bulb CHRYSLER CARAVAN 2000 Service Manual

The secret key and challenge are plugged into an algorithm that produces the encrypted response
message. The transponder uses the crypto algorithm to receive, decode and respond to the
message sent by 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 SKIM memory (8 key maximum). After validating the key the SKIM sends a
CCD Bus message called a ªSeed Requestº to the body controller then waits for a body controller
response. If the body controller 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 body controller sends a seed response, the SKIM sends a valid/invalid key message to the
body controller. This is an encrypted message that is generated using the following:
VIN þ Vehicle Identification Number
Seed þ This is a random number that is generated by the BCM at each ignition key cycle.
The VIN and seed are plugged into a rolling code algorithm that encrypts the ªvalid/invalid keyº
message. The body controller uses the rolling code algorithm to receive, decode and respond to
the valid/invalid key message sent by SKIM. After sending the valid/invalid key message the SKIM
waits 3.5 seconds for a PCM status message from the body controller. If the BCM does not
respond with a valid key message to the SKIM, a fault is detected and a trouble code stored.
The SKIS incorporates a warning (``ALARM SET'') lamp located in the message center. The lamp
receives switched ignition voltage and is hardwired to the body controller. The lamp is actuated
when the SKIM sends a CCD Bus message to the body controller requesting the lamp on. The
body controller then provides the ground for the lamp. The SKIM will request lamp operation for
the following:
± ± bulb check at ignition on
± to alert the vehicle operator to a SKIS malfunction
For all faults except transponder faults and VIN mismatch, the lamp remains on steady. In the
event of a transponder fault the light flashes at the rate of 1Hz (once per second). If a fault is
present the lamp 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 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 is diagnosed by following a specific testing procedure. The
diagnostic 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 DRB. This procedure begins in
the DTC TEST - Checking the System for Diagnostic Trouble Codes. This will direct you to the
specific test(s) that must be performed.
3.3.1 Hard Code
A diagnostic trouble code that comes back within one cycle of the ignition key is a ªhardº code.
This means that the defect is there every time the engine control module/SKIM checks that circuit
or function. Procedures in this manual verify if the trouble code is a hard code at the beginning
of each test. When it is not a hard code, an ªintermittentº test must be performed.
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TEST TC-26ACONTINUED - REPAIRING - DIAGNOSTIC LAMP OPEN CIRCUIT
*Perform Verification TEST VER-2A. **Check connectors - Clean / repair as necessary.
TEST TC-26A
CONTINUED FROM
THE PREVIOUS TURN IGNITION OFF.
PAGE.
DISCONNECT THE ECM USING AN OHMMETER, REPAIR OPEN
AND MESSAGE CENTER MEASURE RESISTANCE IS THE RESISTANCE YES DIAG/GLOW PLUG
HARNESS OF THE DIAG/GLOW ABOVE 5.0 OHMS? LAMP CONTROL
CONNECTORS.** PLUG LAMP CONTROL CIRCUIT.*
CIRCUIT. FIG.1
NO
USING AN OHMMETER,REPAIR THE
MEASURE ECM HARNESS IS THE RESISTANCE YES DIAG/GLOW PLUG
CONNECTOR CAVITY 24 BELOW 5.0 OHMS? LAMP CONTROL
TO GROUND.CIRCUIT FOR A
FIG.2SHORT TO GROUND.
NO
KEY ON. CONNECT A
RECONNECT THE JUMPER WIRE BETWEEN DID THE DIAG/GLOW YES REPLACE THE ENGINE
MESSAGE CENTER ECM HARNESS PLUG LAMP CONTROL MODULE.*
HARNESS CONNECTOR. CONNECTOR CAVITY 34 ILLUMINATE.
AND GROUND. FIG.2
NO
INSPECT DIAG/GLOWNO REPLACE THE BULB
PLUG LAMP BULB. IS THE BULB OK? AND RETEST.*
YES
REPLACE THE
MESSAGE CENTER.*
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TEST SC-6ACHECKING CRUISE INDICATOR OPERATION
Perform TEST SC-1A Before Proceeding
*Perform Verification TEST VER-3A. **Check connectors - Clean / repair as necessary.
NOTE: PERFORM TEST
START TEST SC-1A TO VERIFY
SC-6A. PROPER CRUISE
SWITCH OPERATION
BEFORE CONTINUING.
TURN IGNITION ON. MONITOR CRUISE DOES LAMP STATE CHECK CRUISE LAMP
WITH THE DRB SELECT LAMP STATE WHILE CHANGE FROM "ON" YES BULB, REPLACE AS
"BODY" "MIC" PRESSING CRUISE TO "OFF" WHEN NECESSARY. IF OK,
"MONITOR DISPLAY" ON/OFF BUTTON PRESSING THE REPLACE THE
THEN "CCD BUS INFO". SEVERAL TIMES. BUTTON? INSTRUMENT CLUSTER.*
NO
KEY OFF. KEY ON. CONNECT A
DISCONNECT THE ECM JUMPER WIRE BETWEEN IS THE SPEED YES REPLACE THE ENGINE
HARNESS ECM HARNESS CONTROL LAMP ON? CONTROL MODULE.*
CONNECTORS.** CONNECTOR CAVITY 30
AND GROUND. FIG.1
NO
KEY OFF. USING AN OHMMETER, REPAIR SHORT TO
DISCONNECT THE BCM MEASURE RESISTANCE IS THE RESISTANCE YES GROUND ON THE
HARNESS BETWEEN ECM HARNESS BELOW 5.0 OHMS? SPEED CONTROL LAMP
CONNECTORS.** CONNECTOR CAVITY 30 CONTROL CIRCUIT.*
AND GROUND. FIG.1
NO
USING AN OHMMETER
MEASURE THE SPEED IS THE RESISTANCE YES REPAIR OPEN SPEED
CONTROL LAMP ABOVE 5.0 OHMS? CONTROL LAMP
CONTROL CIRCUIT. CONTROL CIRCUIT.*
FIG.2
NO
REPLACE THE BODY
CONTROL MODULE.*
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