key CHRYSLER VOYAGER 2001 Service Manual

3.2.3 OTHER CONTROLS
CHARGING SYSTEM
The charging system is turned on when the
engine is started and ASD relay energized. When
the ASD relay is on, ASD output voltage is supplied
to the ASD sense circuit at the PCM. This voltage is
connected in some cases, through the PCM and
supplied to one of the generator field terminals
(Gen Source +). All others, the Gen field is con-
nected directly to the ASD output voltage. The
amount of current produced by the generator is
controlled by the Electronic Voltage Regulator
(EVR) circuitry, in the PCM. Battery temperature is
determined from IAT. This temperature along with
sensed line voltage, is used by the PCM to vary the
battery charging rate. This is done by cycling the
ground path to the other generator field terminal
(Gen field driver).
SPEED CONTROL SYSTEM
The PCM controls vehicle speed by operation of
the speed control servo vacuum and vent solenoids.
Energizing the vacuum solenoid applies vacuum to
the servo to increase throttle position. Operation of
the vent solenoid slowly releases the vacuum allow-
ing throttle position to decrease. A special dump
solenoid allows immediate release of throttle posi-
tion caused by braking, cruise control switch turned
off, shifting into neutral, excessive RPM (tires spin-
ning) or ignition off.
LEAK DETECTION PUMP SYSTEM (IF EQUIPPED)
The leak detection pump is a device that pressur-
izes the evaporative system to determine if there
are any leaks. When certain conditions are met, the
PCM will activate the pump and start counting
pump strokes. If the pump stops within a calibrated
number of strokes, the system is determined to be
normal. If the pump does not stop or stops too soon,
a DTC will be set.
3.2.4 PCM OPERATING MODES
As input signals to the PCM change, the PCM
adjusts its response to output devices. For example,
the PCM must calculate a different injector pulse
width and ignition timing for idle than it does for
wide open throttle. There are several different
modes of operation that determine how the PCM
responds to the various input signals.
There are two types of engine control operation:
open loopandclosed loop.
Inopen loopoperation, the PCM receives input
signals and responds according to preset program-
ming. Inputs from the heated oxygen sensors are
not monitored.Inclosed loopoperation, the PCM monitors the
inputs from the heated oxygen sensors. This input
indicates to the PCM whether or not the calculated
injector pulse width results in the ideal air-fuel
ratio of 14.7 parts air to 1 part fuel. By monitoring
the exhaust oxygen content through the oxygen
sensor, the PCM can fine tune injector pulse width.
Fine tuning injector pulse width allows the PCM to
achieve the lowest emission levels while maintain-
ing optimum fuel economy.
The engine start-up (crank), engine warm-up,
and wide open throttle modes are open loop modes.
Under most operating conditions, closed loop modes
occur with the engine at operating temperature.
IGNITION SWITCH ON (ENGINE OFF) MODE
When the ignition switch activates the fuel injec-
tion system, the following actions occur:
1. The PCM determines atmospheric air pressure
from the MAP sensor input to determine basic
fuel strategy.
2. The PCM monitors the engine coolant tempera-
ture sensor and throttle position sensor input.
The PCM modifies fuel strategy based on this
input.
When the key is in the on position and the engine
is not running (zero rpm), the auto shutdown relay
and fuel pump relay are not energized. Therefore,
voltage is not supplied to the fuel pump, ignition
coil, and fuel injectors.
Engine Start-up ModeÐ This is an open loop
mode. The following actions occur when the starter
motor is engaged:
1. The auto shutdown and fuel pump relays are
energized. If the PCM does not receive the cam-
shaft and crankshaft signal within approxi-
mately one second, these relays are de-
energized.
2. The PCM energizes all fuel injectors until it
determines crankshaft position from the cam-
shaft and crankshaft signals. The PCM deter-
mines crankshaft position within one engine
revolution. After the camshaft position has been
determined, the PCM energizes the fuel injectors
in sequence. The PCM adjusts the injector pulse
width and synchronizes the fuel injectors by
controlling the fuel injectors' ground paths.
3. Once the engine idles within 64 rpm of its target
engine speed, the PCM compares the current
MAP sensor value with the value received dur-
ing the ignition switch on (zero rpm) mode. A
diagnostic trouble code is written to PCM mem-
ory if a minimum difference between the two
values is not found.
4
GENERAL INFORMATION

Once the auto shutdown and fuel pump relays
have been energized, the PCM determines the fuel
injector pulse width based on the following:
± engine coolant temperature
± manifold absolute pressure
± intake air temperature
± engine revolutions
± throttle position
The PCM determines the spark advance based on
the following:
± engine coolant temperature
± crankshaft position
± intake air temperature
± manifold absolute pressure
± throttle position
Engine Warm-Up Modeþ This is an open loop
mode. The PCM adjusts injector pulse width and
controls injector synchronization by controlling the
fuel injectors' ground paths. The PCM adjusts igni-
tion timing and engine idle speed. The PCM adjusts
the idle speed by controlling the idle air control
motor.
Cruise or Idle Modeþ When the engine is at
normal operating temperature, this is a closed loop
mode.
Acceleration Modeþ This is a closed loop mode.
The PCM recognizes an increase in throttle position
and a decrease in Manifold Vacuum as engine load
increases. In response, the PCM increases the in-
jector pulse width to meet the increased load. The
A/C compressor may be de-energized for a short
period of time.
Decelerationþ This is a closed loop mode. The
PCM recognizes a decrease in throttle position and
an increase in Manifold Vacuum as engine load
decreases. In response, the PCM decreases the
injector pulse width to meet the decreased load.
Full injector shut off may be obtained during high
speed deceleration.
Wide Open Throttle Modeþ This is an open
loop mode. The throttle position sensor notifies the
PCM of a wide open throttle condition. Once a wide
open throttle is sensed, the PCM de-energizes the
A/C compressor clutch relay for 20 seconds.
3.2.5 NON-MONITORED CIRCUITS
The PCM does not monitor the following circuits,
systems, and conditions even though they could
have malfunctions that result in driveability prob-
lems. A diagnostic code may not be displayed for the
following conditions. However, problems with these
systems may cause a diagnostic code to be displayed
for other systems. For example, a fuel pressure
problem will not register a diagnostic code directly,
but could cause a rich or lean condition. This couldcause an oxygen sensor, fuel system, or misfire
monitor trouble code to be stored in the PCM.
Engine Timingþ The PCM cannot detect an
incorrectly indexed timing chain, camshaft
sprocket, or crankshaft sprocket. The PCM also
cannot detect an incorrectly indexed distributor.(*)
Fuel Pressureþ Fuel pressure is controlled by
the fuel pressure regulator. The PCM cannot detect
a clogged fuel pump inlet filter, clogged in-line filter,
or a pinched fuel supply.(*)
Fuel Injectorsþ The PCM cannot detect if a fuel
injector is clogged, the pintle is sticking, or the
wrong injectors are installed.(*)
Fuel Requirementsþ Poor quality gasoline can
cause problems such as hard starting, stalling, and
stumble. Use of methanol-gasoline blends may re-
sult in starting and driveability problems. See indi-
vidual symptoms and their definitions in Section
6.0 (Glossary of Terms).
PCM Groundsþ The PCM cannot detect a poor
system ground. However, a diagnostic trouble code
may be stored in the PCM as a result of this
condition.
Throttle Body Air Flowþ The PCM cannot
detect a clogged or restricted air cleaner inlet or
filter element.(*)
Exhaust Systemþ The PCM cannot detect a
plugged, restricted, or leaking exhaust system.(*)
Cylinder Compressionþ The PCM cannot de-
tect uneven, low, or high engine cylinder compres-
sion.(*)
Excessive Oil Consumptionþ Although the
PCM monitors the exhaust stream oxygen content
through the oxygen sensor when the system is in a
closed loop, it cannot determine excessive oil con-
sumption.
NOTE: ANY OF THESE CONDITIONS
COULD RESULT IN A RICH OR LEAN
CONDITION CAUSING AN OXYGEN SENSOR
TROUBLE CODE TO BE STORED IN THE
PCM, OR THE VEHICLE MAY EXHIBIT ONE
OR MORE OF THE DRIVEABILITY
SYMPTOMS LISTED IN THE TABLE OF
CONTENTS.
3.2.6 SKIS OVERVIEW
The Sentry Key Immobilizer System (SKIS) is
designed to prevent unauthorized vehicle opera-
tion. The system consists of a Sentry Key Immobi-
lizer Module (SKIM), ignition key(s) equipped with
a transponder chip and PCM. When the ignition
switch is turned on, the SKIM interrogates the
ignition key. If the ignition key is Valid or Invalid,
the SKIM sends a PCI Bus message to the PCM
indicating ignition key status. Upon receiving this
5
GENERAL INFORMATION

message the PCM will terminate engine operation,
or allow the engine to continue to operate.
3.2.7 SKIM ON-BOARD DIAGNOSTICS
The SKIM has been programmed to transmit and
monitor many different coded messages as well as
PCI Bus messages. This monitoring is called On
Board Diagnosis.
Certain criteria must be met for a diagnostic
trouble code to be entered into the SKIM memory.
The criteria may be a range of; Input voltage, PCI
Bus message, or coded messages to the SKIM. If all
of the criteria for monitoring a circuit or function
are met and a fault is sensed, a diagnostic trouble
code will be stored in the SKIM memory.
3.2.8 SKIS OPERATION
When ignition power is supplied to the SKIM, the
SKIM performs an internal self-test. After the self-
test is completed, the SKIM energizes the antenna
(this activates the transponder chip) and sends a
challenge to the transponder chip. The transponder
chip responds to the challenge by generating an
encrypted response message using the following:
Secret Key -This is an electronically stored
value (identification number) that is unique to each
SKIS. The secret key is stored in the SKIM, PCM
and all ignition key transponders.
Challenge- This is a random number that is
generated by the SKIM 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 SKIM. After responding
to the coded message, the transponder sends a
transponder I.D. message to the SKIM. The SKIM
compares the transponder I.D. to the available valid
key codes in the SKIM memory (8 key maximum at
any one time). After validating the key ignition the
SKIM sends a PCI Bus message called a Seed
Request to the engine controller then waits for a
PCM response. If the PCM does not respond, the
SKIM will send the seed request again. After three
failed attempts the SKIM will stop sending the seed
request and store a trouble code. If the PCM sends
a seed response, the SKIM sends a valid/invalid key
message to the PCM. 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 PCM 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 PCM uses the rolling code
algorithm to receive, decode and respond to the
valid/invalid key message sent by the SKIM. Aftersending the valid/invalid key message the SKIM
waits 3.5 seconds for a PCM status message from
the PCM. If the PCM does not respond with a valid
key message to the SKIM, a fault is detected and a
trouble code is stored.
The SKIS incorporates a VTSS LED located on
the instrument panel upper cover. The LED re-
ceives switched ignition voltage and is hardwired to
the body control module. The LED is actuated when
the SKIM sends a PCI Bus message to the body
controller requesting the LED on. The body control-
ler then provides the ground for the LED. The
SKIM 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 SKIM memory which prevents the
system from operating properly, the PCM will allow
the engine to start and run (for 2 seconds) up to six
times. After the sixth attempt, the PCM disables
the starter relay until the fault is corrected.
3.2.9 PROGRAMMING THE POWERTRAIN
CONTROL MODULE
Important Note:Before replacing the PCM for a
failed driver, control circuit or ground circuit, be
sure to check the related component/circuit integ-
rity for failures not detected due to a double fault in
the circuit. Most PCM driver/control circuit failures
are caused by internal failure to components (i.e.
12-volt pull-ups, drivers and ground sensors). These
failures are difficult to detect when a double fault
has occurred and only one DTC has set.
NOTE: IF THE PCM AND THE SKIM ARE
REPLACED AT THE SAME TIME, PROGRAM
THE VIN INTO THE PCM FIRST. ALL VEHICLE
KEYS WILL THEN NEED TO BE REPLACED
AND PROGRAMMED TO THE NEW SKIM.
The SKIS Secret Key is an I.D. code that is
unique to each SKIS. This code is programmed and
stored in the SKIM, engine controller and transpon-
der chip (ignition key). When replacing the PCM it
is necessary to program the secret key into the
PCM.
1. Turn the ignition on (transmission in park/
neutral).
2. Use the DRB and select THEFT ALARM, SKIM
then MISCELLANEOUS.
6
GENERAL INFORMATION

3. Select PCM REPLACED.
4. Enter secured access mode by entering the vehi-
cle four-digit PIN.
NOTE: IF THREE ATTEMPTS ARE MADE TO
ENTER THE SECURE ACCESS MODE USING
AN INCORRECT PIN, SECURED ACCESS
MODE WILL BE LOCKED OUT FOR ONE
HOUR. TO EXIT THIS LOCKOUT MODE,
TURN THE IGNITION TO THE RUN POSITION
FOR ONE HOUR THEN ENTER THE
CORRECT PIN. (ENSURE ALL ACCESSORIES
ARE TURNED OFF. ALSO MONITOR THE
BATTERY STATE AND CONNECT A BATTERY
CHARGER IF NECESSARY).
5. Press ENTER to transfer the secret key (the
SKIM will send the secret key to the PCM).
3.2.10 PROGRAMMING THE SENTRY KEY
IMMOBILIZER MODULE
NOTE: IF THE PCM AND THE SKIM ARE
REPLACED AT THE SAME TIME, PROGRAM
THE VIN INTO THE PCM FIRST. ALL VEHICLE
KEYS WILL THEN NEED TO BE REPLACED
AND PROGRAMMED TO THE NEW SKIM.
1. Turn the ignition on (transmission in park/
neutral).
2. Use the DRB and select THEFT ALARM, SKIM
then MISCELLANEOUS.
3. Select SKIM MODULE REPLACEMENT (GAS-
OLINE).
4. Program the vehicle four-digit PIN into the
SKIM.
5. Select COUNTRY CODE and enter the correct
country.
NOTE: BE SURE TO ENTER THE CORRECT
COUNTRY CODE. IF THE INCORRECT
COUNTRY CODE IS PROGRAMMED INTO
SKIM, THE SKIM MUST BE REPLACED.
6. Select UPDATE VIN (the SKIM will learn the
VIN from the PCM).
7. Press ENTER to transfer the VIN (the PCM will
send the VIN to the SKIM).
8. The DRB will ask if you want to transfer the
secret key. Select ENTER to transfer secret key
from the PCM. This will ensure the current
vehicle ignition keys will still operate the SKIS
system.
3.2.11 PROGRAMMING THE IGNITION
KEYS TO THE SENTRY KEY
IMMOBILIZER MODULE
1. Turn the ignition on (transmission in park/
neutral).
2. Use the DRB and select THEFT ALARM, SKIM,
then MISCELLANEOUS.
3. Select PROGRAM IGNITION KEYS.
4. Enter secured access mode by entering the vehi-
cle four-digit PIN.
NOTE: A MAXIMUM OF EIGHT KEYS CAN BE
LEARNED TO EACH SKIM AT ONE TIME.
ONCE A KEY IS LEARNED TO A SKIM IT (THE
KEY) CANNOT BE TRANSFERRED TO
ANOTHER VEHICLE.
If ignition key programming is unsuccessful, the
DRB will display one of the following messages:
Programming Not Attempted- The DRB at-
tempts to read the programmed key status and
there are no keys programmed in the SKIM mem-
ory.
Programming Key Failed -(Possible Used Key
From Wrong Vehicle) - SKIM is unable to program
key due to one of the following:
± faulty ignition key transponder
± ignition key is programmed to another vehicle.
8 Keys Already Learned, Programming Not
Done- SKIM transponder ID memory is full.
1. Obtain ignition keys to be programmed from
customer (8 keys maximum)
2. Using the DRB, erase all ignition keys by select-
ing MISCELLANEOUS and ERASE ALL CUR-
RENT IGN. KEYS
3. Program all ignition keys.
Learned Key In Ignition- Ignition key transpon-
der ID is currently programmed in SKIM memory.
3.3 DIAGNOSTIC TROUBLE 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 trouble codes as well as
no trouble code problems. 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 using the DRBIIIt.
3.3.1 HARD CODE
A diagnostic trouble code that comes back within
one cycle of the ignition key is a hard code. This
means that the defect is there every time the
7
GENERAL INFORMATION

powertrain control module checks that circuit or
function. Procedures in this manual verify if the
DTC is a hard code at the beginning of each test.
When it is not a hard code, an intermittent test
must be performed.
DTC's that are for Euro Stage III OBD monitors
will not set with just the ignition key on. Comparing
these to non-emission DTC's, they will seem like an
intermittent. These DTC's require a set of parame-
ters to be performed (The DRBIIItpre-test screens
will help with this for MONITOR DTC's), this is
called a TRIP. All Euro Stage III OBD DTCs will be
set after one or in some cases two trip failures, and
the MIL will be turned on. These DTC's require
three successful, no failures, TRIPS to extinguish
the MIL, followed by 40 warm-up cycles to erase the
DTC.
3.3.2 INTERMITTENT CODE
A diagnostic trouble code that is not there every
time the PCM checks the circuit is an intermittent
DTC. Most intermittent DTC's are caused by wiring
or connector problems. Defects 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 intermittent problem:
²Visually inspect related wire harness connectors.
Look for broken, bent, pushed out, or corroded
terminals.
²Visually inspect the related harnesses. Look for
chafed, pierced, or partially broken wire.
²Refer to any technical service bulletins that may
apply.
²Use the DRBIIItdata recorder or co-pilot.
3.3.3 DISTANCE SINCE MI SET
The Euro Stage III OBD directive requires that
the distance traveled by the vehicle while theMIis
activated must be available at any instant through
the serial port on the standard data link connector.
This feature works as follows:1. If the MI is illuminated due to a fault, the
distance count is updated (i.e. it is counting).
2. If there is a9stale9MI fault (i.e. the fault is still
frozen in memory but the MI has heen extin-
guished due to 3 good trips), the distance count is
held (i.e. frozen).
3. If the distance count is being held due to (Item
2.) and the fault is cleared, the distance is
cleared (set to zero).
4. If the distance count is being held due to (Item
2.) and another MI occurs, the distance count is
reset (to 0) and begins updating anew.
5. If a fault occurs while the MI is already illumi-
nated due to a previous fault (the distance count
is updating), then the distance count continues
to update w/out interruption.
6. If the MI is flashing due to activate misfire and
there is and9active9fault (i.e. matured fault for
which 3 good trips have not occurred), the dis-
tance count behaves as the MI in ON.
7. If the MI is flashing due to active misfire and
there is no9active9fault (i.e. the MI is flashing
for a 1 malf.), the distance count behaves as if
the MI is off (because it is not yet a matured
fault).
8. The distance count is cleared whenever the fault
is cleared. (Via 40 warm up cycles, or via scan
tool).
3.3.4 HANDLING NO DTC PROBLEMS
Symptom checks cannot be used properly unless
the driveability problem characteristic actually
happens while the vehicle is being tested.
Select the symptom that most accurately de-
scribes the vehicle's driveability problem and then
perform the test routine that pertains to this symp-
tom. Perform each routine test in sequence until the
problem is found. For definitions, see Section 6.0
Glossary Of Terms.
SYMPTOM DIAGNOSTIC TEST
HARD START CHECKING THE FUEL PRESSURE
CHECKING THE ECT SENSOR
CHECKING THROTTLE POSITION SENSOR
CHECKING MAP SENSOR
CHECKING IDLE AIR CONTROL MOTOR OPERATION
CHECKING EGR SYSTEM
CHECKING IAT SENSOR
8
GENERAL INFORMATION

SYMPTOM DIAGNOSTIC TEST
POOR FUEL ECONOMY CHECKING PCM POWER AND GND CKT
CHECKING THE FUEL PRESSURE
CHECKING ECT SENSOR
CHECKING THROTTLE POSITION SENSOR
CHECKING MAP SENSOR
CHECKING IDLE AIR CONTROL MOTOR OPERATION
CHECKING IAT SENSOR
3.4 USING THE DRBIIIT
Refer to the DRBIIItuser 's guide for instructions
and assistance with reading DTC's, erasing DTC's,
and other DRBIIItfunctions.
3.5 DRBIIITERROR MESSAGES AND
BLANK SCREEN
Under normal operation, the DRBIIItwill dis-
play one of only two error messages:
± User-Requested WARM Boot or User-
Requested COLD Boot
ver: 2.14
date: 26 Jul93
file: key_itf.cc
date: Jul 26 1993
line: 548
err: 0x1
User-Requested COLD Boot
Press MORE to switch between this display
and the application screen.
Press F4 when done noting information.
3.5.1 DRBIIITDOES NOT POWER UP
If the LED's 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 (data link
connector cavity 16). A minimum of 11 volts is
required to adequately power the DRBIIIt.
If all connections are proper between the
DRBIIItand the vehicle or other devices, and the
vehicle battery is fully charged, and inoperative
DRBIIItmay be the result of faulty cable or vehicle
wiring.
3.5.2 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.
4.2 SAFETY
4.2.1 TECHNICIAN SAFETY INFORMATION
WARNING: ENGINES PRODUCE CARBON
MONOXIDE THAT IS ODORLESS, CAUSES
SLOWER REACTION TIME, AND CAN LEAD
TO SERIOUS INJURY. WHEN THE ENGINE IS
OPERATING, KEEP SERVICE AREAS WELL
VENTILATED OR ATTACH THE VEHICLE
EXHAUST SYSTEM TO THE SHOP EXHAUST
REMOVAL SYSTEM.
Set the parking brake and block the wheels before
testing or repairing the vehicle. It is especially
10
GENERAL INFORMATION

rough,
unstable,
or er-
ratic idle
stallingThe engine runs unevenly at idle
and causes the engine to shake if it
is severe enough. The engine idle
rpm may vary (called hunting). This
condition may cause stalling if it is
severe enough.
SBECsingle board engine controller
SKIMsentry key immobilizer module
SKISsentry key immobilizer systemstart &
stallThe engine starts but immediately
dies.
surgeengine rpm fluctuation without cor-
responding change in throttle posi-
tion sensor
TPSthrottle position sensor
TRStransmission range sensor
VSSvehicle speed sensor/signal
13
GENERAL INFORMATION

Symptom List:
P0600-PCM FAILURE SPI COMMUNICATIONS
P0601-PCM INTERNAL CONTROLLER FAILURE
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P0600-PCM FAILURE SPI
COMMUNICATIONS.
When Monitored and Set Condition:
P0600-PCM FAILURE SPI COMMUNICATIONS
When Monitored: Ignition key on.
Set Condition: Internal Bus communication failure between processors.
P0601-PCM INTERNAL CONTROLLER FAILURE
When Monitored: Ignition key on.
Set Condition: Internal checksum for software failed, does not match calculated value.
POSSIBLE CAUSES
PCM INTERNAL OR SPI
TEST ACTION APPLICABILITY
1 The Powertrain Control Module is reporting internal errors, view repair to continue. All
Repair
Replace and program the Powertrain Control Module in accor-
dance with the Service Information.
Perform POWERTRAIN VERIFICATION TEST VER-1.
23
COMMUNICATION

Symptom:
P1685-WRONG OR INVALID KEY MSG RECEIVED FROM SKIM
When Monitored and Set Condition:
P1685-WRONG OR INVALID KEY MSG RECEIVED FROM SKIM
When Monitored: With the ignition on.
Set Condition: The PCM does not receive a Valid Key message from the SKIM.
POSSIBLE CAUSES
INCORRECT VIN IN PCM
INVALID SKIM KEY NOT PRESENT
NO COMMUNICATION WITH SKIM
NO VIN PROGRAMMED IN THE PCM
PCM
SKIM TROUBLE CODES SET
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB III, read the PCM DTCs. Look for P1685.
Is the Starts Since Set counter for DTC P1685 displayed and equal to 0?All
Ye s®Go To 2
No®Go To 7
2 With the DRB III, attempt to communicate with the SKIM.
Turn the ignition on.
Can the DRB III communicate with the SKIM?All
Ye s®Go To 3
No®Refer to symptom BUS +/- SIGNAL OPEN FROM SKIM in the
COMMUNICATION category.
3 Turn the ignition on.
With the DRB III, check for SKIM DTCs.
Are any DTCs present in the SKIM?All
Ye s®Repair all SKIM DTCs.
Perform SKIS VERIFICATION TEST.
No®Go To 4
4 Turn the ignition on.
With the DRB III, display the VIN that is programmed in the PCM.
Has a VIN been programmed into the PCM?All
Ye s®Go To 5
No®Program the correct VIN into the PCM and retest.
Perform SKIS VERIFICATION TEST.
24
COMMUNICATION

TEST ACTION APPLICABILITY
5 Turn the ignition on.
With the DRB III, display the VIN that is programmed in the PCM.
Was the correct VIN programmed into the PCM?All
Ye s®Go To 6
No®Replace and program the Powertrain Control Module in accor-
dance with the Service Information.
Perform SKIS VERIFICATION TEST.
6 Turn the ignition off.
Replace and program the Sentry Key Immobilizer Module in accordance with the
Service Information.
Turn the ignition on.
With the DRB III, erase all SKIM and PCM DTCs.
Attempt to start and idle the engine.
With the DRB III, read the PCM DTCs.
Does the DRB III display this code?All
Ye s®Replace and program the Powertrain Control Module in accor-
dance with the Service Information.
Perform SKIS VERIFICATION TEST.
No®Test Complete.
7NOTE: This DTC could have been set if the SKIM harness connector was
disconnected, or if the SKIM was replaced recently.
NOTE: All keys that the customer uses for this vehicle must be tested to
verify they are operating properly.
Turn the ignition on.
Verify the correct VIN is programmed into the PCM and SKIM.
Turn the ignition off.
With the next customer key turn the ignition key on and crank the engine to start.
With the DRB III, read the PCM DTCs. Look for P1685
Is the Starts Since Set counter for DTC P1685 displayed and equal to 0?All
Ye s®Replace the Ignition Key.
Perform SKIS VERIFICATION TEST.
No®Test Complete.
NOTE: If this DTC cannot be reset, it could have been an actual theft
attempt.
25
COMMUNICATION
P1685-WRONG OR INVALID KEY MSG RECEIVED FROM SKIM Ð
Continued