Chrysler RG Voyager. Manual — part 375

SKREES. The secret key is stored in the SKREEM,
ECM and all ignition key transponders.

Challenge - This is 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 I.D. message to the SKREEM.
The SKREEM compares the transponder I.D. to the
available valid key codes in the SKREEM memory
(8 key maximum at any one time). After validating
the key ignition the SKREEM sends a PCI Bus
message called a Seed Request to the engine con-
troller then waits for a ECM response. If the ECM
does not respond, the SKREEM will send the seed
request again. After three failed attempts the
SKREEM will stop sending the seed request and
store a trouble code. If the ECM sends a seed
response, the SKREEM sends a valid/invalid key
message to the ECM. This is an encrypted message
that is generated using the following:

VIN - Vehicle Identification Number
Seed - This is a random number that is generated

by the ECM at each ignition key cycle.

The VIN and seed are the two variables used in

the rolling code algorithm that encrypts the valid/
invalid key message. The ECM uses the rolling code
algorithm to receive, decode and respond to the
valid/invalid key message sent by the SKREEM.
After sending the valid/invalid key message the
SKREEM waits 3.5 seconds for a ECM status
message from the ECM. If the ECM does not
respond with a valid key message to the SKREEM,
a fault is detected and a trouble code is stored.

The SKREES incorporates a VTSS LED located

on the instrument panel upper cover. The LED
receives switched ignition voltage and is hardwired
to the body control module. The LED is actuated
when the SKREEM sends a PCI Bus message to the
body controller requesting the LED on. The body
controller then provides the ground for the LED.
The SKREEM will request VTSS LED operation for
the following:

– bulb checks at ignition on

– to alert the vehicle operator to a SKIS mal-

function

– customer key programming mode

For all faults except transponder faults and VTSS

LED remains on steady. In the event of a transpon-
der fault the LED flashes at a rate of 1 Hz (once per
second). If a fault is present the LED will remain on
or flashing for the complete ignition cycle. If a fault

is stored in SKREEM memory which prevents the
system from operating properly, the ECM will allow
the engine to start and run (for 2 seconds) up to six
times. After the sixth attempt, the ECM disables
the starter relay until the fault is corrected.

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 DRBIII

t. 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 the
beginning of each test. When the fault is not a hard
code, an intermittent test must be performed.
NOTE: If the DRBIII

t displays faults for multiple

components (i.e. ECT, VSS, 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 connec-
tors. Look for broken, bent, pushed out, or cor-
roded 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 SKREES malfunction. This
interference can interrupt communication between
the ignition key transponder and the SKREEM.

3

GENERAL INFORMATION

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 in-
tegrity for failures not detected due to a double fault
in the circuit. Most ECM driver/control circuit fail-
ures 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 DRBIII

t displays faults for multiple com-

ponents (i.e. VSS, ECT, Batt Temp, etc.), identify
and check the shared circuits for possible problems
before continuing (i.e. sensor grounds or 5-volt
supply circuits). Refer to the appropriate wiring
diagrams to identify shared circuits.

A/C CLUTCH RELAY CIRCUIT OPEN CIRCUIT
A/C CLUTCH RELAY CIRCUIT SHORT CIR-

CUIT

A/C PRESSURE SENSOR CIRCUIT PLAUSI-

BILITY

A/C PRESSURE SENSOR CIRCUIT SIGNAL

VOLTAGE TOO HIGH

A/C PRESSURE SENSOR CIRCUIT SIGNAL

VOLTAGE TOO LOW

A/C PRESSURE SENSOR CIRCUIT SUPPLY

VOLTAGE TOO HIGH OR LOW

ACC PEDAL POSITION SENSOR 1 CKT PLAU-

SIBILITY

ACC PEDAL POSITION SENSOR 1 CKT PLAU-

SIBILITY WITH BRAKE SWITCH

ACC PEDAL POSITION SENSOR 1 CKT PLAU-

SIBILITY WITH POTENTIOMETER

ACC PEDAL POSITION SENSOR 1 CKT SIG-

NAL VOLTAGE TOO HIGH

ACC PEDAL POSITION SENSOR 1 CKT SIG-

NAL VOLTAGE TOO LOW

ACC PEDAL POSITION SENSOR 1 CKT SUP-

PLY VOLTAGE TOO HIGH OR LOW

AFTER RUN SHUT OFF ERROR-INJ. POWER-

STAGE

AFTER RUN SHUT OFF ERROR-ZERO QUAN-

TITY

BAROMETRIC PRESSURE CIRCUIT SIGNAL

VOLTAGE TOO HIGH

BAROMETRIC PRESSURE CIRCUIT SIGNAL

VOLTAGE TOO LOW

BATTERY SENSE LINE 1 VOLTAGE TOO

HIGH

BATTERY SENSE LINE 1 VOLTAGE TOO LOW
BATTERY SENSE LINE 2 VOLTAGE TOO

HIGH

BATTERY SENSE LINE 2 VOLTAGE TOO LOW
BATTERY TEMP SENSOR CIRCUIT SIGNAL

VOLTAGE TOO HIGH

BOOST PRESSURE SENSOR PLAUSIBILITY

BOOST PRESSURE SENSOR SIGNAL VOLT-

AGE TOO HIGH

BOOST PRESSURE SENSOR SIGNAL VOLT-

AGE TOO LOW

BOOST PRESSURE SENSOR SUPPLY VOLT-

AGE TOO HIGH OR LOW

BRAKE SWITCH SIGNAL CIRCUITS PLAUSI-

BILITY AFTER INIT.

BRAKE SWITCH SIGNAL CIRCUITS PLAUSI-

BILITY WITH REDUNDANT CONTACT

CALCULATED

INJECTOR

VOLTAGE

TOO

HIGH

CALCULATED

INJECTOR

VOLTAGE

TOO

LOW

CAPACITOR VOLTAGE 1 VOLTAGE TOO HIGH
CAPACITOR VOLTAGE 1 VOLTAGE TOO LOW
CKP POSITION SENSOR CIRCUIT OVER-

SPEED RECOGNITION

CLUTCH UPSTOP SWITCH PERF PLAUSIBIL-

ITY

CLUTCH

PEDAL

SW

OVERRIDE

RELAY

SHORT CIRCUIT

CMP POSITION SENSOR CIRCUIT CMP/CKP

SYNC FAILURE

CMP POSITION SENSOR CIRCUIT DYNAMIC

PLAUSIBILITY

CMP POSITION SENSOR CIRCUIT SIGNAL

FREQUENCY TOO HIGH

CMP POSITION SENSOR CIRCUIT STATIC

PLAUSIBILITY

CYLINDER 1-INJECTOR CIRCUIT CURRENT

DECREASE

CYLINDER 1-INJECTOR

CIRCUIT

LOAD

DROP

CYLINDER 1-INJECTOR CIRCUIT OVERCUR-

RENT HIGH SIDE

CYLINDER 1-INJECTOR CIRCUIT OVERCUR-

RENT LOW SIDE

CYLINDER 2-INJECTOR CIRCUIT CURRENT

DECREASE

CYLINDER 2-INJECTOR

CIRCUIT

LOAD

DROP

CYLINDER 2-INJECTOR CIRCUIT OVERCUR-

RENT HIGH SIDE

CYLINDER 2-INJECTOR CIRCUIT OVERCUR-

RENT LOW SIDE

CYLINDER 3-INJECTOR CIRCUIT CURRENT

DECREASE

CYLINDER 3-INJECTOR

CIRCUIT

LOAD

DROP

CYLINDER 3-INJECTOR CIRCUIT OVERCUR-

RENT HIGH SIDE

CYLINDER 3-INJECTOR CIRCUIT OVERCUR-

RENT LOW SIDE

CYLINDER 4-INJECTOR CIRCUIT CURRENT

DECREASE

CYLINDER 4-INJECTOR

CIRCUIT

LOAD

DROP

4

GENERAL INFORMATION

CYLINDER 4-INJECTOR CIRCUIT OVERCUR-

RENT HIGH SIDE

CYLINDER 4-INJECTOR CIRCUIT OVERCUR-

RENT LOW SIDE

ECM ERROR - COMMUNICATION NOT VERI-

FIED

ECM ERROR GATE ARRAY - COMMUNICA-

TION

ECM ERROR GATE ARRAY - QUANTITY STOP
ECM ERROR RECOVERY HAS OCCURRED
ECM ERROR REDUNDANT OVERRUN MONI-

TORING

ECM/PCM RELAY CONTROL CIRCUIT SHUTS

OFF TOO EARLY

ECM/PCM RELAY CONTROL CIRCUIT SHUTS

OFF TOO LATE

EEPROM MEMORY WRITE DENIED
EEPROM PLAUSIBILITY

CHECKSUM

ER-

ROR

EEPROM PLAUSIBILITY CODE WORD IN-

CORRECT OR MISSING

EEPROM PLAUSIBILITY COMMUNICATION

ERROR

EEPROM PLAUSIBILITY VARIATION NUM-

BER ERROR

EEPROM PLAUSIBILITY VIN CHECKSUM

ERROR

EEPROM PLAUSIBILITY WRITE ERROR
EGR SOLENOID CIRCUIT OPEN CIRCUIT
EGR SOLENOID CIRCUIT SHORT CIRCUIT
ENGINE COOLANT TEMP SENSOR CIRCUIT

SIGNAL VOLTAGE TOO HIGH

ENGINE COOLANT TEMP SENSOR CIRCUIT

SIGNAL VOLTAGE TOO LOW

FAN 1 CONTROL CIRCUIT OPEN CIRCUIT
FAN 1 CONTROL CIRCUIT SHORT CIRCUIT
FAN 2 CONTROL CIRCUIT OPEN CIRCUIT
FAN 2 CONTROL CIRCUIT SHORT CIRCUIT
FUEL PRESS SENSOR CIRCUIT MALF SIG-

NAL VOLTAGE TOO HIGH

FUEL PRESS SENSOR CIRCUIT MALF SIG-

NAL VOLTAGE TOO LOW

FUEL PRESS SENSOR CIRCUIT MALF SUP-

PLY VOLTAGE TOO HIGH OR LOW

FUEL PRESSURE SOLENOID OPEN CIRCUIT
FUEL PRESSURE SOLENOID PLAUSIBILITY

IN AFTER-RUN

FUEL PRESSURE SOLENOID SHORT CIR-

CUIT

FUEL

RAIL

PRESSURE

MALFUNCTION

LEAKAGE DETECTED

FUEL

RAIL

PRESSURE

MALFUNCTION

PRESSURE TOO HIGH - SHUT OFF

FUEL

RAIL

PRESSURE

MALFUNCTION

PRESSURE TOO LOW

FUEL RAIL PRESSURE MALFUNCTION SO-

LENOID OPEN

GENERATOR FIELD CONTROL MALF BAT-

TERY VOLTAGE DEVIATION TOO HIGH

GENERATOR FIELD CONTROL MALF BAT-

TERY VOLTAGE DEVIATION TOO LOW

GENERATOR FIELD CONTROL MALF BAT-

TERY VOLTAGE TOO HIGH

GENERATOR FIELD CONTROL MALF BAT-

TERY VOLTAGE TOO LOW

GENERATOR

FIELD

CONTROL

MALF

CHARGING VOLTS TOO LOW

GENERATOR FIELD CONTROL MALF OPEN

CIRCUIT

GENERATOR FIELD CONTROL MALF SHORT

CIRCUIT

GENERATOR FIELD CONTROL MALF UN-

STABLE CURRENT

GLOW PLUG 1 CONTROL CIRCUIT OPEN

CIRCUIT

GLOW PLUG 1 CONTROL CIRCUIT SHORT

CIRCUIT

IGNITION SWITCH PLAUSIBILITY
INTAKE AIR TEMP SENSOR CIRCUIT SIG-

NAL VOLTAGE TOO HIGH

INTAKE AIR TEMP SENSOR CIRCUIT SIG-

NAL VOLTAGE TOO LOW

LIFT PUMP RELAY CONTROL CIRCUIT OPEN

CIRCUIT

LIFT

PUMP

RELAY

CONTROL

CIRCUIT

SHORT CIRCUIT

MASS AIR FLOW SENSOR PLAUSIBILITY
MASS AIR FLOW SENSOR PLAUSIBILITY

POSITIVE AREA

MASS AIR FLOW SENSOR SIGNAL VOLTAGE

TOO HIGH

MASS AIR FLOW SENSOR SIGNAL VOLTAGE

TOO LOW

MASS AIR FLOW SENSOR SUPPLY VOLTAGE

TOO HIGH OR LOW

OIL PRESS SENSOR CKT MALF PLAUSIBIL-

ITY

OIL PRESS SENSOR CKT MALF SUPPLY

VOLTAGE TOO HIGH OR LOW

SENSOR REFERENCE VOLTAGE A CKT VOLT-

AGE TOO HIGH

SENSOR REFERENCE VOLTAGE A CKT VOLT-

AGE TOO LOW

SENSOR

REFERENCE

VOLTAGE

B

CKT

VOLTAGE TOO HIGH

SENSOR

REFERENCE

VOLTAGE

B

CKT

VOLTAGE TOO LOW

SKIM SYSTEM INVALID KEY CODE RE-

CEIVED

SKIM SYSTEM INVALID SECRET KEY IN EE-

PROM

SKIM

SYSTEM

KEY

COMMUNICATION

TIMED OUT

SKIM SYSTEM SKIM ERROR

5

GENERAL INFORMATION

SKIM SYSTEM WRITE ACCESS TO EEPROM

FAILURE

STARTER RELAY CIRCUIT SHORT CIRCUIT
SYSTEM VOLTAGE TOO HIGH
SYSTEM VOLTAGE TOO LOW
VEHICLE SPEED SENSOR FREQUENCY TOO

HIGH

VEHICLE SPEED SENSOR HIGH LEVEL DU-

RATION

VEHICLE SPEED SENSOR PLAUSIBILITY
VEHICLE SPEED SENSOR SIGNAL VOLTAGE

TOO HIGH

VOLTAGE REGULATOR SIGNAL VOLTAGE

TOO HIGH

VOLTAGE REGULATOR SIGNAL VOLTAGE

TOO LOW

3.3.4

SKIM DIAGNOSTIC TROUBLE CODES

ANTENNA FAILURE
COP FAILURE
EEPROM FAILURE
INTERNAL FAULT
NO BCM COMMUNICATION
PCM STATUS FAILURE
RAM FAILURE
ROLLING CODE FAILURE
ROM FAULT
SERIAL LINK EXTERNAL FAULT
SERIAL LINK INTERNAL FAULT
STACK OVERFLOW FAILURE
TRANSPONDER COMMUNICATION FAILURE
TRANSPONDER ID MISMATCH
TRANSPONDER RESPONSE MISMATCH
UNPROGRAMMED SKREEM
VIN MISMATCH

3.3.5

HANDLING NO TROUBLE CODE
PROBLEMS

After reading Section 3.0 (System Description

and Functional Operation), you should have a bet-
ter understanding of the theory and operation of the
on-board diagnostics and how this relates to the
diagnosis of a vehicle that may have a driveability-
related symptom or complaint. When there are no
trouble codes present, refer to the no trouble code
(*) tests.

3.4

USING THE DRBIII

T

Refer to the DRBIII

t user’s guide for instructions

and assistance with reading the DTCs, erasing the
DTCs, lab scope usage and other DRBIII

t func-

tions.

3.4.1

DRBIII

T DOES NOT POWER UP

If the LEDs do not light or no sound is emitted at

start up, check for loose cable connections or a bad
cable. Check the vehicle battery voltage at data link
connector cavity 16. A minimum of 11.0 volts is
required to adequately power the DRBIII

t. Check

for proper ground connection at data link connector
cavities 4 and 5.

If all connections are proper between the

DRBIII

t and the vehicle or other devices, and the

vehicle battery is fully charged, an inoperative
DRBIII

t may be the result of a faulty cable or

vehicle wiring. For a blank screen, refer to the
appropriate diagnostic manual.

3.4.2

DISPLAY IS NOT VISIBLE

Low temperatures will affect the visibility of the

display. Adjust the contrast to compensate for this
condition.

4.0

DISCLAIMERS, SAFETY,
WARNINGS

4.1

DISCLAIMERS

All information, illustrations, and specifications

contained in this manual are based on the latest
information available at the time of publication.
The right is reserved to make changes at any time
without notice.

6

GENERAL INFORMATION