2006 MERCEDES-BENZ SPRINTER sensor

TABLE OF CONTENTS - Continued
P2032-O2 SENSOR PLAUSIBILITY.......................................134
P2032-O2 SENSOR PLAUSIBILITY.......................................134
P2057-O2 SENSOR SIGNAL CIRCUIT SIGNAL VOLTAGE TOO HIGH...........134
P2058-O2 SENSOR SIGNAL CIRCUIT SIGNAL VOLTAGE TOO HIGH...........134
P2059-O2 SENSOR SIGNAL CIRCUIT SIGNAL VOLTAGE TOO HIGH...........134
P2090-O2 SENSOR PLAUSIBILITY.......................................134
P2090-O2 SENSOR SIGNAL FAULT.......................................134
P2091-O2 SENSOR LOW O2 CONCENTRATION............................134
P2091-O2 SENSOR SIGNAL PLAUSIBILITY................................134
P2195-O2 SENSOR HEATER CIRCUIT FAULT..............................134
P2353-O2 SENSOR PLAUSIBILITY.......................................134
P2366-O2 CIRCUIT FAULT..............................................134
P2034-O2 SENSOR CIRCUIT CALIBRATION VALUE TOO HIGH...............138
P2034-O2 SENSOR CIRCUIT CALIBRATION VALUE TOO LOW................138
P2036-O2 SENSOR CIRCUIT CALIBRATION VALUE TOO HIGH...............138
P2036-O2 SENSOR CIRCUIT CALIBRATION VALUE TOO LOW................138
P2038-O2 SENSOR CIRCUIT CALIBRATION VALUE TOO HIGH...............138
P2038-O2 SENSOR CIRCUIT CALIBRATION VALUE TOO LOW................138
P2043-CAMSHAFT POSITION SENSOR CIRCUIT OPEN CIRCUIT.............140
P2043-CAMSHAFT POSITION SENSOR CIRCUIT OPEN OR SHORT CIRCUIT . . .140
P2045-CRANKSHAFT POSITION SENSOR CIRCUIT LOST SIGNAL............146
P2045-CRANKSHAFT POSITION SENSOR CIRCUIT SIGNAL PLAUSIBILITY.....146
P2322-CRANKSHAFT POSITION SENSOR PLAUSIBILITY....................146
P2343-CKP PLAUSIBILITY...............................................146
P2062-ENGINE OIL SENSOR MONITORING ERROR........................149
P2066-MASS AIR FLOW SENSOR PLAUSIBILITY...........................150
P2355-EGR FLOW RATE IS TOO HIGH....................................150
P2355-EGR FLOW RATE IS TOO LOW....................................150
P2066-MASS AIR FLOW SENSOR PLAUSIBILITY AIR MASS TOO HIGH........153
P2066-MASS AIR FLOW SENSOR PLAUSIBILITY AIR MASS TOO LOW.........153
P2087-INTAKE PRESSURE SENSOR INTAKE RESTRICTION.................156
P2100-FUEL PUMP RELAY CIRCUIT OPEN CIRCUIT........................157
P2100-FUEL PUMP RELAY CIRCUIT SHORTED TO GROUND.................157
P2100-FUEL PUMP RELAY CIRCUIT SHORTED TO VOLTAGE................159
P2100-FUEL PUMP RELAY EXCESSIVE CURRENT..........................159
P2104-STARTER RELAY CIRCUIT SHORT CIRCUIT.........................161
P2152-STARTER RELAY CIRCUIT SHORT TO GROUND.....................161
P2153-STARTER RELAY CIRCUIT OPEN OR SHORTED TO VOLTAGE.........161
P2110-BOOST PRESSURE SERVO MOTOR CIRCUIT SHORT CIRCUIT.........164
P2112-BOOST PRESSURE SERVO MOTOR CIRCUIT EXCESSIVE CURRENT . . .164
P2526-BOOST PRESSURE SERVO MOTOR SHORT TO VOLTAGE.............164
P2111-BOOST PRESSURE SERVO MOTOR CIRCUIT SHORT TO GROUND.....167
P2112-BOOST PRESSURE SERVO MOTOR CIRCUIT OPEN CIRCUIT..........167
P2510-BOOST PRESSURE SERVO MOTOR SHORT TO GROUND.............167
P2526-BOOST PRESSURE SERVO MOTOR OPEN CIRCUIT..................167
P2526-BOOST PRESSURE SERVO MOTOR SHORT TO GROUND.............167
P2132-GLOW PLUG CONTROL MODULE CIRCUIT OPEN CIRCUIT............171
P2132-GLOW PLUG CONTROL MODULE CIRCUIT SHORTED TO GROUND. . . .171
P2132-GLOW PLUG CONTROL MODULE CIRCUIT SHORTED TO VOLTAGE OR
OPEN................................................................171
P2132-GLOW PLUG CONTROL MODULE FAULT............................171
P2151-FUEL PRESS SOLENOID SIGNAL PLAUSIBILITY HIGH................173
P2151-FUEL PRESS SOLENOID SIGNAL PLAUSIBILITY LOW.................173
vii

TABLE OF CONTENTS - Continued
P2500-FUEL PRESSURE SOLENOID CIRCUIT OPEN CIRCUIT................173
P2501-FUEL PRESSURE SOLENOID CIRCUIT SHORTED TO GROUND OR B+ . .173
P2197-FUEL QUANTITY SOLENOID OPEN CIRCUIT.........................177
P2198-FUEL QUANTITY SOLENOID SHORT TO VOLTAGE...................177
P2199-FUEL QUANTITY SOLENOID SHORT TO GROUND....................177
P2502-FUEL QUANTITY SOLENOID SHORT TO GROUND....................177
P2203-TORQUE REDUCTION MESSAGE FROM ABS - CAN PLAUSIBILITY.....180
P2203-TORQUE REDUCTION MESSAGE FROM ABS - MESSAGE ERROR......180
P2203-TORQUE REDUCTION MESSAGE FROM ABS - MESSAGES MISSING . . .180
P2203-TORQUE REDUCTION MESSAGE FROM ABS - NO COMMUNIOCATION .180
P2203-TORQUE REDUCTION MESSAGE FROM ABS - PLAUSIBILITY #1.......180
P2203-TORQUE REDUCTION MESSAGE FROM ABS PLAUSIBILITY #2.........180
P2208-ABS BRAKE SIGNAL CAN MESSAGE IMPLAUSIBLE..................180
P2208-ABS CAN BRAKE SIGNAL PLAUSIBILITY............................180
P2209-ABS CAN MESSAGE MISSING OR INCORRECT......................180
P2253-STEERING ANGLE SENSOR PLAUSIBILITY..........................180
P2204-TORQUE REDUCTION MESSAGE FROM TCM - CAN PLAUSIBILITY.....182
P2204-TORQUE REDUCTION MESSAGE FROM TCM - ENGINE STOP.........182
P2204-TORQUE REDUCTION MESSAGE FROM TCM - MESSAGE ERROR.....182
P2204-TORQUE REDUCTION MESSAGE FROM TCM - MESSAGES MISSING . . .182
P2204-TORQUE REDUCTION MESSAGE FROM TCM - PLAUSIBILITY..........182
P2204-TORQUE REDUCTION MESSAGE FROM TCM - TCM DTC #1...........182
P2204-TORQUE REDUCTION MESSAGE FROM TCM - TCM DTC #2...........182
P2210-ESM CAN MESSAGE MISSING OR INCORRECT......................184
P2234-ABS DTC EXTERNAL QUANTITY CONTROL FAULT PRESENT..........184
P2252-LATERAL ACCELERATOR SENSOR PLAUSIBILTY.....................184
P2211-ETC CAN MESSAGE MISSING OR INCORRECT......................186
P2258-TCM MESSAGE ERROR..........................................186
P2258-TCM NO CAN MESSAGE..........................................186
P2217-TCM DTC INTERNAL FAULT PRESENT..............................188
P2218-TCM DTC 1-2 AND 4-5 SHIFT SOLENOID FAULT PRESENT............188
P2219-TCM DTC 2-3 SHIFT SOLENOID FAULT PRESENT....................188
P2220-TCM DTC 3-4 SHIFT SOLENOID FAULT PRESENT....................188
P2221-TCM DTC TORQUE CONVERTER CLUTCH SOLENOID FAULT PRESENT .188
P2222-TCM DTC MODULATING PRESSURE SOLENOID FAULT PRESENT......188
P2223-TCM DTC SHIFT PRESSURE SOLENOID FAULT PRESENT.............188
P2224-TCM DTC VALVE VOLTAGE SUPPLY FAULT PRESENT................188
P2225-TCM DTC SPEED SENSOR VOLTAGE FAULT PRESENT...............188
P2226-TCM DTC EWM CAN MESSAGE FAULT PRESENT....................188
P2227-TCM DTC RIGHT REAR WHEEL SPEED IMPLAUSIBLE FAULT PRESENT .188
P2228-TCM DTC TRANSMISSION RATIO ERROR FAULT PRESENT...........188
P2229-TCM DTC CAN MSG IMPLAUSIBLE FAULT PRESENT.................188
P2230-TCM DTC TCC EXCESSIVE POWER CONSUMPTION FAULT PRESENT . .188
P2231-TCM DTC NOT UNEQUIVOCAL FAULT PRESENT.....................188
P2232-TCM DTC NEGATIVE GEAR COMPARISON FAULT PRESENT...........188
P2240-ABS STEERING ANGLE SENSOR CAN MESSAGE IMPLAUSIBLE 1......190
P2240-ABS STEERING ANGLE SENSOR CAN MESSAGE IMPLAUSIBLE 2......190
P2242-ABS BRAKE MESSAGE PLAUSIBILITY 1.............................192
P2242-ABS BRAKE MESSAGE PLAUSIBILITY 2.............................192
P2244-INSTRUMENT CLUSTER MESSAGE PLAUSIBILITY...................194
P2259-TORQUE REDUCTION MESSAGE FROM HVAC- PARITY ERROR........196
P2259-TORQUE REDUCTION MESSAGE FROM HVAC- SWITCH SIGNAL
ERROR..............................................................196
viii

TABLE OF CONTENTS - Continued
P2259-TORQUE REDUCTION MESSAGE FROM HVAC- SWITCH SIGNAL
PLAUSIBILITY.........................................................196
P229-INSTRUMENT CLUSTER MESSAGE - AMBIENT TEMPERATURE SIGNAL
PLAUSIBILITY.........................................................197
P2306-SENSOR SUPPLY 2 VOLTAGE IS TOO HIGH.........................198
P2306-SENSOR SUPPLY 2 VOLTAGE IS TOO LOW.........................200
P2332-SENSOR SUPPLY 3 VOLTAGE IS TOO LOW.........................203
P2332-SENSOR SUPPLY 3 VOLTAGE IS TOO HIGH.........................206
P2333-S/C VEHICLE SPEED PLAUSIBILITY................................209
P2338-S/C EXCESSIVE ACCELERATION..................................209
P2338-S/C EXCESSIVE DECELERATION..................................209
P2339-ECM CHECKSUM ERROR #1......................................211
P2339-ECM CHECKSUM ERROR #2......................................211
P2339-ECM INVALID CODING............................................211
P2339-ECM INVALID DATA..............................................211
P2344-KICKDOWN SWITCH PLAUSIBILITY................................212
P2347-AUTOMATIC TRANSMISSION CODED AS MANUAL TRANSMISSION.....213
P2347-CAN BUS CIRCUIT INTERUPTION..................................213
P2347-MANUAL TRANSMISSIO CODED AS AUTO TRANSMISSION............213
P2347-WRITE ERROR TO EEPROM......................................213
P2351-ECM SUPPLY VOLTAGE TOO LOW.................................214
P2359-BOOST PRESSURE TOO HIGH....................................216
P2359-BOOST PRESSURE TOO LOW.....................................216
P2511-EGR VALVE SIGNAL CIRCUIT SHORTED TO GROUND................218
P2527-EGR VALVE SIGNAL CIRCUIT OPEN CIRCUIT........................218
P2527-EGR VALVE SIGNAL CIRCUIT SHORTED TO GROUND................218
P2514-CRANKCASE VENT HEATER OPEN CIRCUIT........................221
P2514-CRANKCASE VENT HEATER SHORTED TO GROUND.................221
P2514-CRANKCASE VENT HEATER SHORTED TO VOLTAGE.................221
P2521-IMPROPER START ATTEMPT......................................224
P2527-EGR VALVE SIGNAL CIRCUIT SHORTED TO VOLTAGE................225
P2531-FUEL INJECTOR 1 READ TOO LARGE..............................227
P2531-FUEL INJECTOR 1 READ TOO LARGE..............................227
P2531-FUEL INJECTOR 1 READ TOO SMALL..............................227
P2531-FUEL INJECTOR 1 READ TOO SMALL..............................227
P2532-FUEL INJECTOR 2 READ TOO LARGE..............................227
P2532-FUEL INJECTOR 2 READ TOO LARGE..............................227
P2532-FUEL INJECTOR 2 READ TOO SMALL..............................227
P2532-FUEL INJECTOR 2 READ TOO SMALL..............................227
P2533-FUEL INJECTOR 3 READ TOO LARGE..............................227
P2533-FUEL INJECTOR 3 READ TOO LARGE..............................227
P2533-FUEL INJECTOR 3 READ TOO SMALL..............................227
P2533-FUEL INJECTOR 3 READ TOO SMALL..............................227
P2534-FUEL INJECTOR 4 READ TOO LARGE..............................227
P2534-FUEL INJECTOR 4 READ TOO LARGE..............................227
P2534-FUEL INJECTOR 4 READ TOO SMALL..............................227
P2534-FUEL INJECTOR 4 READ TOO SMALL..............................227
P2535-FUEL INJECTOR 5 READ TOO LARGE..............................227
P2535-FUEL INJECTOR 5 READ TOO LARGE..............................227
P2535-FUEL INJECTOR 5 READ TOO SMALL..............................227
P2535-FUEL INJECTOR 5 READ TOO SMALL..............................227
P2606-CMP/CKP SYNCHRONIZATION ERROR.............................229
*CHECKING THE FUEL PRESSURE SENSOR CIRCUITS.....................232
ix

TABLE OF CONTENTS - Continued
*CHECKING THE FUEL PRESSURE SOLENOID CIRCUITS...................233
*CHECKING THE FUEL QUANTITY SOLENOID CIRCUITS....................234
*CHECKING THE POWER AND GROUNDS................................235
*ENGINE CRANKS BUT WILL NOT START.................................239
*ENGINE WILL NOT CRANK.............................................242
VERIFICATION TESTS
VERIFICATION TESTS..................................................246
8.0 COMPONENT LOCATIONS..............................................249
8.1CONTROL MODULES.............................................249
8.2CONTROLS AND SOLENOIDS......................................249
8.3DATA LINK CONNECTOR..........................................250
8.4SENSORS.......................................................251
8.5SWITCHES......................................................253
9.0 CONNECTOR PINOUTS................................................255
ACCELERATOR PEDAL POSITION SENSOR (OBD).........................255
AIRBAG CONTROL MODULE - YELLOW...................................255
BOOST PRESSURE SENSOR (OBD)......................................255
BOOST PRESSURE SERVOMOTOR (OBD)................................256
CAMSHAFT POSITION SENSOR - BLACK.................................256
CONTROLLER ANTILOCK BRAKE........................................257
CRANKCASE HEATER - BLACK..........................................257
CRANKSHAFT POSITION SENSOR - BLACK...............................258
DATA LINK CONNECTOR - BLACK........................................258
EGR VALVE - BLACK...................................................258
ENGINE CONTROL MODULE C1 (OBD)...................................259
ENGINE CONTROL MODULE C2 (OBD)...................................260
ENGINE COOLANT TEMPERATURE SENSOR - BLACK......................260
ENGINE OIL SENSOR - BLACK..........................................261
FUEL INJECTOR NO. 1 - BLACK.........................................261
FUEL INJECTOR NO. 2 - BLACK.........................................261
FUEL INJECTOR NO. 3 - BLACK.........................................261
FUEL INJECTOR NO. 4 - BLACK.........................................262
FUEL INJECTOR NO. 5 - BLACK.........................................262
FUEL PRESSURE SENSOR - BLACK.....................................262
FUEL PRESSURE SOLENOID............................................262
FUEL PUMP (OBD).....................................................262
FUEL PUMP RELAY (OBD)..............................................263
FUEL QUANTITY CONTROL VALVE (OBD).................................263
FUEL TEMPERATURE SENSOR..........................................263
ENGINE CONTROL RELAY (FUSE BLOCK NO. 1)...........................265
FUSES (FUSE BLOCK NO. 1)............................................265
FUSES (FUSE BLOCK NO. 2)............................................267
FUSES (FUSE/RELAY BLOCK)...........................................269
STARTER MOTOR RELAY (FUSE/RELAY BLOCK)...........................269
GLOW PLUG CONTROL MODULE C1 - BLACK.............................270
GLOW PLUG CONTROL MODULE C2 - BLACK.............................270
INTAKE AIR PRESSURE SENSOR (OBD)..................................270
INTAKE AIR TEMPERATURE SENSOR - BLACK............................270
x

TABLE OF CONTENTS - Continued
KICK DOWN SWITCH - BLACK...........................................271
MASS AIR FLOW SENSOR - BLACK......................................271
OXYGEN SENSOR (OBD)...............................................271
FUSED IGNITION SWITCH RUN-START RELAY (RELAY BLOCK)..............273
SPEED CONTROL SWITCH.............................................273
WATER IN FUEL SENSOR - BLACK.......................................273
10.0 SCHEMATIC DIAGRAMS................................................275
10.1ENGINE CONTROL MODULE.......................................275
10.2ENGINE CONTROL MODULE.......................................276
11.0 CHARTS AND GRAPHS................................................277
xi

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

3.2.2 ECM OPERATING MODES
As input signals to the ECM change, the ECM
adjusts its response to the output devices. For
example, the ECM must calculate a different fuel
quantity and fuel timing for engine idle condition
than it would for a wide open throttle condition.
There are several different modes of operation that
determine how the ECM responds to the various
input signals.
Ignition Switch On (Engine Off)
When the ignition is turned on the ECM activates
the glow plug relay for a time period that is deter-
mined by engine coolant temperature, intake air
temperature and battery voltage.
Engine Start-Up Mode
The ECM uses the intake air temperature sensor,
engine temperature sensor and the crankshaft po-
sition sensor (engine speed) inputs to determine
fuel injection quantity.
Normal Driving Modes
Engine idle, warm-up, acceleration, deceleration
and wide open throttle modes are controlled based
on all of the sensor inputs to the ECM. The ECM
uses these sensor inputs to adjust fuel quantity and
fuel injector timing. EGR valve control is performed
using feedback from the oxygen sensor. An oxygen
sensor is located in the exhaust manifold to sample
oxygen content exiting the engine cylinders. The
ECM uses the O2 sensor, along with other sensor
inputs, to govern the amount of exhaust gas recir-
culation to reduce HC (HydroCarbons) and CO
(Carbon Monoxide). Engine coolant is routed
through the base of the EGR valve to provide
additional cooling of the exhaust gas, which further
helps the reductions of emissions. The EGR valve
has a self-cleaning function. When the engine is
shut off, the EGR valve rotates twice to reduce
carbon deposits at the valve seat.
Overheat Production Mode
If the engine temperature is above 105ÉC (221ÉF)
and vehicle speed is above 40 km/h (25 MPH) the
ECM will limit fuel quantity for engine protection.
Limp-In Mode
The ECM utilizes different degrees of engine
limp-in. The ECM is able to limit engine rpm,
engine power output (turbo boost reduction), acti-
vate engine cooling fan or all of these functions
based on the type of fault that is detected. Critical
engine performance faults such as accelerator pedal
position sensor fault will result in a fixed idle speed
of approximately 680 rpm regardless of actual pedalposition. Other less critical faults will result in
power reduction throughout the full range of driv-
ing conditions.
Overspeed Detection Mode
If the ECM detects engine RPM that exceeds
5200 RPM, the ECM will set a DTC in memory,
limit engine RPM to no more than 2500 RPM, and
illuminate the MIL until the DTC is cleared.
After-Run Mode
The ECM transfers RAM information to ROM
and performs an Input/Output state check.
3.2.3 MONITORED CIRCUITS
The ECM is able to monitor and identify most
driveability related trouble conditions. Some cir-
cuits are directly monitored through ECM feedback
circuitry. In addition, the ECM monitors the voltage
state of some circuits and compares those states
with expected values. Other systems are monitored
indirectly when the ECM conducts a rationality test
to identify problems.
Although most subsystems of the engine control
module are either directly or indirectly monitored,
there may be occasions when diagnostic trouble
codes are not immediately identified. For a trouble
code to set, a specific set of conditions must occur
and unless these conditions occur, a DTC will not
set.
3.2.4 SKREEM OVERVIEW
The sentry key remote entry module system
(SKREEM) is designed to prevent unauthorized
vehicle operation. The system consists of a sentry
key remote entry module (SKREEM), ignition
key(s) equipped with a transponder chip and the
ECM. When the ignition switch is turned on, the
SKREEM interrogates the ignition key. If the igni-
tion key is Valid or Invalid, the SKREEM sends a
message to the ECM indicating ignition key status.
Upon receiving this message the ECM will termi-
nate engine operation or allow the engine to con-
tinue to operate.
3.2.5 SKREEM ON-BOARD DIAGNOSTICS
The SKREEM has been programmed to transmit
and monitor many different coded messages as well
as CAN Bus messages. This monitoring is called
On-Board Diagnostics. Certain criteria must be met
for a DTC to be entered into SKREEM memory. The
criteria may be a range of; input voltage, CAN Bus
message or coded messages to the SKREEM. If all
the criteria for monitoring a circuit or function are
met and a fault is detected, a DTC will be stored in
the SKREEM memory and the START ERROR indi-
cator will be turned on in the instrument cluster.
2
GENERAL INFORMATION

3.2.6 SKREEM OPERATION
When ignition power is supplied to the SKREEM,
the SKREEM performs an internal self-test. After
the self-test is complete, the SKREEM energizes
the antenna (this activates the transponder chip)
and sends a challenge to the transponder chip. The
transponder chip responds to the challenge by gen-
erating an encrypted response message.
After responding to the coded message, the tran-
sponder sends a transponder ID message to the
SKREEM. The SKREEM compares the transpon-
der ID message to the available valid key codes in
SKREEM memory (8 key maximum at any one
time). After validating the ignition key the
SKREEM sends a CAN Bus message request to the
ECM, then waits for the ECM response. If the ECM
does not respond, the SKREEM will send the re-
quest again. If the ECM does not respond again, the
SKREEM will stop sending the request and store a
trouble code in memory. If the ECM sends a correct
response to the SKREEM, the SKREEM sends a
valid/invalid key message to the ECM. The ECM
will allow or disallow engine operation based on this
message.
Secret Key - an electronically stored value (iden-
tification number) that is unique to each SKREEM.
The secret key is stored in the SKREEM, ECM and
all ignition key transponders.
Challenge - a random number that is generated by
the SKREEM at each ignition key cycle.
The secret key and challenge are the two vari-
ables used in the algorithm that produces the
encrypted response message. The transponder uses
the crypto algorithm to receive, decode and respond
to the message sent by the SKREEM. After re-
sponding to the coded message, the transponder
sends a transponder ID message to the SKREEM.
3.3 DIAGNOSTIC TROUBLE CODES
Each diagnostic trouble code (DTC) is diagnosed
by following a specific procedure. The diagnostic
test procedure contains step-by-step instruction for
determining the cause of the DTC as well as no
trouble code problems. It is not necessary to per-
form all of the tests in this book to diagnose an
individual code.
Always begin diagnosis by reading the DTCs
using the DRBIIIt. This will direct you to the
specific test(s) that must be performed.
3.3.1 HARD CODE
A DTC that comes back within one cycle of the
ignition key is a hard code. This means that the
problem is current every time the ECM/SKREEM
checks that circuit or function. Procedures in this
manual verify if the DTC is a hard code at thebeginning of each test. When the fault is not a hard
code, an intermittent test must be performed.
NOTE: If the DRBIIITdisplays faults for
multiple components (i.e. ECT, MAF, IAT
sensors) identify and check the shared
circuits for possible problems before
continuing (i.e. sensor grounds or 5-volt
supply circuits). Refer to the appropriate
schematic to identify shared circuits.
3.3.2 INTERMITTENT CODE
A DTC that is not current every time the ECM/
SKREEM checks the circuit or function is an inter-
mittent code. Most intermittent DTCs are caused
by wiring or connector problems. Problems that
come and go like this are the most difficult to
diagnose; they must be looked for under specific
conditions that cause them. The following checks
may assist you in identifying a possible intermit-
tent problem.
± Visually inspect the related wire harness con-
nectors. Look for broken, bent, pushed out or
corroded terminals.
± Visually inspect the related wire harness.
Look for chafed, pierced or partially broken
wire.
± Refer to hotlines or technical service bulletins
that may apply.
NOTE: Electromagnetic (radio) interference
can cause an intermittent system
malfunction. This interference can interrupt
communication between the ignition key
transponder and the SKREEM.
3.3.3 ECM DIAGNOSTIC TROUBLE CODES
IMPORTANT NOTE: Before replacing the
ECM for a failed driver, control circuit or
ground circuit, be sure to check the related
component/circuit integrity for failures not
detected due to a double fault in the circuit.
Most ECM driver/control circuit failures are
caused by internal failures to components
(i.e. relays and solenoids) and shorted
circuits (i.e. sensor pull-ups, drivers and
ground circuits). These faults are difficult to
detect when a double fault has occurred and
only one DTC has set.
If the DRBIIItdisplays faults for multiple com-
ponents (i.e. MAF, ECT, ENG OIL, etc.), identify
and check the shared circuits for possible problems
before continuing (i.e. sensor grounds or 5-volt
3
GENERAL INFORMATION