Mercedes-Benz Sprinter / Dodge Sprinter. Manual — part 205

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:

• Fuel Supply System

• Injected Quantity Control

• Emission Control System

• Charge Pressure Control

• Cruise Control

• A/C Compressor Shut-Off

• Pre-Heating Output Relay for the Glow Plugs

• Vehicle Theft

• Air Bag

• Monitors inputs/outputs, checks plausibility and

stores faults

• Share information with other control modules

• Diagnosis
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)

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ELECTRONIC CONTROL MODULES

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ECM Control Strategy The engine control module

is involved with a variety of functions such as: (Fig.
3)

• Individual injector activation

• Engine idle speed control to ensure smooth

engine idling independent of engine load

• Ride 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

• Constant RPM (high idle feature) for ambulance

vehicle bodies equipped with electrical appliances

• Starter control, immobilizer, cruise control, kick

down, air conditioner

• Maintenance computer ASSYST (optional)

• Glow plug for pre-heating, post heating and

intermittent heating

• Error code memory/diagnostics, communication

interface for diagnosis and handling the fault codes

• The 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

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ELECTRONIC CONTROL MODULES

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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).

• The 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

• Individual 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

• A relay is used for activating the electric in-tank

fuel pump

• Heated crankcase ventilation to ensure pressure

compensation even at low temperatures

• Improved boost pressure control using an elec-

tric variable nozzle turbine actuator with position
feed back

• Controlled fuel heating using the high pressure

pump closed-loop control

• Translation of the drive input received from the

accelerator pedal module which is equipped with
dual hall sensors

• Measurement of the intake air mass using new

mass air flow (MAF) sensor with increase precision
and extended measuring range

• O2 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

• Activation of the O2 sensor heater to burn off

deposits

• Full 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:

• Injection 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

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rate and boost pressure are adjusted to the actual
injection quantity.

• Injection 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

• Air-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:

• Vehicle speed.

• Transmission status.

Fig. 4 ECM

1 - BRACKET
2 - ECM
3 - BRACKET TENSIONING SPRINGS

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