
(4) Install engine cover (Refer to 9 - ENGINE -
INSTALLATION).
(5) Connect negative battery cable.
WARNING: Use extreme caution when engine is
operating. Do not stand in a direct line with fan. do
not put your hands near pulleys, belts or fan. Do
not wear loose clothes.
(6) Start engine and inspect for leaks.
ENGINE COOLANT THERMO-
STAT
REMOVAL
WARNING: RISK OF INJURY TO SKIN AND EYES
FROM SCALDING WITH HOT COOLANT. RISK OF
POISONING FROM SWALLOWING COOLANT. DO
NOT OPEN COOLING SYSTEM UNLESS COOLANT
TEMPERATURE IS BELOW 90ÉC (194ÉF). OPEN CAP
SLOWLY TO RELEASE PRESSURE. STORE COOL-
ANT IN SUITABLE AND APPROPRIATELY MARKED
CONTAINER. WEAR PROTECTIVE GLOVES,
CLOTHES AND EYE WEAR.
NOTE: Inspect condition of all clamps and hoses,
replace as necessary.
(1) Disconnect negative battery cable.
(2) Partially drain engine coolant (Refer to 7 -
COOLING/ENGINE/COOLANT - STANDARD PRO-
CEDURE).
(3) Unplug connector, pull off locking element and
pull out coolant temperature sensor.
(4) Detach air intake hose at charge air distribu-
tion pipe.
(5) Detach coolant hoses at thermostat housing.
(6) Unscrew cap at oil filter housing.
(7) Remove thermostat housing (Fig. 8).(8) Clean all sealing surfaces.
INSTALLATION
(1) Clean all sealing surfaces.
(2) Position and install thermostat housing with
new gasket (Fig. 8). Tighten bolts to 9N´m (80
lbs.in.).
NOTE: Inspect condition of all clamps and hoses,
replace as necessary.
(3) Install cap at oil filter housing.
(4) Connect coolant hoses and vent hose (Fig. 8).
(5) Attach air intake hose at charge air distribu-
tion pipe.
(6) Close coolant drain.
(7) Connect negative battery cable.
(8) Fill coolant system to proper level with appro-
priate coolant mixture (Refer to 7 - COOLING/EN-
GINE/COOLANT - STANDARD PROCEDURE).
WARNING: USE EXTREME CAUTION WHEN ENGINE
IS OPERATING. DO NOT STAND IN DIRECT LINE
WITH FAN. DO NOT PUT YOUR HANDS NEAR PUL-
LEYS, BELTS OR FAN. DO NOT WEAR LOOSE
CLOTHES.
(9) Start engine and inspect for leaks.
Fig. 8 THERMOSTAT HOUSING ASSEMBLY
1 - O-RING
2 - CLAMP
3 - COOLANT TEMPERATURE SENSOR
4 - FUEL LINE W/BRACKET
5 - THERMOSTAT HOUSING ASSEMBLY
6 - COOLANT HOSE
7 - CLAMP
8 - COOLANT HOSE
9 - GASKET
7 - 16 ENGINEVA
NOTE: Inspect condition of all clamps and hoses,
replace as necessary.
(1) Disconnect the negative battery cable.
(2) Drain cooling system (Refer to 7 - COOLING/
ENGINE/COOLANT - STANDARD PROCEDURE).
(3) Remove viscous fan clutch.
(4) Detach fuel lines from the brackets at the
water pump.
(5) Detach the coolant hoses at the water pump
(Fig. 13).
VAENGINE 7 - 21
(6) Press off cap at belt guide pulleys.
(7) Remove belt guide pulleys.
(8) Remove water pump retaining bolts and
remove water pump.
INSTALLATION
NOTE: Clean all mating surfaces.
(1) Fit existing accessory drive belt pulley onto the
water pump.
(2) Properly position water pump with new gasket
to the engine and tighten bolts to 14 N´m (124 lbs.
in)., M8 (20 N´m (177 lbs. in.) (Fig. 13).
NOTE: Be sure to install the washer behind the
guide pulley to assure proper alignment.
(3) Install belt guide pulleys. Tighten bolts to 35
N´m (26 lbs. ft.) (Fig. 13).
(4) Attach the coolant hoses to the water pump
and tighten clamps (Fig. 13).
(5) Attach fuel lines to the brackets at the water
pump.(6) Install accessory drive belt.
(7) Install viscous fan clutch.
(8) Close radiator and or engine drain plug.
(9) Refill cooling system to proper level (Refer to 7
- COOLING/ENGINE/COOLANT - STANDARD PRO-
CEDURE). Check for leaks.
Fig. 13 WATER PUMP
1 - GASKET 5 - CAP
2 - WASHER 6 - WATER PUMP
3 - GUIDE PULLEY 7 - COOLANT HOSE
4 - BOLT 8 - COOLANT HOSE
7 - 22 ENGINEVA
INSTALLATION
(1) Position the central timer module in the vehicle
(2) Connect the wire harness connectors to the
central timer module.
(3) Install the screws that secure the central timer
module. Tighten the screws securely.
(4) Route the seat belt latch wire lead through the
hole in the closeout panel and position the panel
beneath the driver seat cushion
(5) Install the screws that secure the closeout
panel beneath the driver seat cushion. Tighten the
screws securely.
(6) Connect the wire harness connector to the seat
belt latch connector.
(7) Slide the driver seat to back to its original posi-
tion.
(8) Reconnect the negative battery cable.
CONTROLLER ANTILOCK
BRAKE
DESCRIPTION
The Controler Antilock Brake (CAB) is mounted to
the Hydraulic Control Unit (HCU) and operates the
ABS system.
REMOVAL
(1) Remove the negative battery cable from the
battery.
(2) Pull up on the CAB harness connector release
and remove connector.
(3) Remove the CAB mounting bolts.
(4) Remove the CAB from the HCU.
INSTALLATION
(1) Install CAB to the HCU.
(2) Install mounting bolts. Tighten to 2 N´m (16 in.
lbs.).
(3) Install the wiring harness connector to the
CAB and push down on the release to secure the con-
nector.
(4) Install negative battery cable to the battery.
ENGINE CONTROL MODULE
DESCRIPTION
The electronic control module (ECM) is mounted to
the left lower dash panel and consists of an electronic
printed circuit board which is designed as a milliliter
board assembly fitted on both sides. The routing of
the wiring harness connector at the ECM connector
are split into interfering cables and sensitive cables
in order to achieve improved electromagnetic compat-
ibility. The smaller wiring harness connector is used
for the vehicle wiring harness and the larger harness
is used for the engine wiring harness. The ECM
stores engine specific data, monitors the connected
sensor and analyzes their measurement (Fig. 2).
Its task consists in controlling the following sys-
tems in line with the analysis of the input signals:
²Fuel Supply System
²Injected Quantity Control
²Emission Control System
²Charge Pressure Control
²Cruise Control
²A/C Compressor Shut-Off
²Pre-Heating Output Relay for the Glow Plugs
²Vehicle Theft
²Air Bag
²Monitors inputs/outputs, checks plausibility and
stores faults
²Share information with other control modules
²Diagnosis
If a sensor should fail, provided the fault is not
serious, the ECM will continue to operate the engine
in Limp-Home Mode (emergency mode) using a
default value for the missing signal. The ECM
ensures that, continuing to operate the engine will
not cause damage or effect safety, otherwise a Engine
shut-off process will be carried out (Fig. 3).Fig. 1 Central Timer Module
1 - DRIVER SEAT
2 - WIRE HARNESS CONNECTOR
3 - SCREW (2)
4 - CLOSEOUT PANEL
5 - CENTRAL TIMER MODULE
6 - WIRE HARNESS CONNECTOR (2)
7 - SCREW (2)
VAELECTRONIC CONTROL MODULES 8E - 3
ECM Control Strategy The engine control module
is involved with a variety of functions such as: (Fig.
3)
²Individual injector activation
²Engine idle speed control to ensure smooth
engine idling independent of engine load
²Ride comfort function such as anti jerk control:
The CDI control module detects irregularities in
engine speed (resulting, for example, from load
changes or gear shift) from the signal supplied by the
crankshaft position sensor and reduces them by
adjusting the quantity injected into each of the cylin-
ders
²Constant RPM (high idle feature) for ambulance
vehicle bodies equipped with electrical appliances
²Starter control, immobilizer, cruise control, kick
down, air conditioner
²Maintenance computer ASSYST (optional)
²Glow plug for pre-heating, post heating and
intermittent heating
²Error code memory/diagnostics, communication
interface for diagnosis and handling the fault codes
²The maximum vehicle speed is programmable
from 19±82 m.p.h. The standard is 82 m.p.h.
Fig. 2 ECM
1 - MASS AIR FLOW SENSOR 8 - CHARGE AIR PRESSURE SENSOR
2 - TURBOCHARGER SERVO MOTOR 9 - CHARGE AIR TEMPERATURE SENSOR
3 - CAMSHAFT POSITION SENSOR 10 - COOLANT TEMPERATURE SENSOR
4 - ENGINE OIL SENSOR 11 - FUEL RAIL PRESSURE SENSOR
5 - CRANKSHAFT POSITION SENSOR 12 - FUEL TEMPERATURE SENSOR
6 - PRESSURE REGULATOR VALVE 13 - FUEL QUANTITY CONTROL VALVE
7 - EGR VALVE 14 - AIR INTAKE PRESSURE SENSOR
8E - 4 ELECTRONIC CONTROL MODULESVA
New software has been loaded to the ECM for EGR
control. This is due to the wider operating range and
larger volume of recirculated gas. There is a consid-
erable number of new, adapted, and optimized func-
tions, particularly with regard to injection, EGR,
boost control, sensing of the input parameters and
the signaling of the actuators (Fig. 3).
²The rail pressure control achieved by signaling
the quantity control valve in the high pressure pump
and the pressure regulator results in reduced power
consumption of high pressure pump and in lowering
fuel pressures
²Individual cylinder torque control for smooth
engine running: using the crankshaft position sensor
signals, the ECM detect non-uniform engine running
results from uneven torque contributions of the indi-
vidual cylinders and adjust the injection quantities of
the individual injectors so that all cylinders make the
same torque contribution
²A relay is used for activating the electric in-tank
fuel pump
²Heated crankcase ventilation to ensure pressure
compensation even at low temperatures
²Improved boost pressure control using an elec-
tric variable nozzle turbine actuator with position
feed back
²Controlled fuel heating using the high pressure
pump closed-loop control
²Translation of the drive input received from the
accelerator pedal module which is equipped with
dual hall sensors²Measurement of the intake air mass using new
mass air flow (MAF) sensor with increase precision
and extended measuring range
²O2 sensor for measuring the amount of oxygen
in the exhaust in order to calculate the air to fuel
ratio. With the intake air mass being known, the
injected fuel quantity can be calculated from the air
to fuel ratio
²Activation of the O2 sensor heater to burn off
deposits
²Full load EGR with a more precise, model based
EGR closed-loop control. The ECM calculates the
EGR rate from the various sensor signals. Using the
calculate EGR rate in percent instead of the fresh air
mass flow as a control parameter enables a more pre-
cise control of the EGR rate as well as better correc-
tion of the target value.
The oxygen sensor signal can be used in combina-
tion with the mass air flow signal, the injection
quantity signal and pressure and temperature sig-
nals to perform the following functions for optimized
closed loop control and monitoring of emissions
related components:
²Injection valve quantity drift compensation in
partial load range: the oxygen content in the exhaust
is calculated from the air mass and from injection
quantity signal and is compared to the air-fuel ratio
as measured by the sensor. If the calculated air-fuel
ratio differs from the measured air-fuel ratio, the is
no correction of the injection quantity but the EGR
Fig. 3 ECM CONTROL
VAELECTRONIC CONTROL MODULES 8E - 5
rate and boost pressure are adjusted to the actual
injection quantity.
²Injection valve quantity drift compensation in
full load range: this function is to limit the maximum
injection quantity for engine protection. The injection
quantity signal is compared to the injection quantity
calculated from the oxygen sensor signal and MAF
signal. If the comparison shows that the actual injec-
tion quantity is too high, it is limited to the maxi-
mum permissible injection quantity
²Air-fuel ratio controlled smoke limiter (full load):
the smoke limiter limits the injection quantity on the
basis of the air-fuel ratio permissible at the smoke
limit depending on the measure mass air flow and
the calculated EGR rate. As a consequence, the gen-
eration of smoke due to an excess injection quantity
is avoided under all operating conditions. At the
same time, the oxygen sensor signal is used to
ensure that the air-fuel ratio is adjusted accordingly
A function referred to as air flow sensor drift com-
pensation detects and corrects the possible drifting of
the MAF sensor by comparing the air mass measured
by the MAF with the projected air mass as it is cal-
culated by the ECM in consideration of various influ-
encing conditions. It is the air flow drift
compensation that gives the MAF air mass measure-
ment the precision needed to use it for the function
mentioned above. The high precision of the MAF
measurement enables the calculation of the actual
injection quantity from the measured air mass and
from the oxygen sensor signal in order to correct
injection quantity. The MAF signal can also be used
as a input parameter for the smoke limiter.
REMOVAL
(1) Disconnect the negative battery cable.
(2) Disconnect the ECM harness connectors (Fig.
4).
(3) Grasp ECM and pull down firmly to release
ECM from the retaining bracket tensioning springs
(Fig. 4).
INSTALLATION
NOTE: THE ECM MUST BE PROGRAMMED TO SUP-
PORT THE VEHICLE OPTIONS PACKAGE.
(1) Position the ECM into the guide of the retain-
ing bracket (Fig. 4).
(2) Carefully push the ECM in to the bracket until
the bracket tensioning springs engage (Fig. 4).
(3) Connect the ECM wiring harness connectors
(Fig. 4).
(4) Connect negative battery cable.
TRANSMISSION CONTROL
MODULE
DESCRIPTION
The transmission control module (TCM) receives,
processes and sends various digital and analog sig-
nals related to the automatic transmission. In addi-
tion, it processes information received from other
vehicle systems, such as engine torque and speed,
accelerator pedal position, wheel speed, kick-down
switch, traction control information, etc.
The TCM is located under the driver's seat and is
connected to other control modules via a CAN bus. It
controls all shift functions to achieve smooth shift
comfort in all driving situations considering:
²Vehicle speed.
²Transmission status.
Fig. 4 ECM
1 - BRACKET
2 - ECM
3 - BRACKET TENSIONING SPRINGS
8E - 6 ELECTRONIC CONTROL MODULESVA
N2 and N3 Speed Sensors
The N2 and N3 Input Speed Sensors are two Hall-
effect speed sensors that are mounted internally in
the transmission and are used by the TCM to calcu-
late the transmission's input speed. Since the input
speed cannot be measured directly, two of the drive
elements are measured. Two input speed sensors
were required because both drive elements are not
active in all gears.
CAN C Bus Indirect Input Signals
A 2.5-volt bias (operating voltage) is present on the
CAN C bus any time the ignition switch is in the
RUN position. Both the TCM and the ABS apply this
bias. On this vehicle, the CAN C bus is used for mod-
ule data exchange only. The indirect inputs used on
the NAG1 electronic control system are:
²Wheel Speed Sensors.
²Brake Switch.
²Engine RPM.
²Engine Temperature.
²Cruise Control Status.
²Gear Limit Request.
²Throttle Position - 0% at idle, 100% at WOT. If
open, TCM assumes idle (0% throttle opening).
²Odometer Mileage
²Maximum Effective Torque.
²Engine in Limp-In Mode/Mileage Where DTC
Was Set.
BRAKE TRANSMISSION SHIFT INTERLOCK (BTSI)
The BTSI solenoid prevents shifting out of the
PARK position until the ignition key is in the RUN
position and the brake pedal is pressed. The TCM
controls the ground while the ignition switch supplies
power to the BTSI solenoid. The PCM monitors the
brake switch and broadcasts brake switch status
messages over the CAN C bus. If the park brake is
depressed and there is power (Run/Start) to SLA, the
BTSI solenoid deactivates.
SHIFT SCHEDULES
The basic shift schedule includes up and down-
shifts for all five gears. The TCM adapts the shift
program according to driving style, accelerator pedal
position and deviation of vehicle speed. Influencing
factors are:
²Road Conditions.
²Incline, Decline and Altitude.
²Trailer Operation, Loading.
²Engine Coolant Temperature.
²Cruise Control Operation.
²Sporty Driving Style.
²Low and High ATF Temperature.
Upshift
To :1-2 2-3 3-4 4-5
Activat-
ed By
Sole-
noid:1-2/4-5 2-3 3-4 1-2/4-5
Shift
Point
(at
35.2%
of throt-
tle)17.8
km/h
(11.6
mph)32.1
km/h
(19.95
mph)67.5
km/h
(41.94
mph)73.8
km/h
(45.86
mph)
Down-
shift
From:5-4 4-3 3-2 2-1
Activat-
ed By
Sole-
noid:1-2/4-5 3-4 2-3 1-2/4-5
Shift
Point55.7
km/h
(34.61
mph)40.5
km/h
(25.17
mph)24.4
km/h
(15.16
mph)15.1
km/h
(9.38
mph)
DOWNSHIFT SAFETY
Selector lever downshifts are not performed if inad-
missible high engine rpm is sensed.
ADAPTATION
To equalize tolerances and wear, an automatic
adaptation takes place for:
²Shift Time.
²Clutch Filling Time.
²Clutch Filling Pressure.
²Torque Converter Lock-Up Control.
Adaptation data may be stored permanently and to
some extent, can be diagnosed.
Driving Style Adaptation
The shift point is modified in steps based on the
information from the inputs. The control module
looks at inputs such as:
²vehicle acceleration and deceleration (calculated
by the TCM).
²rate of change as well as the position of the
throttle pedal (fuel injection information from the
ECM).
²lateral acceleration (calculated by the TCM).
²gear change frequency (how often the shift
occurs).
Based on how aggressive the driver is, the TCM
moves up the shift so that the present gear is held a
8E - 8 ELECTRONIC CONTROL MODULESVA