tires MERCEDES-BENZ SPRINTER 2006 Service Manual

enable the HCU to perform the brake fluid manage-
ment control as the combination/proportioning
valves.
The Bosch 5.7 system uses the CAB/HCU/Pump
Motor to make an integral electronic/hydraulic unit
which shares data with other electronic modules on
the vehicle via the CAN C Bus network. To access
DTCs from the CAB, the DRBIIItuses the K-ABS
line located in the Data Link Connector (DLC).
3.3 BRAKE ASSIST SYSTEM (HBA)
The Brake Assist System (HBA) analyzes how
hard and fast the driver wants to brake. It monitors
the brake pressure via a pressure sensor. The
passenger car brake assist system uses a vacuum
booster solenoid. The Sprinter uses the hydraulic
control unit to develop the brake pressure.
3.4 TCS (ASR)
The primary function of the Traction Control System
is to reduce wheel slip and maintain traction at the
driven wheels when the road surfaces are slippery. The
Traction Control System reduces wheel slip by applying
the brake that has lost traction. The system is designed
to operate at speeds below 50 km/h (30 mph). The
engine's torque can be reduced by the ECM via the CAN
C Bus, if necessary. The TCS can be deactivated with
switch on the dash. The Traction Control System uses
the ABS to indicate spinning tires to enable the traction
control function. The TCS software is in the CAB.
The TCS (ASR) performs the following functions:
1. Engine power derate
2. Engine deceleration regulation. If the vehicle is
on a patch of ice, the simple action of releasing
the throttle is enough to cause the rear wheels to
slip. To avoid this, the throttle input is regulated
so power drops slowly instead of abruptly. The
engine power is reduced (decelerated) as neces-
sary.
3.5 ELECTRONIC BRAKE DISTRIBUTION
(EBD)
The system was enhanced and eliminates the
need for the ALB system (load sensing valve). All
ESP equipped models will not have ALB. The EBV
system self-adapts to operating conditions. It de-
tects the vehicle's payload when the vehicle starts
and pulls away. Based on the acceleration rate
when the vehicle first pulls away from a standstill,
the system is able to calculate the actual payload.
This is a rough estimate which is used initially.
Later on, the system gathers more precise informa-
tion by monitoring the brake pressure and wheel
speed and negative slip when the driver applies thebrakes. The system will then produce a more accu-
rate calculation of payload depending on brake
retardation. The adaptation is erased when the
ignition is switched off. A new adaptation will occur
on the next driving cycle. By default, the system
acts upon the vehicle as if in an unloaded condition
(safe mode).
Once a new driving cycle begins with the vehicle
in a fully loaded condition (without having gathered
more precise information) the system will detect
ABS actuation in the front wheels and will allow
enough pressure to be applied to the rear axle, to an
extent where the wheels are just about to lock up
(maximum braking possible).
The system calculates the braking force at the
front and rear axles. If the driver applies the brakes
gently and then realizes he needs to apply the
brakes further, the EBV allows the proper pressure
to be applied to the front and rear brakes.
The EBV also contains a feature called ªcorner
brake systemº (CBS) which operates when the ve-
hicle is braked while cornering to avoid a possible
oversteering condition. The EBV monitors the
wheel speed of both rear wheels to detect when the
vehicle is cornering and allows precise brake pres-
sure application to the front and rear brakes. Also
when the brakes are applied during cornering, the
outer wheels get more of the vehicle's weight while
the inner wheels get less weight and could lose
traction (wheel lock up). The EBV system splits the
pressure between left and right sides in addition to
front and rear brakes.
3.6 VEHICLE CONTROLLING (FZR)
Vehicle controlling (FZR)requires additional
sensors to operate. The term ESP refers to the
software of the system. The term FZR refers to the
system controller. The TCS (ASR) system requires
wheel speed sensors to monitor wheel slip and CAN
bus communications to regulate engine power. In
addition to these inputs, the vehicle controlling
(FZR) requires a steering angle sensor, and a lateral
acceleration/yaw rate sensor.
The ESP system does not take the vehicle load
into account. Instead, the coefficient of friction is
calculated in a 20 millisecond period, where the
controller measures the rate at which the wheel
speed is decelerated, as brake pressure is applied to
the wheel.
3.7 SYSTEM COMPONENTS
²Controller Antilock Brake (CAB)
²Hydraulic Control Unit (HCU)
²Pump Motor
2
GENERAL INFORMATION

read opposite switch states.Note: The BS and
BLS are in the same switch housing.
BRAKE LAMP SWITCH (BLS):This switch pre-
pares the CAB for a possible antilock event. The
CAB uses an output state voltage from the BLS
when the brake pedal is either depressed/released.
The Fused Ignition Switch Output circuit supplies
12 volts to the BLS. A depressed brake pedal will
close the BLS circuit and the BLS Output circuit
supplies 12 volts at the CAB. When the driver
releases the brake pedal, the BLS Output circuit
voltage drops to 0 volts and the CAB senses the
brake pedal state. This tells the CAB what position
the brake pedal is currently in to make an ABS
event possible. When using the DRBIIItin Inputs/
Outputs, the BS and BLS will read opposite switch
states.Note: The BS and BLS are in the same
switch housing.
TRACTION CONTROL SYSTEM SWITCH
(TCSS):This switch signals the CAB to either turn
ON or OFF the TCS. The driver can toggle the
TCSS, which receives 12 volts from the D (+) Relay
Output circuit. Depending on the position of the
TCSS, open or closed, the CAB receives the TCSS
state voltage on the TCS Switch Sense circuit.
When 12 volts are applied to the TCS Switch Sense
circuit, the TCS is OFF. When no voltage is present,
the TCS is ON.
WHEEL SPEED SENSORS AND TONE
WHEELS:The Bosch 5.7 system uses one passive
WSS on each wheel. The sensor measures the wheel
speed by monitoring a rotating tone wheel. As the
teeth of the tone wheel move through the magnetic
field of the sensor an AC voltage and amperage is
generated. This signal frequency increases or de-
creases proportionally to the speed of the wheel.
The CAB monitors this signal to check for a sudden
change in single or multiple wheel decelerations. If
the deceleration of one or more wheels is not within
a predetermined amount, the CAB takes control for
antilock action through the HCU. Each WSS has a
magnetic inductive pick up coil (WSS) that is
mounted to a fixed component. There is an air gap
between the tone wheel and the speed sensor as-
sembly. Diagnostically, the coils of the Wheel Speed
Sensors have the same amount of resistance. When
measured across the CAB harness connector termi-
nals, the resistance should be between 1100 - 1800
ohms. Refer to service manual for WSS replacement
and air gap specifications.
Correct ABS operation is dependent on Tone
Wheel speed signal from the WSS. The vehicle
wheels and tires should all be the same size and
type to get accurate signals. In addition, all tires
should be at recommended tire pressures.3.7.5 SELF TESTS
The system software includes several self tests
that are performed every time the ignition is turned
on and the vehicle is driven. Some of the self tests
occur immediately, while others occur under normal
driving conditions while not in antilock operation.
The CAB checks continuously for a missing or
erratic WSS signals/circuits, tone wheels, solenoids,
pump motor or solenoid relay by performing several
tests such as: dynamic, static, ohmic, voltage drop,
and timed response. If any component exhibits a
fault during testing, the CAB will request to illumi-
nate the ABS and TCS warning indicators.
As an additional check of the ESP system, a road
test procedure is available on the DRBIIIt. This
test should be carried out when any ESP component
is replaced in order to ensure proper function. Since
the wheel speed sensors are required inputs to the
ESP, this test should also be performed if the wheel
speed sensors are replaced.
First, the brakes are applied with the vehicle
stationary. Then, the vehicle is driven at approxi-
mately 6 MPH. The driver has to make left and
right turns, with a minimum 90 degree steering
turning angle. If the indicator lamp goes out, every-
thing is in order. If the lamp remains illuminated,
the DRBIIItwill display the fault codes that are
causing the test to fail. The road test function is set
in the ESP control module, and can only be deacti-
vated once there are no more fault codes detected.
The Steering Angle Sensor must be initialized. A
procedure is carried out using the DRBIIItto
ensure that the module detects the exact position of
the sensor. The sensor must be calibrated any time
wheel alignment is changed, the steering column is
removed and re-installed, or the sensor is replaced.
3.8 USING THE DRBIIIT
Refer to the DRBIIItuser 's guide for instructions
and assistance with reading diagnostic trouble
codes, erasing diagnostic trouble codes and other
DRBIIItfunctions.
3.9 DRBIIITERROR MESSAGES
Under normal operation, the DRBIIItwill dis-
play one of only two error messages:
Ð User-Requested WARM Boot or User-Requested
COLD Boot.
If the DRBIIItshould display any other error
message, record the entire display and call the
STAR Center for information and assistance. This
is a sample of such an error message display:
4
GENERAL INFORMATION

Symptom:
DRIVE TEST ERROR
POSSIBLE CAUSES
INTERMITTENT DRIVE TEST ERROR DTC
STEERING COMPONENT INSPECTION
LATERAL ACCELERATION SENSOR CIRCUIT SHORT TO VOLTAGE
LATERAL ACCELERATION SENSOR CIRCUIT SHORT TO GROUND
LATERAL ACCELERATION SENSOR CIRCUIT OPEN
LATERAL ACCELERATION SENSOR
ANTI-LOCK BRAKE CONTROLLER
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Turn the ignition on.
With the DRBIIIt, read DTCs. Record DTC information.
NOTE: If any other DTC is set along with this DTC, diagnose the other
DTC(s) first.
NOTE: Electromagnetic (radio) interference can cause an intermittent
system malfunction by interrupting communication between the sensor
and the CAB.
With the DRBIIIt, erase DTCs.
With the DRBIIIt, perform the road test procedure in accordance with the Service
Information.
With the DRBIIIt, read DTCs.
NOTE: Failure to perform the road test procedure properly can cause this
DTC to set.
NOTE: This DTC can only be cleared by a fault free road test.
Does this DTC reset?All
Ye s!Go To 2
No!Go To 7
2NOTE: When the vehicle is in a turn, the ESP compares the Steering Angle
Sensor value and the speed of the inner and outer wheels to determine if the
values are plausible.
Inspect the front end and steering components for damage or misalignment.
Inspect the Lateral Acceleration Sensor for correct mounting and installation.
Inspect the tires and wheels to make sure that they are the correct size. All tires must
be the same size.
Were any problems found?All
Ye s!Repair or replace components as necessary in accordance with the
Service Information.
No!Go To 3
29
BRAKES (CAB)

Symptom:
INCORRECT TONE WHEEL
When Monitored and Set Condition:
INCORRECT TONE WHEEL
When Monitored: Ignition On - Continuously
Set Condition: When continuous ABS control is active for one minute on one or more
wheels OR interference on one or more wheels OR deviation of two wheel speeds at either
side of vehicle by 6 km/h (4 mph) or at the front axle by 10 km/h (7 mph). If at least one
wheel is 5 km/h (3 mph) or less, a wheel speed deviation of adjoining wheels of 12 km/h (8
mph) is allowed.
POSSIBLE CAUSES
INTERMITTENT INCORRECT TONE WHEEL DTC
INCORRECT TIRES ON VEHICLE
TIRE CIRCUMFERENCES NOT MATCHING
WHEEL SPEED SENSOR CIRCUIT SHORT TO VOLTAGE
INCORRECT TONE WHEEL
WHEEL SPEED SENSOR CIRCUIT SHORT TO GROUND
DAMAGED WHEEL BEARING
WHEEL SPEED SENSOR CIRCUIT OPEN
DAMAGED BRAKE LININGS/COMPONENTS
WHEEL SPEED SENSOR CIRCUITS SHORTED TOGETHER
WHEEL SPEED SENSOR
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, read DTCs.
With the DRBIIIt, erase DTCs.
Turn the ignition off.
Turn the ignition on.
Road test the vehicle.
During the road test, drive the vehicle above 100 km/h (62 mph) for at least 3 minutes
and perform several stops and Antilock stops.
Stop the vehicle.
With the DRBIIIt, read DTCs.
Does the DRBIIItdisplay INCORRECT TONE WHEEL?All
Ye s!Go To 2
No!Go To 13
32
BRAKES (CAB)

Symptom List:
LATERAL ACCELERATION SENSOR CIRCUIT
LATERAL ACCELERATION SENSOR IMPLAUSIBLE
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be LATERAL ACCELERATION
SENSOR CIRCUIT.
POSSIBLE CAUSES
LATERAL ACCELERATION SENSOR CIRCUIT INTERMITTENT DTC
STEERING COMPONENT INSPECTION
LATERAL ACCELERATION SENSOR CIRCUIT SHORT TO VOLTAGE
LATERAL ACCELERATION SENSOR CIRCUIT SHORT TO GROUND
LATERAL ACCELERATION SENSOR CIRCUIT OPEN
LATERAL ACCELERATION SENSOR
ANTI-LOCK BRAKE CONTROLLER
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Turn the ignition on.
With the DRBIIIt, read DTCs. Record DTC information.
NOTE: If a system undervoltage or overvoltage DTC is set along with this
DTC, diagnose the system voltage DTC first.
NOTE: Electromagnetic (radio) interference can cause an intermittent
system malfunction by interrupting communication between the sensor
and the CAB.
With the DRBIIIt, erase DTCs.
Road test the vehicle and perform several braking maneuvers.
With the DRBIIIt, perform the road test procedure.
With the DRBIIIt, read DTCs.
Does this DTC reset?All
Ye s!Go To 2
No!Go To 7
2NOTE: When the vehicle is in a turn, the ESP compares the Steering Angle
Sensor value and the speed of the inner and outer wheels to determine if the
values are plausible.
Inspect the front end and steering components for damage or misalignment.
Inspect the Lateral Acceleration Sensor for correct mounting and installation.
Inspect the tires and wheels to make sure that they are the correct size. All tires must
be the same size.
Were any problems found?All
Ye s!Repair or replace components as necessary in accordance with the
Service Information.
No!Go To 3
36
BRAKES (CAB)

Symptom:
STEERING ANGLE SENSOR GREATER THAN 720 DEGREES
POSSIBLE CAUSES
STEERING ANGLE SENSOR INTERMITTENT DTC
STEERING COMPONENT INSPECTION
STEERING ANGLE SENSOR
TEST ACTION APPLICABILITY
1NOTE: If a system undervoltage or overvoltage DTC is set along with this
DTC, diagnose the system voltage DTC first.
NOTE: Electromagnetic (radio) interference can cause an intermittent
system malfunction by interrupting communication between the sensor
and the CAB.
NOTE: The Steering Angle Sensor is very sensitive to changes due to
alignment problems. The sensor must be recalculated using the DRBIIItif
alignment has been changed by more than 5 degrees.
Turn the ignition on.
With the DRBIIIt, erase DTCs.
Move the Steering Wheel from stop to stop several times.
With the DRBIIIt, read DTCs.
Does this DTC reset?All
Ye s!Go To 2
No!Go To 3
2NOTE: When the vehicle is in a turn, the ESP compares the Steering Angle
Sensor value and the speed of the inner and outer wheels to determine if the
values are plausible.
Inspect the front end and steering components for damage or misalignment.
Inspect the steering column and Steering Angle Sensor for correct mounting and
installation.
Inspect the tires and wheels to make sure that they are the correct size. All tires must
be the same size.
Were any problems found?All
Ye s!Repair or replace components as necessary in accordance with the
Service Information.
No!Replace the Steering Angle Sensor in accordance with the Service
Information.
66
BRAKES (CAB)

TEST ACTION APPLICABILITY
3 The condition that set this DTC is not present at this time.
Monitor the DRBIIItwhile wiggle testing the related harness and connectors. Look
for any related parameters to change or for the DTC to reset.
Inspect the related harness and connectors.
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out, or corroded terminals.
Inspect the tires and wheels to make sure that they are the correct size. All tires must
be the same size.
Inspect the steering column and Steering Angle Sensor for correct mounting and
installation.
Inspect the front end and steering components for damage or misalignment.
Were any problems found?All
Ye s!Repair as necessary.
No!Test Complete.
67
BRAKES (CAB)
STEERING ANGLE SENSOR GREATER THAN 720 DEGREES ÐContinued

Symptom:
STEERING ANGLE SENSOR IMPLAUSIBLE VALUE
POSSIBLE CAUSES
STEERING ANGLE SENSOR INTERMITTENT DTC
STEERING COMPONENT INSPECTION
STEERING ANGLE SENSOR
TEST ACTION APPLICABILITY
1NOTE: If a system undervoltage or overvoltage DTC is set along with this
DTC, diagnose the system voltage DTC first.
NOTE: Electromagnetic (radio) interference can cause an intermittent
system malfunction by interrupting communication between the sensor
and the CAB.
NOTE: The Steering Angle Sensor is very sensitive to changes due to
alignment problems. The sensor must be recalculated using the DRBIIItif
alignment has been changed by more than 5 degrees.
Turn the ignition on.
With the DRBIIIt, erase DTCs.
With the DRBIIIt, recalculate the Steering Angle Sensor.
Move the Steering Wheel from stop to stop several times.
With the DRBIIIt, perform the road test procedure.
With the DRBIIIt, read DTCs.
Does this DTC reset?All
Ye s!Go To 2
No!Go To 3
2NOTE: When the vehicle is in a turn, the ESP compares the Steering Angle
Sensor value and the speed of the inner and outer wheels to determine if the
values are plausible.
Inspect the front end and steering components for damage or misalignment.
Inspect the steering column and Steering Angle Sensor for correct mounting and
installation.
Inspect the tires and wheels to make sure that they are the correct size. All tires must
be the same size.
Were any problems found?All
Ye s!Repair or replace components as necessary in accordance with the
Service Information.
No!Inspect the Steering Angle Sensor for proper installation. Inspect
the wiring and connectors. Repair as necessary. If no other
problems are found, replace the Steering Angle Sensor in accor-
dance with the Service Information.
70
BRAKES (CAB)

TEST ACTION APPLICABILITY
3 The condition that set this DTC is not present at this time.
Monitor the DRBIIItwhile wiggle testing the related harness and connectors. Look
for any related parameters to change or for the DTC to reset.
Inspect the related harness and connectors.
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out, or corroded terminals.
Inspect the tires and wheels to make sure that they are the correct size. All tires must
be the same size.
Inspect the steering column and Steering Angle Sensor for correct mounting and
installation.
Inspect the front end and steering components for damage or misalignment.
Were any problems found?All
Ye s!Repair as necessary.
No!Test Complete.
71
BRAKES (CAB)
STEERING ANGLE SENSOR IMPLAUSIBLE VALUE ÐContinued

Symptom:
STEERING ANGLE SENSOR IMPLAUSIBLE WHEEL SPEED
POSSIBLE CAUSES
STEERING ANGLE SENSOR INTERMITTENT DTC
STEERING COMPONENT INSPECTION
STEERING ANGLE SENSOR
TEST ACTION APPLICABILITY
1NOTE: If a system undervoltage or overvoltage DTC is set along with this
DTC, diagnose the system voltage DTC first.
NOTE: Electromagnetic (radio) interference can cause an intermittent
system malfunction by interrupting communication between the sensor
and the CAB.
NOTE: The Steering Angle Sensor is very sensitive to changes due to
alignment problems. The sensor must be recalculated using the DRBIIItif
alignment has been changed by more than 5 degrees.
Turn the ignition on.
With the DRBIIIt, erase DTCs.
Test drive the vehicle.
Using the DRBIIIt, perform the road test procedure.
With the DRBIIIt, read DTCs.
NOTE: If the ESP lamp remains illuminated after the test has completed, a
fault code will be set indicating the cause of the failure.
Does this DTC reset?All
Ye s!Go To 2
No!Go To 3
2NOTE: When the vehicle is in a turn, the ESP compares the Steering Angle
Sensor value and the speed of the inner and outer wheels to determine if the
values are plausible.
Inspect the front end and steering components for damage or misalignment.
Inspect the steering column and Steering Angle Sensor for correct mounting and
installation.
Inspect the tires and wheels to make sure that they are the correct size. All tires must
be the same size.
Inspect the left and right Wheel Speed Sensors to make sure they are connected
correctly, i.e. left harness connected to left sensor, etc.
Were any problems found?All
Ye s!Repair or replace components as necessary in accordance with the
Service Information.
No!Replace the Steering Angle Sensor in accordance with the Service
Information.
72
BRAKES (CAB)