MERCEDES-BENZ SPRINTER 2006 User Guide

TABLE OF CONTENTS - Continued
8.9VEHICLE THEFT SECURITY SYSTEM................................254
8.9.1SECURITY SYSTEM MODULE..............................254
8.9.2INTRUSION SENSORS....................................254
8.9.3SWITCHES..............................................255
8.9.4SIREN..................................................255
9.0 CONNECTOR PINOUTS................................................257
A/C AUXILIARY FAN....................................................257
AIR OUTLET TEMPERATURE SENSOR...................................257
AIRBAG CONTROL MODULE - YELLOW...................................257
AIRBAG SQUIB-DRIVER - YELLOW.......................................258
AIRBAG SQUIB-PASSENGER - YELLOW..................................258
AMBIENT TEMPERATURE SENSOR......................................258
AUTOMATIC TEMPERATURE CONTROL MODULE C1 - BROWN..............259
AUTOMATIC TEMPERATURE CONTROL MODULE C2.......................259
AUXILIARY HEATER CONTROL..........................................259
BLOWER MOTOR RESISTOR BLOCK.....................................259
BLOWER MOTOR-FRONT - BLACK.......................................260
C205 - YELLOW (DASH SIDE)...........................................260
C205 - YELLOW (MAIN BODY SIDE)......................................260
CENTRAL TIMER MODULE C1 - PINK.....................................260
CENTRAL TIMER MODULE C2 - LT. GREEN...............................261
CIRCULATION PUMP (CABIN HEATER MODULE)...........................261
CIRCULATION PUMP (REST SYSTEM)....................................261
CIRCULATION PUMP DIODE............................................261
CLOCKSPRING C2 - YELLOW...........................................262
CONTROLLER ANTILOCK BRAKE........................................262
CYLINDER LOCK SWITCH-DRIVER.......................................263
DATA LINK CONNECTOR - BLACK........................................263
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-DRIVER C1.................263
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-DRIVER C2.................263
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-LEFT SLIDING C1...........263
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-LEFT SLIDING C2...........264
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-PASSENGER C1............264
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-PASSENGER C2............264
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-REAR C1...................264
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-REAR C2...................264
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-RIGHT SLIDING C1..........265
DOOR LOCK MOTOR/AJAR SWITCH ASSEMBLY-RIGHT SLIDING C2..........265
DOSING PUMP........................................................265
ENGINE CONTROL MODULE C1 (EXCEPT OBD) - BLACK...................265
ENGINE CONTROL MODULE C2 (EXCEPT OBD) - BLACK...................266
ENGINE CONTROL MODULE C2 (OBD)...................................267
ENGINE CONTROL MODULE C3 (EXCEPT OBD) - BLACK...................268
EVAPORATOR TEMPERATURE SENSOR..................................269
FUEL LEVEL SENSOR..................................................269
FUSES (FUSE BLOCK NO. 1)............................................271
FUSE BLOCK NO. 1 C1.................................................271
FUSE BLOCK NO. 1 C2.................................................271
FUSE BLOCK NO. 1 C3 - BLACK.........................................272
FUSE BLOCK NO. 1 C4 - BLACK.........................................272
FUSE BLOCK NO. 1 C5 - BLACK.........................................272
vi

TABLE OF CONTENTS - Continued
FUSES (FUSE BLOCK NO. 2)............................................274
FUSES (FUSE BLOCK NO. 3)............................................276
FUSES (FUSE/RELAY BLOCK)...........................................278
HOOD AJAR SWITCH - BLACK...........................................278
HORN (VTSS).........................................................278
IGNITION LOCK SWITCH - BLACK........................................278
INSTRUMENT CLUSTER C1.............................................279
INSTRUMENT CLUSTER C2 - WHITE.....................................279
INTRUSION SENSOR NO. 1 - BLACK.....................................279
INTRUSION SENSOR NO. 2 - BLACK.....................................279
INTRUSION SENSOR NO. 3 - BLACK.....................................280
MASTER DOOR LOCK SWITCH..........................................280
PANIC ALARM SWITCH - BLACK.........................................280
FUSES (PDC).........................................................281
RADIO C1 - BLACK....................................................282
RADIO C2............................................................282
RECIRCULATED AIR SOLENOID VALVE...................................282
REFRIGERANT PRESSURE SENSOR.....................................282
A/C AUXILIARY FAN RELAY (RELAY BLOCK)...............................284
CIRCULATION PUMP RELAY-CABIN HEATER MODULE (RELAY BLOCK).......284
D+ RELAY NO. 2 (RELAY BLOCK)........................................284
FAN STAGE 1 RELAY (RELAY BLOCK)....................................284
OPTIONAL EQUIPMENT RELAY (RELAY BLOCK)...........................284
REMOTE KEYLESS ENTRY ANTENNA....................................284
SEAT BELT SWITCH...................................................284
SEAT BELT TENSIONER-DRIVER - YELLOW...............................285
SEAT BELT TENSIONER-PASSENGER - YELLOW...........................285
SECURITY SYSTEM MODULE C1 - BROWN...............................285
SECURITY SYSTEM MODULE C2 - LT. GREEN.............................286
SENTRY KEY REMOTE ENTRY MODULE (SKREEM)........................286
SHIFTER ASSEMBLY - BLACK...........................................286
SIREN - BLACK.......................................................286
STEERING ANGLE SENSOR............................................287
TOWING/INTRUSION SENSOR ON/OFF SWITCH...........................287
TRANSMISSION CONTROL MODULE C1 - BLACK..........................287
TRANSMISSION CONTROL MODULE C2 - BLACK..........................288
WATER CYCLE VALVE..................................................288
WINDOW DEFOGGER-LEFT REAR.......................................288
WINDOW DEFOGGER-RIGHT REAR......................................288
10.0 SCHEMATIC DIAGRAMS................................................289
10.1AIRBAG SYSTEM.................................................289
10.2COMMUNICATION................................................290
10.2.1COMMUNICATION K-LINES................................290
10.2.2CAN BUS NETWORK......................................291
10.3HEATING & A/C...................................................292
10.3.1AUTOMATIC TEMPERATURE CONTROL (ATC)................292
10.3.2CABIN HEATER MODULE (CHM)............................293
10.3.3HEATER BOOSTER MODULE (HBM).........................294
10.4INSTRUMENT CLUSTER...........................................295
vii

TABLE OF CONTENTS - Continued
10.5POWER DOOR LOCKS/RKE........................................296
10.5.1FRONT DOORS..........................................296
10.5.2SLIDING AND REAR DOORS...............................297
10.5.3SWITCH AND MISCELLANEOUS CIRCUITS...................298
10.6VEHICLE THEFT SECURITY SYSTEM................................299
10.7RAIN SENSOR SYSTEM...........................................300
11.0 CHARTS AND GRAPHS................................................301
11.1EVAP TEMP SENSOR RESISTANCE TO TEMPERATURE
SPECIFICATIONS.................................................301
11.2AIR OUTLET TEMP SENSOR RESISTANCE TO TEMPERATURE
SPECIFICATIONS.................................................301
11.3WIPER SWITCH/WASHER SWITCH VOLTAGE SIGNALS................302
viii

1.0 INTRODUCTION
The procedures contained in this manual include
all the specifications, instructions and graphics
needed to diagnose Sprinter body system problems.
The diagnostics in this manual are based on the
failure condition or symptom being present at the
time of diagnosis.
Please follow the recommendations below when
choosing your diagnostic path.
1. First make sure the DRBIIItis communicating
with the appropriate modules; i.e., if the
DRBIIItdisplays a ``No Response'' or a ``Bus6
Signals Open'' condition, you must diagnose that
first.
2. Read DTC's (diagnostic trouble codes) with the
DRBIIIt.
3. If no DTC's are present, identify the customer
complaint.
4. Once the DTC or customer complaint is identi-
fied, locate the matching test in the Table of
Contents and begin to diagnose the symptom.
All component location views are in Section 8.0.
All connector pinouts are in Section 9.0. All sche-
matics are in Section 10.0. All Charts and Graphs
are in Section 11.0.
An * placed before the symptom description indi-
cates a customer complaint without a DTC.
When repairs are required, refer to the appropri-
ate service information for the proper removal and
repair procedure.
Diagnostic procedures change every year. New
diagnostic systems may be added: carryover sys-
tems may be enhanced. READ THIS MANUAL
BEFORE TRYING TO DIAGNOSE A VEHICLE
DIAGNOSTIC TROUBLE CODE. It is recom-
mended that you review the entire manual to be-
come familiar with all the new and changed diag-
nostic procedures.
This book reflects many suggested changes from
readers of past issues. After using this book, if you
have any comments or suggestions, please fill out
the form in the back of this book and mail it back to
us.
1.1 SYSTEM COVERAGE
This diagnostic procedures manual covers all
Sprinter vehicles.
1.2 SIX-STEP TROUBLESHOOTING
PROCEDURE
Diagnosis of the body system is done in six basic
steps:
²verification of complaint
²verification of any related symptoms
²symptom analysis
²problem isolation
²repair of isolated problem
²verification of proper operation
2.0 IDENTIFICATION OF
SYSTEM
The vehicle systems that are part of the ``body''
system are:
²Airbag
²Automatic Temperature Control
²Communication
²Instrument Cluster
²Power Door Locks/RKE
²Vehicle Theft Security System (VTSS)
²Wiper/Rain Sensor
3.0 SYSTEM DESCRIPTION AND
FUNCTIONAL OPERATION
The body system on the Sprinter consists of a
combination of modules that communicate with
each other using the CAN Bus (controller area
network). Through the CAN Bus, information about
the operation of vehicle components and circuits is
relayed quickly to the appropriate modules. Since
the CAN bus network is for intermodule communi-
cation only, the DRBIIItutilizes K-Lines to estab-
lish communications with each module. It is impor-
tant to note the CAN bus circuits are by no means
tied to the K-Lines. They are completely separate
from each other. For additional information on the
CAN bus and the K-Lines, refer to the Communi-
cation section of this general information.
3.1 AIRBAG SYSTEM
The Sprinter Airbag System contains the follow-
ing components:
²Airbag Control Module (ACM)
²Airbag Warning Indicator (SRS)
²Driver Airbags
²Clockspring
²Passenger Airbag
²Driver Seat Belt Tensioners
²Passenger Seat Belt Tensioners
The Airbag Control Module (ACM) has five major
functions: onboard diagnostics, determine the se-
verity of impacts, squib deployment and Accident
Response, K-Line communications. The ACM is
1
GENERAL INFORMATION

secured to the floor under the Driver seat and
receives power from the Fuse Block No. 1. When-
ever the ignition key is turned to the run or start
position, the ACM performs a system test. The ACM
cannot be repaired or adjusted.
The microprocessor in the ACM monitors the
internal and external airbag system electrical cir-
cuits to determine the system readiness. When a
monitored system is determine to be out of range,
the ACM will set both active and stored diagnostic
trouble codes (DTC). The ACM also contains an
energy-storage capacitor. This capacitor stores
enough electrical energy to deploy the front airbag
components for two seconds following a battery
disconnect or failure during an impact.
The Accelerometer in the ACM is used to sense
the rate of vehicle deceleration, provide verification
of the direction and severity of an impact. When the
preprogrammed conditions are met, the ACM sends
an electrical signal to deploy the appropriate front
airbag system components and a deployment noti-
fication.
To provide an accident response notification, the
ACM is hardwired to the Central Timer module
(CTM) and Engine Control Module (ECM). When a
deployment occurs the ACM provides a 50ms 10.0
volt pulse to the CTM and ECM. When the Accident
Report notification signal is received the CTM un-
locks the door locks and the ECM stalls the engine.
The Accident signal will set a DTC in the CTM and
the door locks will not work until the DTC has been
erased. The ECM will set a DTC if the Accident
Report circuit is shorted to battery voltage. The
ACM saves the deployment record and after three
deployments the ACM must be replaced. The
DRBIIItcan be used to test the Accident Report
Notification feature: select the SYSTEM TEST from
the ACM main menu. Then select the Analog Crash
Output System Test.
The ACM is hardwired to the Instrument Cluster
(MIC) to control Warning Indicator (SRS indicator).
When DTCs becomes activate, the ACM illuminates
the Warning Indicator by pulling the indicator
circuit low. The SRS indicator is the only point at
which the customer can observe symptoms of a
system malfunction.
As part of the system test the ACM illuminates
the Warning Indicator on for 4.0 second bulb test.
After the lamp check, if the indicator turns off, it
means that the ACM has checked the system and
found it to be free of discernible malfunctions.
NON-CRITICAL DTCs
If the lamp comes on and stays on for a period
longer than 4.0 seconds (about 10.0 seconds) is
usually a stored DTC (intermittent problem) in the
system.
CRITICAL DTCs
DTCs that could lead to a condition where the
safety devises may not deploy or incorrectly deploy.
In the event of such a DTC, the safety of the vehicle
occupants can no longer be guaranteed. If the lamp
remains on, there could be an active DTC in the
system. Some DTCs, Internal Module and squib
DTCs, will keep the indicator illuminated even if
the codes are no longer active.
ACM NOT CONFIGURED FOR PASSENGER
AIRBAG AND TENSIONER
If after replacing the ACM the Airbag Warning
Indicator flashes continuously the ACM must be
configured for the Passenger Airbag and Tensioner.
Select Miscellaneous from the ACM main menu and
configure the Passenger Airbag Tensioner squibs.
WARNING:THE AIRBAG SYSTEM IS A
SENSITIVE, COMPLEX ELECTROMECHANICAL
UNIT. BEFORE ATTEMPTING TO DIAGNOSE OR
SERVICE ANY AIRBAG SYSTEM OR RELATED
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENTS YOU MUST
FIRST DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE. WAIT
TWO MINUTES FOR THE SYSTEM CAPACITOR
TO DISCHARGE BEFORE FURTHER SYSTEM
SERVICE. THIS IS THE ONLY SURE WAY TO
DISABLE THE AIRBAG SYSTEM. FAILURE TO
DO THIS COULD RESULT IN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
WARNING: TO AVOID PERSONAL INJURY OR
DEATH, NEVER STRIKE OR KICK THE
AIRBAG CONTROL MODULE, AS IT CAN
DAMAGE THE IMPACT SENSOR OR AFFECT
ITS CALIBRATION.
WARNING: IF AN AIRBAG CONTROL
MODULE IS ACCIDENTALLY DROPPED
DURING SERVICE, THE MODULE MUST BE
SCRAPPED AND REPLACED WITH A NEW
UNIT. FAILURE TO TAKE THE PROPER
PRECAUTIONS COULD RESULT IN
ACCIDENTAL AIRBAG DEPLOYMENT AND
PERSONAL INJURY OR DEATH.
3.1.1 DRIVER AIRBAG
The airbag protective trim cover is the most
visible part of the driver side airbag system. The
airbag is mounted directly to the steering wheel.
Located under the trim cover are the airbag cushion
and the airbag cushion supporting components.
2
GENERAL INFORMATION

When supplied with the proper electrical signal, the
inflator discharged the gas directly into the cush-
ion. The airbag cannot be repaired, and must be
replaced if deployed or in any way damaged.
WARNING: THE DRIVER AIRBAG MODULE
CONTAINS ARGON GAS PRESSURIZED TO
OVER 17236.89 Kpa (2500 PSI). DO NOT
ATTEMPT TO DISMANTLE AN AIRBAG
MODULE OR TAMPER WITH ITS INFLATOR.
DO NOT PUNCTURE, INCINERATE, OR
BRING INTO CONTACT WITH ELECTRICITY.
DO NOT STORE AT TEMPERATURE
EXCEEDING 93ÉC (200ÉF). REPLACE AIRBAG
SYSTEM COMPONENTS ONLY WITH PARTS
SPECIFIED IN THE CHRYSLER MOPAR
PARTS CATALOG. SUBSTITUTE PARTS MAY
APPEAR INTER-CHANGEABLE, BUT
INTERNAL DIFFERENCES MAY RESULT IN
INFERIOR OCCUPANT PROTECTION. THE
FASTENERS, SCREWS, AND BOLTS
ORIGINALLY USED FOR THE AIRBAG
SYSTEM COMPONENTS HAVE SPECIAL
COATINGS AND ARE SPECIFICALLY
DESIGNED FOR THE AIRBAG SYSTEM. THEY
MUST NEVER BE REPLACED WITH ANY
SUBSTITUTES. ANY TIME A NEW FASTENER
IS NEEDED, REPLACE IT WITH THE
CORRECT FASTENERS PROVIDED IN THE
SERVICE PACKAGE OR SPECIFIED IN THE
MOPAR PARTS CATALOG. FAILURE TO
TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG
DEPLOYMENT AND PERSONAL INJURY OR
DEATH.
3.1.2 CLOCKSPRING
The clockspring is mounted on the steering col-
umn under the steering wheel. This assembly con-
sists of a plastic housing which contains a flat,
ribbon-like, electrically conductive tape that winds
and unwinds with the steering wheel rotation. The
clockspring is used to maintain a continuous elec-
trical circuit between the instrument panel wiring
and the driver airbag and the horn. The clockspring
must be properly centered when it is reinstalled on
the steering column following any service proce-
dure, or it could be damaged. The clockspring can-
not be repaired and it must be replaced.
3.1.3 PASSENGER AIRBAG
The Passenger Airbag is optional equipment.
When supplied with the proper electrical signal the
passenger airbag inflator discharges the gas di-rectly into the cushion. The airbag module cannot
be repaired, and must be replaced if deployed or in
any way damaged.
WARNING: THE PASSENGER AIRBAG
MODULE CONTAINS ARGON GAS
PRESSURIZED TO 17236.89 Kpa (2500 PSI).
DO NOT ATTEMPT TO DISMANTLE AN
AIRBAG MODULE OR TAMPER WITH ITS
INFLATOR. DO NOT PUNCTURE,
INCINERATE, OR BRING INTO CONTACT
WITH ELECTRICITY. DO NOT STORE AT
TEMPERATURE EXCEEDING 93ÉC (200ÉF).
REPLACE AIRBAG SYSTEM COMPONENTS
ONLY WITH PARTS SPECIFIED IN THE
MOPAR PARTS CATALOG. SUBSTITUTE
PARTS MAY APPEAR INTER-CHANGEABLE,
BUT INTERNAL DIFFERENCES MAY RESULT
IN INFERIOR OCCUPANT PROTECTION. THE
FASTENERS, SCREWS, AND BOLTS
ORIGINALLY USED FOR THE AIRBAG
SYSTEM COMPONENTS HAVE SPECIAL
COATINGS AND ARE SPECIFICALLY
DESIGNED FOR THE AIRBAG SYSTEM. THEY
MUST NEVER BE REPLACED WITH ANY
SUBSTITUTES. ANY TIME A NEW FASTENER
IS NEEDED, REPLACE IT WITH THE
CORRECT FASTENERS PROVIDED IN THE
SERVICE PACKAGE OR SPECIFIED IN THE
MOPAR PARTS CATALOG. FAILURE TO
TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG
DEPLOYMENT AND PERSONAL INJURY OR
DEATH.
3.1.4 SEAT BELT TENSIONERS
Front seat belt systems incorporate a Driver and
optional Passenger Seat Belt Tensioner Retractors.
At the onset of an impact event each tensioner uses
a pyrotechnic device, which is triggered simulta-
neously with the front airbags, to rapidly retract
the seat belts. With the slack removed, the occu-
pant's forward motion in an impact will be reduced
as will the likelihood of contacting interior compo-
nents. After an impact that deploys the airbag, the
seat belt tensioner assembly must be replaced. The
ACM module monitors the Seat Belt Tensioners
circuit resistance and reports active and stored
DTCs if any problem is found. Follow all of the
safety procedures when servicing tensioner.
3.1.5 SPECIAL TOOLS
Airbag load tools 8310 and 8443 are used in some
airbag diagnostic test. The load tools contain fixed
resistive loads, jumpers and adapters. The fixed
3
GENERAL INFORMATION

loads are connected to cables and mounted in a
storage case. The cables can be directly connected to
some airbag system connectors. Jumpers are used
to convert the load tool cable connectors to the other
airbag system connectors. The adapters are con-
nected to the module harness connector to open
shorting clips and protect the connector terminal
during testing. When using the load tool follow all of
the safety procedures in the service information for
disconnecting airbag system components. Inspect
the wiring, connector and terminals for damage or
misalignment. Substitute the airbag load tool in
place of a Driver or Passenger Airbag, seat belt
tensioner, clockspring (use a jumper if needed).
Then follow all of the safety procedures in the
service information for connecting airbag system
components. Read the module active DTCs. If the
module reports NO ACTIVE DTCs the defective
components has been removed from the system and
should be replaced. If the DTC is still active, con-
tinue this process until all components in the circuit
have been tested. Then disconnect the module con-
nector and connect the matching adapter to the
module connector. With all airbags disconnected
and the adapter installed the squib wiring can be
tested for open and shorted conditions.
3.1.6 DIAGNOSTIC TROUBLE CODES
Airbag diagnostic trouble codes consist of active
and stored codes. If more than one code exists,
diagnostic priority should be given to the active
codes. Each diagnostic trouble code is diagnosed by
following a specific testing procedure. The diagnos-
tic test procedures contain step-by-step instructions
for determining the cause of the trouble codes. It is
not necessary to perform all of the tests in this book
to diagnose an individual code. Always begin by
reading the diagnostic trouble codes with the
DRBIIIt. This will direct you to the specific test(s)
that must be performed. In certain test procedures
within this manual, diagnostic trouble codes are
used as a diagnostic tool.
3.1.6.1 ACTIVE CODES
If the lamp remains on, there could be an active
DTC in the system. The code becomes active as soon
as the malfunction is detected or key-on, whichever
occurs first. An active trouble code indicates an
on-going malfunction. This means that the defect is
currently there every time the airbag control mod-
ule checks that circuit or component. Some DTCs,
Internal Module and squib DTCs, will keep the
indicator illuminated even if they are no longer
active. If the lamp is on and no active codes are
present, cycling the ignition switch off and then on
will refresh the lamp state. It is impossible to erase
an active code.
3.1.6.2 STORED CODES
Airbag codes are automatically stored in the
ACM's memory as soon as the malfunction is de-
tected. A stored code indicates there was an active
code present at some time. Stored diagnostic trou-
ble code will remain stored until erased by the DRB.
If a malfunction is not active while performing a
diagnostic test procedure, the active code diagnostic
test will not locate the source of the problem. In this
case, the stored code can indicate an area to inspect.
Maintain a safe distance from all airbags while
performing the following inspection. If no obvious
problems are found, erase stored codes, and with
the ignition on wiggle the wire harness and connec-
tors, rotate the steering wheel from stop to stop.
Recheck for codes periodically as you work through
the system. This procedure may uncover a malfunc-
tion that is difficult to locate.
3.2 COMMUNICATION
3.2.1 COMMUNICATION K-LINES
The K-Lines are a group of circuits that connect
each control module to the Data Link Connector
(DLC). Each control module is connected to the DLC
with a single K-Line. The DRBIIItuses the K-Line
to communicate with each control module. With the
use of the K-Lines the DRBIIItis able to read each
control modules DTCs, sensor displays, I/Os etc. If
DRBIIItcommunications with a particular control
module is lost, one of the possible causes could be a
fault in the module's K-Line.
NOTE: It is important to note the DRBIIIT
uses the K-Lines for diagnostic and
monitoring functions and is no way
connected to the CAN data bus network.
The following modules that use the K-line on this
vehicle are:
²Airbag Control Module (ACM)
²Automatic Temperature Control (ATC)
²Cabin Heater Module (CHM)
²Central Timer Module (CTM)
²Controller Antilock Brake (CAB)
²Engine Control Module (ECM)
²Heater Booster Module (HBM)
²Instrument Cluster (IC)
²Shifter Assembly (SA)
²Security System Module (SSM)
²Sentry Key Remote Entry Module (SKREEM)
²Transmission Control Module (TCM)
4
GENERAL INFORMATION

3.2.2 CAN BUS
The CAN bus (controller area network) is a data
bus system specifically design for inter module
communication on this vehicle. The CAN bus con-
sists of a special twisted two-core cable. Control
modules are connected to this9twisted pair9. The
CAN bus incorporates two terminating resistors.
One terminator is built into the Engine Control
Module (ECM) and the other is built into the Sentry
Key Remote Entry Module (SKREEM). Each resis-
tor has a value of 120 ohms. The resistor condition
can be confirmed by disconnecting the control mod-
ule and measuring the resistance value at the
appropriate control module pins. This measure-
ment should read 120 ohms. The two CAN circuits,
CAN C Bus (+) and CAN C Bus (-), are bridged by
these two terminating resistors when all control
modules are connected to the bus. These two resis-
tors are connected to the CAN bus network in
parallel. The measurement between the two
twisted CAN circuits, with both the ECM and
SKREEM connected, should measure a value of 60
ohms.
The CAN bus is bi-directional. This means that
each connected control module can send and receive
information. Transmission of data takes place re-
dundantly via both circuits. The data bus levels are
mirrored, meaning that if the binary level on one
circuit is 0, the other circuit transmits binary level
1 and vice versa. The two line concept is used for
two reasons: for fault identification and as a safety
concept.
If a voltage peak occurs on just one circuit, the
receivers can identify this as a fault and ignore the
voltage peak. If a short circuit or interruption
occurs on one of the two CAN circuits, a software-
hardware linked safety concept allows switching to
a single-line operation. The defective CAN circuit is
shut down. A specific data protocol controls how and
when the participants can send and receive.
NOTE: It is important to note the CAN Bus
circuits are used for inter-module
communication only, and is no way
connected to the K-Lines.
The following modules that use the CAN Bus on
this vehicle are:
²Automatic Temperature Control (ATC)
²Controller Antilock Brake (CAB)
²Engine Control Module (ECM)
²Instrument Cluster (IC)
²Sentry Key Remote Entry Module (SKREEM)
²Shifter Assembly (SA)
²Transmission Control Module (TCM)
3.3 HEATING & A/C SYSTEM
3.3.1 AUTOMATIC TEMPERATURE
CONTROL (ATC)
3.3.1.1 SYSTEM CONTROLS
The ATC Module:
²is fully addressable with the DRBIIIt.
IThe DRBIIItcommunicates with the ATC
Module through the Diagnostic Link Connector
(DLC) via a K-Line.
²communicates with other modules over the Con-
troller Area Network (CAN) C Bus.
²controls A/C clutch operation.
²controls EBL operation.
²controls water cycle valve operation.
IThe water cycle valve is a normally open valve,
meaning that it allows full engine coolant flow
through the heater core when no power is
delivered to the valve. The ATC controls the
valve with a pulse width signal. The lower the
percentage of the pulse width signal the more
the valve is open.
²controls Residual Heat Utilization (REST) func-
tion.
²controls blower motor operation, providing four
blower speeds (Low, M1, M2, & High).
²controls recirculation air solenoid valve.
²controls the mode door via cables.
²controls the main power supply to the Heater
Booster (if equipped).
²uses air inlet temperature sensor, air outlet tem-
perature sensor, and evaporator temperature
sensor input, as well as data from other modules
to maintain occupant comfort levels.
3.3.1.2 SYSTEM DIAGNOSTICS
Fault detection is through active and stored Diag-
nostic Trouble Codes (DTCs)
²DTCs are displayed by the DRBIIIt.
²Active DTCs are those which currently exist in
the system. The condition causing the fault must
be repaired in order to clear this type of DTC.
²Stored DTCs are those which occurred in the
system since the ATC Module received the last
9clear diagnostic info9message.
Testing Preparation & Diagnostics
Set the necessary system functions accordingly so
that all of the following prerequisites are met prior
to performing diagnostic tests on the ATC system:
5
GENERAL INFORMATION

1. Connect the DRBIIItto the DLC.
2. Place the shift lever in park.
3. Start the engine.
4. Set the blower to high speed.
5. Set the temperature selector to full cold.
6. Press air conditioning switch on.
7. With the DRBIIItin Sensors, verify that the:
A. ambient temperature is above 59F (15C).
B. refrigerant pressure is between 29 and 348
PSI (2 and 24 bar).
C. evaporator temperature is above 36.5F
(2.5C).
D. coolant temperature is above 158F (70C).
When all of the prerequisites have been met, use
the DRBIIItto record and erase all stored ATC
DTCs, and then select System Tests, and run the
ATC Function Test. When complete, check to see if
any active DTCs are present. If so, refer to the
symptom list in the Heating & A/C category for the
diagnostic procedure(s). If there are no DTCs
present, yet the performance seems less than ideal,
use the DRBIIItto look at all sensor values and the
status of the various inputs and outputs to see if
there is a deficiency detected that has not fully shut
down the system. For additional information, refer
to Sensor Values and Input/Output Status under
Diagnostic Tips in this section and to Section 11.0
for evaporator temperature sensor and air outlet
temperature sensor resistance to temperature spec-
ifications charts. Also, confirm that the water cycle
valve is functioning. Remember that the valve is
normally open. The pulse width signal will offer
insight into the valve's operation. The lower the
percentage number, the more open the valve be-
comes. Confirm that the valve is responding to the
signal from the ATC. If functioning correctly, verify
mode and blend door operation. If okay, the diagno-
sis then becomes purely refrigerant system related.
Attach the appropriate gauges and diagnose the
refrigeration system. Refer to the Service Informa-
tion for refrigerant system diagnostic procedures.
DIAGNOSTIC TIPS
SENSOR VALUES
Ambient Air Temperature
The Instrument Cluster transmits Ambient Air
Temperature Sensor data. In the event of a CAN
Bus communication failure, the last stored value is
displayed as a substitute value.
Interior Temperature
The normal range for the Interior Temperature
Sensor is from 32ÉF to 104ÉF. An implausible tem-
perature value indicates that the Interior Temper-
ature Sensor is bad. The repair in this case would be
to replace the ATC Module since the sensor is
integral to the module.Evaporator Temperature
The normal range for the Evaporator Temperature
Sensor is from 14ÉF to 104ÉF. A substitute value of
14ÉF with no updates indicates an Evaporator Tem-
perature Sensor circuit failure.
Air Outlet Temperature
The normal range for the Air Outlet Temperature
Sensor is from 32ÉF to 203ÉF. A substitute value of
111.1ÉF indicates an Air Outlet Temperature Sensor
circuit failure.
Coolant Temperature
The Engine Control Module transmits Coolant
Temperature Sensor date. In the event of a CAN
Bus communication failure, 257ÉF is displayed as a
substitute value.
Interior Temperature Controller
The normal range for the Blend control is from 62ÉF
to 144ÉF. This value represents the temperature set
by the operator. An implausible temperature value
or a temperature value that fails to change when
rotating the Blend control indicates that the Blend
control is bad. The repair in this case would be to
replace the ATC Module since the Blend control
integral to the module.
Refrigerant Pressure
The normal range for the Refrigerant Pressure
Sensor is from 29 PSI to 406 PSI. A substitute value
of 413 PSI indicates a Refrigerant Pressure Sensor
circuit failure. In addition, the normal range for
Pressure Sensor voltage is 0 volts to 5 volts. A value
of 0.9 volts indicates an open voltage supply circuit,
while a value of -999 indicates an open in all three
sensor circuits.
Water Cycle Valve
The normal range of the Water Cycle Valve is from
0% to 100%. The value indicates the extent to which
the valve is closed. A value of 100% indicates that
the valve is fully closed.
Intense Inst Light
The Instrument Cluster transmits this data. The
normal range for lighting intensity is from 0% to
100%. The value indicates the extent to which the
illumination has dimmed. A value of 0% indicates
bright while a value >0% indicates dimming. In the
event of a CAN Bus communication failure, 0% is
displayed as a substitute value.
INPUT/OUTPUT STATUS
Compressor Clutch
The ATC Module transmits this data. A status of
9ON9indicates that the compressor is operational. A
status of9OFF9indicates the compressor is not
operational.
6
GENERAL INFORMATION

Compres SO Accel (Compressor Shut Off - Due
To Acceleration)
The Engine Control Module transmits this data. A
status of9YES9indicates that the compressor shut
off because of an acceleration request. A status of
9NO9indicates that there is no acceleration request.
If shut off due to an acceleration request, the
compress will switch on again after 20 seconds. In
addition, the original acceleration request can no
longer exist for the ECM to acknowledge a subse-
quent request. In the event of a CAN Bus commu-
nication failure,9NO9is displayed as a substitute
value.
Compres SO W/E-Off (Compressor Shut Off -
Due to Emergency Off)
The Engine Control Module transmits this data. A
status of9YES9indicates that the compressor shut
off because of an emergency off request. A status of
9NO9indicates that there is no emergency off re-
quest. In the event of a CAN Bus communication
failure, the last stored value is displayed as a
substitute value.
Auxiliary Fan
The ATC Module transmits this data. A status of
9ON9indicates that the auxiliary fan is operational.
A status of9OFF9indicates that the auxiliary fan is
not operational. The Auxiliary Fan normally oper-
ates when refrigerant head pressure exceeds 290
PSI and coolant temperature exceeds 221ÉF. In the
event of a CAN Bus communication failure, 257ÉF is
displayed for coolant temperature (in Sensors) and
the Auxiliary Fan will run continuously.
Light PB CTRL Module
This input displays a status of9Bright9for positive
dimmer switch operation and9Dimmed9for nega-
tive dimmer switch operation. In the event of a CAN
Bus communication failure,9Bright9is displayed.
3.3.2 CABIN HEATER MODULE (CHM) &
HEATER BOOSTER MODULE (HBM)
3.3.2.1 SYSTEM DESCRIPTION
WARNING: NEVER OPERATE THE HEATER
IN AN ENCLOSED AREA THAT DOES NOT
HAVE EXHAUST VENTILATION FACILITIES.
ALWAYS VENT THE HEATER'S EXHAUST
WHEN OPERATING THE HEATER. REFER TO
(VENTING THE HEATER'S EXHAUST(
BELOW FOR PROPER EXHAUST VENTING
INSTRUCTIONS. FAILURE TO FOLLOW
THESE INSTRUCTIONS CAN RESULT IN
PERSONAL INJURY OR DEATH.
WARNING: ALLOW THE HEATER ASSEMBLY TO
COOL BEFORE PERFORMING A COMPONENT
INSPECTION/REPAIR/REPLACEMENT. FAILURE
TO FOLLOW THESE INSTRUCTIONS CAN
RESULT IN PERSONAL INJURY OR DEATH.
WARNING: ALWAYS DISCONNECT THE
VEHICLE'S BATTERY PRIOR TO
PERFORMING ANY TYPE OF WORK ON THE
HEATER ASSEMBLY. FAILURE TO FOLLOW
THESE INSTRUCTIONS CAN RESULT IN
PERSONAL INJURY OR DEATH.
WARNING: NEVER ATTEMPT TO REPAIR THE
HEATER ASSEMBLY OR ANY OF ITS
INTERNAL COMPONENTS. ALWAYS
PERFORM HEATER COMPONENT
REPLACEMENT IN ACCORDANCE WITH THE
SERVICE INFORMATION. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN
RESULT IN PERSONAL INJURY OR DEATH.
CAUTION: Always Perform The Heater
Pre-Test (In The Diagnostic Procedures) Prior
To Performing Any Other Test On The Heater
For The Test Result To Be Valid.
NOTE: Do not disconnect the vehicle's
battery or the heater's main power-supply
while the heater is in operation or in
run-down mode. Failure to follow these
instructions may result in excess emissions
from the heater.
NOTE: Failure to prime the Dosing Pump
after draining the fuel line will prevent heater
activation during the first attempt to start the
unit. This may also set a Diagnostic Trouble
Code (DTC) in the control unit's memory. Do
not perform the Dosing Pump Priming
Procedure if an attempt was made to start the
heater without priming the Dosing Pump
first. This will put excess fuel in the heater
module and cause smoke to emit from the
heater's exhaust pipe when heater activation
occurs.
NOTE: Waxed fuel can obstruct the fuel line
and reduce flow. Check for the appropriate
winter grade fuel and replace as necessary.
The Cabin Heater Assembly and Heater Booster
Assembly are supplemental type heaters designed
to pre-heat the engine's coolant in order to supply
the vehicle's occupants with heat prior to the engine
7
GENERAL INFORMATION