immobilizer MERCEDES-BENZ SPRINTER 2006 Service Manual

Static Heater Signal
A status of9ON9indicates that the heater module
sees the9Stationary Heating Mode ON9signal after
switching on the heater with the heater timer or the
auxiliary heater switch. A status of9OFF9indicates
that the9Stationary Heating Mode ON9signal is
not present at the heater module.
Heater Booster Mode Signal
A status of9ON9indicates that the heater module
sees the9Heater Booster Mode ON9signal after
switching on the heater with the auxiliary heater
switch. A status of9OFF9indicates that the9Heater
Booster Mode ON9signal is not present at the
heater module.
3.4 INSTRUMENT CLUSTER
The Instrument Cluster has easy-to-read instru-
ments, is capable of CAN bus communication and
provides a diagnostic function. The Instrument
Cluster with analog speedometer, tachometer, fuel
and coolant temperature gauges comes in two ver-
sions.
²Speedometer with outer miles-per-hour (mph)
scale and inner kilometers-per-hour (km/h) scale.
Coolant temperature is indicated in Fahrenheit
(for US).
²Speedometer with outer kilometers-per-hour
(km/h) scale and inner miles-per-hours (mph)
scale. Coolant temperature is indicated in de-
grees Celsius (for Canada).
Below the speedometer, there is a LCD multi-
function indicator in clear view of the driver. Warn-
ing and indicator lights (based on colored light
emitting diodes) are located in the bottom of the
instrument cluster with the exception of the turn
signal indicator lights, ASR warning light and re-
serve fuel warning light. The warning lights for the
seat belt usage and parking brake/brake fluid level
are located in the line above the bottom line. The
indicator that illuminates up when the parking
brake is applied or the brake fluid level is low is
different for U.S. and Canada.
When the key is turned to the 2nd position in the
ignition, the function of the following indicator
lights is checked automatically: High Beam ON,
Preheating, airbag malfunction. In case of a broken
LED of the airbag malfunction light, the seat belt
usage warning light will flash for 6 seconds after
the function check is finished. The Instrument
Cluster is operated with the help of 4 buttons
located below the multifunction indicator. The back-
lighting for the instrument cluster uses yellow
LED's and can be adjusted electronically to daylight
and darkness.The instrument cluster includes a warning
buzzer, which sounds (in addition to a warning light
in some cases) when:
²The headlights are on with the ignition off and
the door opened.
²The driver 's seat belt is not fastened with the
ignition on.
²The key is in the ignition and the door is open.
²Critical ASSYST information is displayed in the
multifunction indicator.
3.5 POWER DOOR LOCKS/RKE
3.5.1 CENTRAL LOCKING
The Central Locking System locks all vehicle
doors if any door is locked from the inside or
mechanically locked with the key from the outside.
However, unlocking any door, in that manner, will
only unlock that particular door. The Master Door
Lock Switch on the dash enables the operator to
lock/unlock all doors. By pressing the top of the
rocker type switch once, all doors will lock. Pressing
the switch again will unlock all doors. Pressing the
lower part of the switch once will lock all doors
except the driver door. Pressing the lower part
again will unlock all doors except the driver door. If
the Central Locking System automatically unlocks
after the vehicle was attempted to be locked, at
least one door is not properly closed.
There are two LED indicators in the Master Door
Lock Switch. The left indicator is for the driver door
and the right indicator is for all passenger/cargo
doors. These will indicate if a door is ajar or if the
doors are locked. The door ajar switches are part of
the door lock motor and are mounted in the door
latch assembly.
Inside each door lock motor there is a command
switch. The command switch is operated by the
plunger and signals any change in the lock status,
locked or unlocked. Each command switch is wired
to the Central Timer Module (CTM) sometimes
referred to as the Central Locking Module. If all
doors are closed and are unlocked, and any door is
locked by the key or the interior handle, thereby
changing the command switch, all doors will be
locked. If one of the door lock motors does not reach
the end position after a locking command, it will be
detected by the CTM (command switch not in
9Locked9position) and the vehicle will be unlocked.
3.5.2 REMOTE KEYLESS ENTRY (RKE)
The SKREEM is a combination of the Remote
Keyless Entry Module and the SKIM (Sentry Key
Immobilizer Module). It is located behind the In-
strument Cluster and has an antenna that goes up
9
GENERAL INFORMATION

the A-pillar. The SKREEM receives radio messages
from the RKE transmitter (fob) and sends com-
mands via the RKE Interface circuit to the CTM. If
the vehicle is equipped with VTSS, the Security
System Module will be connected in series between
the SKREEM and the CTM.
Confirmation of the RKE Lock/Unlock state is
accomplished via the turn signals. When the vehicle
is locked via RKE the turn signals will flash three
times. When it is unlocked via RKE, the turn
signals will flash one time. If the vehicle has been
unlocked via RKE and no door is opened within 40
seconds, the entire vehicle will be locked again
automatically.
If a transmitter (fob) is operated more than 255
times in succession beyond the range of the receiver
(SKREEM), the RKE portion of the key will become
inoperative. In order to put it back in synchroniza-
tion it will be necessary to have ALL the other
transmitters that are used with this vehicle avail-
able and follow the following procedure:
1. Cycle the ignition on and off 2 times within 6
seconds (leave in off position).
2. Press the lock or unlock button of the disabled
transmitter within 3 seconds of turning the
ignition off.
3. Press any button (lock or unlock) 3 more times
within 6 seconds.
4. Wait 10 seconds.
5. Press any button of ALL other transmitters
belonging to this vehicle at least once within
the next 20 seconds.
For problems related to the Immobilizer function
of the SKREEM, see Service Information.
3.5.3 AUTO DOOR LOCKS
Whenever the engine is started, the CTM receives
a message to lock all doors except the drivers door.
This is accomplished through the D+ Relay. The D+
Relay is controlled by the Instrument Cluster which
receives a command from the ECM that the engine
is running. This relay supplies power to the CTM
(for auto locking), the daytime running lamps and
the rear window defogger.
3.5.4 ACCIDENT RESPONSE
The CTM is hardwired to the Airbag Control
Module through the Enhanced Accident Report
Driver circuit. Anytime the vehicle airbags are
deployed, the CTM will unlock all doors and a
9Crash9DTC will be stored in memory. The door
locks will be inoperative until that code is cleared. If
the vehicle is severly jarred, but not enough to
deploy the airbags, it is possible that the DTC could
be set and therefore the door locks would be inop-
erable. Whenever the door locks are not opera-tional, use the DRBIII and check DTC's . If the code
9ACM has unlocked the doors9appears, use the
DRBIII and erase it.
3.6 VEHICLE THEFT SECURITY SYSTEM
(VTSS)
The Security System Module (SSM) is located
under the driver's seat. The SSM communicates
with the DRBIII over the K-line. If equipped the
Vehicle Theft Security System will monitor the
following:
²door jamb switches
²hood ajar switch
²ignition switch
²interior of the vehicle for movement
²longitudinal and transverse movement of the
vehicle
²rear defogger grids for glass breakage
²trailer connector
To arm the system the hood and all of the doors
must be closed when the vehicle is locked with the
RKE transmitter or with the use of the key in the
driver door. If the key is used, it must be held in the
lock position for 2 seconds. When the system is first
activated, the hazard lamps will flash 3 times. Also
with the system armed, the Towing/Intrusion Sen-
sor On/Off Switch indicator will flash to indicate an
armed system. To disarm the system use the RKE
or the driver door lock cylinder. Unlocking and
opening one of the other doors with the system
armed will trip the vehicle theft security system.
Interior monitoring is done by the use of an
Intrusion Sensor located in the front headliner and
with one or two sensors in the ceiling of the cargo
area depending on how the vehicle is equipped.
Monitoring of the interior of the vehicle will begin
after the system has been armed for 30 seconds. The
on/off switch located on the instrument panel can be
used to turn off this feature with the ignition switch
in either the Locked/Off or ACC position. The vehi-
cle tow-monitoring feature can also be switched off
using this switch. Re-locking the vehicle a second
time will reactivate these features.
If a trailer is connected to the vehicle when the
system is armed, the SSM will sense a resistance
change on the turn signal circuits if the trailer
harness becomes disconnected and will trip the
alarm.
Tripping the vehicle theft security system will
cause the hazard lamps to flash and the siren to
sound at 30-second intervals. The siren is equipped
with it's own self-contained battery. In the event the
vehicle's battery power is disconnected the siren
will continue to sound on it's own.
10
GENERAL INFORMATION

TABLE OF CONTENTS - Continued
P1480-GLOW PLUG INDICATOR ERROR...................................79
P1482-GLOW PLUG MODULE - COMMUNICATION ERROR....................80
P2537-GLOW PLUG CONTROL CIRCUIT PREGLOW FAULT...................80
P2537-GLOW PLUG CONTROL CIRCUIT PREGLOW SHORT TO GROUND.......80
P2537-GLOW PLUG CONTROL CIRCUIT PREGLOW SHORT TO VOLTAGE......80
P1482-GLOW PLUG MODULE - EXCESS CURRENT..........................82
P2133-GLOW PLUG #1 CIRCUIT EXCESSIVE CURRENT......................82
P2133-GLOW PLUG #1 CIRCUIT OPEN CIRCUIT............................82
P2133-GLOW PLUG #1 CIRCUIT SHORT TO GROUND.......................82
P2133-GLOW PLUG #1 CIRCUIT SHORT TO VOLTAGE.......................82
P2134-GLOW PLUG #2 CIRCUIT EXCESSIVE CURRENT......................82
P2134-GLOW PLUG #2 CIRCUIT OPEN CIRCUIT............................82
P2134-GLOW PLUG #2 CIRCUIT SHORT TO GROUND.......................82
P2134-GLOW PLUG #2 CIRCUIT SHORT TO VOLTAGE.......................82
P2135-GLOW PLUG #3 CIRCUIT EXCESSIVE CURRENT......................82
P2135-GLOW PLUG #3 CIRCUIT OPEN CIRCUIT............................82
P2135-GLOW PLUG #3 CIRCUIT SHORT TO GROUND.......................82
P2135-GLOW PLUG #3 CIRCUIT SHORT TO VOLTAGE.......................82
P2136-GLOW PLUG #4 CIRCUIT EXCESSIVE CURRENT......................82
P2136-GLOW PLUG #4 CIRCUIT OPEN CIRCUIT............................82
P2136-GLOW PLUG #4 CIRCUIT SHORT TO GROUND.......................82
P2136-GLOW PLUG #4 CIRCUIT SHORT TO VOLTAGE.......................82
P2137-GLOW PLUG #5 CIRCUIT EXCESSIVE CURRENT......................82
P2137-GLOW PLUG #5 CIRCUIT OPEN CIRCUIT............................82
P2137-GLOW PLUG #5 CIRCUIT SHORT TO GROUND.......................82
P2137-GLOW PLUG #5 CIRCUIT SHORT TO VOLTAGE.......................82
P1482-GLOW PLUG MODULE - INCORRECT TIMER.........................85
P1482-GLOW PLUG MODULE - INTERNAL FAULT...........................85
P2538-GLOW PLUG MODULE COMMUNICATION ERROR.....................85
P2538-GLOW PLUG MODULE EXCESSIVE CURRENT ERROR.................85
P2538-GLOW PLUG MODULE TIMER ERROR...............................85
P1610-ENGINE CONTROL RELAY PLAUSIBILITY............................87
P1610-ENGINE CONTROL RELAY SHUTS OFF TOO EARLY...................89
P1610-ENGINE CONTROL RELAY SHUTS OFF TOO LATE....................91
P1611-SENSOR SUPPLY 1 VOLTAGE IS TOO HIGH..........................94
P1611-SENSOR SUPPLY 1 VOLTAGE IS TOO LOW..........................96
P1612-IGNITION VOLTAGE - VOLTAGE ERROR.............................99
P1615-ECM VOLTAGE SUPPLY IS TOO HIGH..............................100
P1615-ECM VOLTAGE SUPPLY IS TOO LOW...............................100
P1630-IMMOBILIZER...................................................102
P1630-IMMOBILIZER...................................................102
P1630-IMMOBILIZER...................................................102
P1630-IMMOBILIZER...................................................102
P2201-IMMOBILIZER CAN MESSAGE ERROR..............................102
P2243-NO MESSAGE RECEIVED FROM SKREEM..........................102
P1681-ACM CIRCUIT FAULT.............................................104
P1681-ACM CIRCUIT SHORT TO VOLTAGE................................104
P2009-WATER IN FUEL SENSOR - WATER IN FUEL.........................106
P2009-WATER IN FUEL SENSOR SIGNAL ERROR..........................106
P2010-MASS AIR FLOW SENSOR NEGATIVE DEVIATION....................110
P2010-MASS AIR FLOW SENSOR POSITIVE DEVIATION.....................110
P2068-MASS AIR FLOW SENSOR PLAUSIBILITY SIGNAL RATIO TOO LARGE . . .110
P2068-MASS AIR FLOW SENSOR PLAUSIBILITY SIGNAL RATIO TOO SMALL . . .110
v

1.0 INTRODUCTION
The procedures contained in this manual include
all specifications, instructions and graphics needed
to diagnose engine control module (ECM) and sen-
try key remote entry module (SKREEM) problems;
they are no start, diagnostic trouble code (DTC) and
no trouble code problems for the ECM. The diagnos-
tics in this manual are based on the trouble condi-
tion or symptom being present at the time of diag-
nosis.
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. IT IS RECOMMENDED
THAT YOU REVIEW THE ENTIRE MANUAL TO
BECOME FAMILIAR WITH ALL NEW AND
CHANGED DIAGNOSTIC PROCEDURES.
This manual will cover all the necessary require-
ments to begin a logical diagnostic path for each
problem. If there is a diagnostic trouble code (DTC)
detected, go to the trouble code test. If there are no
DTCs present, go to a no trouble code (*), symptom
based test.
This book reflects many suggested changes from
readers of past issues. After using this book, if you
have any comments or recommendations, please fill
out the form at the back of the book and mail it back
to us.
1.1 SYSTEM COVERAGE
This diagnostic procedures manual covers 2005
Sprinter vehicles equipped with the 2.7L common
rail diesel engine.
1.2 SIX-STEP TROUBLESHOOTING
PROCEDURE
Diagnosis of the engine control module (ECM)
and sentry key immobilizer system (SKREEM) is
done in six basic steps:
²verification of complaint
²verification of any related symptom
²symptom analysis
²problem isolation
²repair of isolated problem
²verification of proper operation
NOTE: All tests in this manual should be per-
formed with the engine at operating temperature,
unless otherwise specified within a particular test.
2.0 IDENTIFICATION OF
SYSTEM
The ECM is located to the left of the steering
column behind the steering column opening cover.
The sentry remote entry module (SKREEM) is
attached to the rear of the instrument cluster.
3.0 SYSTEM DESCRIPTION AND
FUNCTIONAL OPERATION
3.1 GENERAL DESCRIPTION
The 2.7L direct injection diesel engine system is
equipped with the latest technical advances. The
on-board diagnostics incorporated in the engine
control module and SKREEM are intended to assist
the field technician in repairing vehicle problems by
the quickest means.
The engine system incorporates a common rail
fuel delivery design with exhaust emission feed-
back. This design utilizes electronically controlled
solenoid valve type fuel injectors. Each injector is
controlled individually by the ECM. Injector timing
and fuel quantity are controlled by the ECM based
on inputs from various sensors. The precision con-
trol of the injectors by the ECM helps to reduce the
engine noise, odor and smoke.
3.2 FUNCTIONAL OPERATION
3.2.1 ECM ON-BOARD DIAGNOSTICS
The ECM is programmed to monitor different
circuits of the diesel fuel injection system. This
monitoring is called on-board diagnostics.
Certain criteria must be met for a diagnostic
trouble code to be entered into the ECM memory.
The criteria may be a range of: engine rpm, engine
temperature, time or other input signals to the
ECM. If all of the criteria for monitoring a system or
circuit are met, and a problem is sensed, then a
DTC will be stored in the ECM memory.
It is possible that a DTC for a monitored circuit
may not be entered into the ECM memory, even
though a malfunction has occurred. This may hap-
pen when the monitoring criteria have not been
met.
The ECM compares input signal voltages from
each input device with specifications (the estab-
lished high and low limits of the input range) that
are programmed into it for that device. If the input
voltage is not within the specifications and other
trouble code criteria are met, a DTC will be stored
in the ECM memory.
1
GENERAL INFORMATION

fuel rail pressure malfunction rail pressure too high
fuel rail pressure malfunction rail pressure too low
fuel temperature sensor circuit signal voltage too
high
fuel temperature sensor circuit signal voltage too
low
fuel temperature sensor plausibility
general leakage
glow plug #1 circuit excessive current
glow plug #1 circuit open circuit
glow plug #1 circuit short to ground
glow plug #1 circuit short to voltage
glow plug #2 circuit excessive current
glow plug #2 circuit open circuit
glow plug #2 circuit short to ground
glow plug #2 circuit short to voltage
glow plug #3 circuit excessive current
glow plug #3 circuit open circuit
glow plug #3 circuit short to ground
glow plug #3 circuit short to voltage
glow plug #4 circuit excessive current
glow plug #4 circuit open circuit
glow plug #4 circuit short to ground
glow plug #4 circuit short to voltage
glow plug #5 circuit excessive current
glow plug #5 circuit open circuit
glow plug #5 circuit short to ground
glow plug #5 circuit short to voltage
glow plug control circuit preglow fault
glow plug control circuit preglow short to ground
glow plug control circuit preglow short to voltage
glow plug control module circuit open circuit
glow plug control module circuit shorted to ground
glow plug control module circuit shorted to voltage
or open
glow plug control module fault
glow plug indicator error
glow plug module communication error
glow plug module -communication error
glow plug module -excess current
glow plug module excessive current error
glow plug module -incorrect timer
glow plug module -internal fault
glow plug module timer error
ignition voltage -voltage error
immobilizer
immobilizer
immobilizer
immobilizer
immobilizer can message error
improper start attempt
injection fault excessive engine speed
injection fault -excessive temperature
injection fault -quantity error
injection fault -torque limit
injector 1 injection time above limit
injector 1 injection time below limit
injector 2 injection time above limitinjector 2 injection time below limit
injector 3 injection time above limit
injector 3 injection time below limit
injector 4 injection time above limit
injector 4 injection time below limit
injector 5 injection time above limit
injector 5 injection time below limit
injector bank error
injector bank error
injector circuit fault
injector circuit fault
injector circuit low side shorted to ground
injector circuit low side shorted to ground
injector circuit shorted to ground or voltage
injector circuit shorted to ground or voltage
instrument cluster message -ambient temperature
signal plausibility
instrument cluster message plausibility
intake air temp sensor circuit signal voltage too high
intake air temp sensor circuit signal voltage too low
intake air temp sensor signal voltage too high
intake air temp sensor signal voltage too low
intake pressure sensor can message error
intake pressure sensor circuit fault
intake pressure sensor intake restriction
intake pressure sensor open circuit
intake pressure sensor plausibility
intake pressure sensor plausibility
intake pressure sensor signal voltage too high
intake pressure sensor signal voltage too high
intake pressure sensor signal voltage too high
intake pressure sensor signal voltage too low
intake pressure sensor signal voltage too low
intake pressure sensor signal voltage too low
internal error counter fault
internal error engine shut off
internal error engine voltage monitoring
internal error engine voltage monitoring
internal voltage error
kickdown switch plausibility
lateral accelerator sensor plausibilty
leakage cylinder #1
leakage cylinder #2
leakage cylinder #3
leakage cylinder #4
leakage cylinder #5
maf sensor signal plausibility
manual transmissio coded as auto transmission
mass air flow sensor negative deviation
mass air flow sensor plausibility
mass air flow sensor plausibility air mass too high
mass air flow sensor plausibility air mass too high
mass air flow sensor plausibility air mass too low
mass air flow sensor plausibility air mass too low
mass air flow sensor plausibility signal ratio error
mass air flow sensor plausibility signal ratio too
large
mass air flow sensor plausibility signal ratio too
6
GENERAL INFORMATION

Symptom List:
P1630-IMMOBILIZER
P1630-IMMOBILIZER
P1630-IMMOBILIZER
P1630-IMMOBILIZER
P2201-IMMOBILIZER CAN MESSAGE ERROR
P2243-NO MESSAGE RECEIVED FROM SKREEM
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P1630-IMMOBILIZER.
POSSIBLE CAUSES
CHECKING SKREEM DTC'S
OPEN CAN BUS CIRCUITS
SKREEM MODULE
INTERMITTENT CONDITION
TEST ACTION APPLICABILITY
1NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Turn the ignition off for 10 seconds.
Turn the ignition on.
Monitor the DRB for ECM DTCs.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 4
2 Turn the ignition on.
With the DRBIIIt, attempt to communicate with the SKREEM and read SKREEM
DTCs.
NOTE: If the DRB is unable to communicate with the SKREEM, refer to the
appropriate test in the Communication category
Are there any SKREEM DTC's?All
Ye s!Repair SKREEM DTC's as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 3
102
DRIVEABILITY - DIESEL

TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the SKREEM Module harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of each CAN Bus circuit between the ECM harness connector
and the SKREEM harness connector.
Is the resistance below 10.0 ohms for each measurement?All
Ye s!Replace and program the SKREEM Module in accordance with
the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Repair the open CAN Bus circuit(s) between the ECM and the
SKREEM.
Perform ROAD TEST VERIFICATION - VER-2.
4WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DTC When Monitored and Set Conditions. If possible, try to duplicate the
conditions under which the DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s!Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Test Complete.
103
DRIVEABILITY - DIESEL
P1630-IMMOBILIZER ÐContinued

NO START VERIFICATION - VER-1 APPLICABILITY
1. NOTE: IMPORTANT! If the Engine Control Module or Sentry Key Immobilizer
Module has been replaced, ensure the programming procedure for the module has
been performed in accordance with the Service Information.
2. Inspect the vehicle to ensure that all engine components are properly installed and
connected. Reassemble and reconnect components as necessary.
3. Inspect the engine oil for contamination. If it is contaminated, change the oil and filter.
4. With the DRB, erase all diagnostic trouble codes (DTCs).
5. Turn the ignition off for at least 10 seconds.
6. Attempt to start the engine.
7. If the engine is unable to start, look for any Technical Service Bulletins (TSBs) that may
relate to this condition. Return to the Symptom List if necessary.
8. If the engine starts and continues to run, the repair is now complete.
Are any DTCs or symptoms remaining?All
Ye s!Repair is not complete, refer to appropriate symptom.
No!Repair is complete.
ROAD TEST VERIFICATION - VER-2 APPLICABILITY
1. Inspect the vehicle to ensure that all engine components are properly installed and
connected. Reassemble and reconnect components as necessary.
2. If this verification procedure is being performed after a non-DTC test, perform steps 3 and
4. If not, proceed to step 5.
3. Check to see if the initial symptom still exists. If there are no trouble codes and the symptom
no longer exists, the repair was successful and testing is now complete.
4. If the initial or another symptom exists, the repair is not complete. Check all pertinent
Technical Service Bulletins (TSBs) and return to the Symptom List if necessary.
5. For previously read DTCs that have not been dealt with, return to the Symptom List and
follow the diagnostic path for that DTC; otherwise, continue.
6. If the Engine Control Module (ECM) has not been changed, perform steps 7 and 8, otherwise,
continue with step 9.
7. With the DRB IIIt, erase all diagnostic trouble codes (DTCs), then disconnect the DRB IIIt.
8. Turn the ignition off for at least 10 seconds.
9. If equipped with a Transfer Case Position Switch, perform step 10, otherwise, continue with
step 11.
10. With the ignition switch on, place the Transfer Case Shift Lever in each gear position,
stopping for 15 seconds in each position.
11. Ensure no DTCs remain by performing steps 12 through 15.
12. Road test the vehicle. For some of the road test, go at least 64 km/h (40 MPH). If this test
is for an A/C Relay Control Circuit, drive the vehicle for at least 5 minutes with the A/C on.
13. At some point, stop the vehicle and turn the engine off for at least 10 seconds, then restart
the engine and continue.
14. Upon completion of the road test, turn the engine off and check for DTCs with the DRB IIIt.
15. If the repaired DTC has set again, the repair is not complete. Check for any pertinent
Technical Service Bulletins (TSBs) and return to the Symptom List. If there are no DTCs, the
repair was successful and is now complete.
Are any DTCs or symptoms remaining?All
Ye s!Repair is not complete, refer to appropriate symptom.
No!Repair is complete.
247
VERIFICATION TESTS
Verification Tests ÐContinued

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

INSTRUMENT CLUSTER
DESCRIPTION
The instrument cluster for this model is an Elec-
troMechanical Instrument Cluster (EMIC) that is
located above the steering column opening in the
instrument panel, directly in front of the driver (Fig.
1). The remainder of the EMIC, including the mounts
and the electrical connections, are concealed within
the instrument panel behind the cluster bezel and
beneath the instrument panel top cover for the clus-
ter. The instrument cluster includes analog gauges,
meters, indicators, and acoustic signal transmit-
ters.The EMIC module also incorporates a multi-func-
tion indicator that consists of a digital Liquid Crystal
Display (LCD) unit for displaying odometer/trip
odometer information, an electronic digital clock,
engine oil level information, automatic transmission
gear selector position (PRNDL), and certain diagnos-
tic information. The multi-function indicator also has
four push button switches, which provide the vehicle
operator with an interface to adjust certain inputs to
the instrument cluster and to select from multiple
display options. If the vehicle is equipped with the
appropriate options, the multi-function indicator also
provides an outside ambient temperature indicator
display and an Active Service SYStem (ASSYST)
engine oil maintenance indicator to display engine oil
level and maintenance reminders.
The EMIC gauges and indicators are visible
through a dedicated opening in the cluster bezel on
the instrument panel and are protected by a clear
plastic cluster lens (Fig. 2) that is secured by eight
integral latches to the molded black plastic cluster
hood. Four, black plastic multi-function indicator
switch push buttons protrude through dedicated
holes in a rectangular black plastic switch bezel that
is integral to the cluster lens and located near the
lower edge of the cluster directly below the multi-
function indicator LCD unit. The cluster hood serves
as a visor and shields the face of the cluster from
ambient light and reflections to reduce glare. The
cluster hood has eight integral latches that engage
eight integral latch tabs on the cluster rear cover,
sandwiching the cluster housing unit between the
hood and the rear cover. The cluster hood also has
two integral pivot loops molded into its underside
that engage two pairs of molded pivot hooks that are
integral to the top of the instrument panel base
structure. These pivots allow the cluster to be rolled
rearward to ease service access to the wire harness
connectors at the back of the cluster.
The rear of the cluster housing and the EMIC elec-
tronic circuitry are protected by the molded plastic
rear cover. A mounting ear at each upper corner of
the rear cover are used to secure the EMIC to the
molded plastic instrument panel base unit with two
screws. The rear cover includes clearance holes for
the two cluster connector receptacles on the cluster
electronic circuit board. The connector receptacles on
the back of the cluster electronic circuit board con-
nect the EMIC to the vehicle electrical system
through two take outs with connectors from the vehi-
cle wire harness. The EMIC rear cover includes a
molded mounting tab and a latch feature that
secures the Remote Keyless Entry (RKE)/immobilizer
module to the back of the cluster. The RKE/immobi-
lizer module is connected to the vehicle electrical sys-
tem through a separate take out and connector of the
vehicle wire harness.
Fig. 1 Instrument Cluster
1 - COVER
2 - BEZEL
3 - INSTRUMENT CLUSTER
4 - STEERING WHEEL
5 - MULTI-FUNCTION SWITCH
6 - SPEED CONTROL SWITCH
Fig. 2 Instrument Cluster Components
1 - LENS
2 - HOOD
3 - CLUSTER HOUSING
4 - REAR COVER
8J - 2 INSTRUMENT CLUSTERVA