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2000 Chrysler LHS Question: replacing BCM

 

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frosty, 3.5L V6, Colorado Springs, CO, August 30, 2010, 10:15
 Rookie

I am sure by information I received through this site that the BCM is bad. I did a power reset by disconnecting the + battery cable at the positive jump start terminal. That did not change the symptoms. I bought a used BCM but I have read that the BCM must match serial number or a model number?? Any truth to this? Also, I was told if I put in one that does not match my car, it will disable some systems and may never start until a dealer recodes the computers. Please provide some truth to this.

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  • Medium-star Best Answer
    Johnny Mopar August 31, 2010, 11:17
     Master

    This is true that you must replace the BCM with the same Model year and Part number. Also if the VIN programmed in the BCM does not match your vehicles VIN, many of the BCM functions will not work and yes, if your vehicle is equipped with a vehicle theft alarm, it will not start Here are some of the things the BCM controls.
    BODY CONTROL MODULE
    The body control module (BCM) supplies vehicle
    occupants with visual and audible information and
    controls various vehicle functions. To provide and
    receive information, the module is interfaced to the
    vehicle’s serial bus communications network (the
    Programmable Communication Interface or PCI
    bus). This network consists of the powertrain control
    module (PCM), the memory heat seat/mirror
    module (MHSMM), sentry key immobilizer module
    (SKIM), the transmission control module (TCM),
    the electro/mechanical instrument cluster (MIC),
    the optional overhead travel information system
    (OTIS), airbag control module (ACM), optional antilock
    brakes (ABS), the radio and the optional
    automatic temperature control (ATC) display head.
    The (BCM) is operational when battery power is
    supplied to the module, ignition switch power is
    needed for ignition switched functions.
    The body control module provides the following
    features:
    Automatic headlamp and fog lamp
    A/C switch status/evaporator temperature status
    BCM diagnostic support
    Central lock and unlock (VTSS only)
    Climate Control (Automatic and Manual) system support
    Door ajar switch status
    Door Lock Inhibit (key in ignition or headlamps/park lamps on)
    Electronic Odometer Support
    Fog Lamp Control
    Headlamp multiplexing control
    Headlamp, Park & tail lamps with battery save feature
    Headlamp Time Delay
    Illuminated Entry with “fade to off”
    Interior lighting with battery save feature
    Mechanical Instrument Cluster (fuel level, dim data, odometer & warning chime) support
    Memory system (LHS and 300M)
    Overhead travel information system
    Power door lock multiplexing control
    Rear Window Defogger Control
    Remote Keyless Entry with Panic Mode
    Remote power deck lid release
    Rolling door lock control (customer programmable)
    Sentry key immobilizer
    Speed proportional steering
    Vehicle Theft Security System
    Wiper Control (speed sensitive with return to park)
    The BCM receives information over the PCI Bus
    from the PCM in order to support certain features.
    The required information is as follows:
    ² Engine RPM
    ² Engine Temperature
    ² Injector on Time and Distance Pulses
    ² Vehicle Speed
    ² Charging System Failure, Engine Temperature Limp-In, VTSS Arming Status
    ² Engine Model
    ² “Check Engine” lamp status
    The BCM provides the PCM with information on
    the A/C switch status, battery temperature which is
    determined by the ambient temperature sensor and
    the “OK to Start” or VTSS status.
    If the BCM is replaced, the VTSS must be enabled in the new BCM via the DRB lll®, in order to start the vehicle.

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    frosty, August 31, 2010, 21:42
     Rookie

    Thanks. I have had a mechanic trying to tell me the ingnition switch (electrical parts) is bad. I have more symptoms than the position on the switch is identified with.

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  • Answer #2

    Visitor, November 16, 2010, 08:27

    You're talking about the car's computer module or brain. What you've been told is true. If the computer is going bad, it must be replaced with a new one, a used one will not work. This happened to my car and my mechanic couldn't fix it; I had to take it to the dealer. They have to reprogram the new computer to match all the information in your old computer. This repair runs around $750 where I am from.

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