Body Control Module - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > Body Control Module

TJ Wrangler 4" Rough Country Suspension Lift Kits in JEEP Gear Change Packages From ROCKRIDGE 4WD. We Are DIFFIron Cross Customer JK and TJ Wrangler Bumpers now at ROCK

Reply
Unread 10-09-2004, 03:54 PM   #1
KeithH
Registered User
 
Join Date: Oct 2004
Location: Las Vegas, NV
Posts: 3
Body Control Module

I have a 2001 Grand Cherokee Limited, V8, alltime 4WD, 35,000 miles. For the second time in 15 months the body control module has gone out (first time at 20,000 miles). My Jeep dealer here in Las Vegas is trying to tell me I am the only one having this problem. The BCM is not covered under the extended warranty which makes me suspicious as to the frequency of their going out however my dealer is covering the replacment under Chrysler's warranty due to the period of time since they replaced the last BCM.

Anyone else having this problem with the BCM? Anyone with any ideas as to why mine may be going out so quickly. the Jeep dealer doesn't offer any clues.

Thanks.

KeithH in Las Vegas.

KeithH is offline   Reply With Quote Quick reply to this message
Unread 10-09-2004, 04:09 PM   #2
Meerkat
Registered User
1996 ZJ 
 
Join Date: Apr 2003
Location: Belle, WV
Posts: 4,930
I have had no problems with mine. It would help to know what kind of failure your BCM is suffering.

Here is a functional description of the BCM:

These vehicles use a body controller to control many of the body systems that previously used stand alone modules. There is only one "level" of Body Control Module (BCM) available as opposed to other vehicle lines that use a base or premium controller. To send and receive information the modules utilize the CCD bus currently used on other Chrysler vehicles. The bus is supplied bias or power from three different modules. The BCM and both the driver's door (DDM) and the passenger's door (PDM) modules can provide bus bias. Normally, the door modules only provide bias until their message has been sent, if the BCM is in a "sleep" mode. After the BCM "wakes up", it takes over biasing the bus.

Termination is provided from two modules, the Powertrain Control Module (PCM) and the BCM. As in other systems, termination is used to control the voltage level of the bus. Termination resistors used in the PCM and BCM typically measure 120 ohms of resistance each. Most bus systems use two points of termination for a back up in case of failure of one of the modules. If there are two points of termination, then total resistance of the bus circuit would equal approximately 60 ohms . This measurement could be made at the DLC after the bus becomes inactive.

The body control module provides or supports the following features:


Intermittent Wipe control
Door, Hood, Liftgate, Rear Glass Ajar Status
Reading and Transmitting of External Temperature
A/C Select Switch Status
Chime
Courtesy Lamps (including halo) with time-out feature
Automatic Headlamp Control
Headlamp Time Delay
Automatic Funeral Mode (with automatic headlamp only)
Gulf Coast Country Overspeed Warning
Illuminated Entry
Instrument Panel Dimming
Vehicle Theft Security System with Panic Mode
Door Lock Inhibit (key in ignition or headlamps/parklamps on)
Electronic Odometer Support
Brake Pressure/Park Brake Switch diagnostics
High Beam Indicator
Seatbelt Reminder
Speed Sensitive Intermittent Wiper Control
Fog Lamp Control
Remote Radio Controls and Radio Support
Mechanical Instrument Cluster Support
BCM Diagnostic Support
VIC (vehicle information center) support
Liftgate Courtesy Lamp Disable
Rear Window Defogger Control
The BCM receives information over the CCD Bus from the PCM in order to support certain features. The required information is as follows:


Engine RPM
Injector on Time and Distance Pulses
Vehicle Speed
Engine and Battery Temperature
Charging System Failure, Engine Temperature Limp-In, VTSS Arming Status
Engine Model
"Check Engine" lamp status
The BCM provides the PCM with information on the A/C switch status and the `OK to Start' or VTSS status.

The BCM has several programmable features. These features are enabled and disabled by using the DRB. See the chart.

HTH
62487799.gif  
__________________
Warren
Black 1996 5.2L ZJ Limited
Meerkat is offline   Reply With Quote Quick reply to this message
Unread 10-10-2004, 01:37 AM   #3
KeithH
Registered User
 
Join Date: Oct 2004
Location: Las Vegas, NV
Posts: 3
Body control module failures

Warren

The body control module failure I experienced both times took out my A/C, info center, headlights, windows, wipers, moon roof. Dash lights, flashers, door locks, seats, brake lights all continued working.

KeithH
KeithH is offline   Reply With Quote Quick reply to this message
Unread 10-10-2004, 07:53 AM   #4
Meerkat
Registered User
1996 ZJ 
 
Join Date: Apr 2003
Location: Belle, WV
Posts: 4,930
Keith,
Just the fact the failure took out the same components both times tells me that there is something external to the BCM that is damaging those circuits.
How long is the BCM lasting before it has to be replaced?
Here is a block diagram of the BCM system. Take a look at it and see if you can find any commonality in the failures. In other words, when I look at it, I think that all the components you said quit working are carried on the white 'B' connector. If a point external to the BCM that is common to only those functions that failed can be identified, then we will be able to establish the true problem that is burning up your BCMs.

HTH
62488228.gif  
__________________
Warren
Black 1996 5.2L ZJ Limited
Meerkat is offline   Reply With Quote Quick reply to this message
Unread 10-10-2004, 11:19 PM   #5
KeithH
Registered User
 
Join Date: Oct 2004
Location: Las Vegas, NV
Posts: 3
Body Control Module

Warren,

25 months before replacing the 1st BCM and 16 months for the second. I will speak with my dealer more about the cause and effect Monday. Thanks for your input and diagram.

KeithH in Las Vegas
KeithH is offline   Reply With Quote Quick reply to this message
Unread 12-01-2011, 05:17 PM   #6
Green96
Registered User
 
Join Date: Dec 2011
Posts: 4
I am new to this so sorry if I an doing this wrong! What year is this diagram for? I have a96 that I think may have a bad bcm and ecm . Whats a shut down relay? And why the hell do jeeps have so many electrical issues? jeep dealerships should be notified!
Green96 is offline   Reply With Quote Quick reply to this message
Unread 12-01-2011, 08:11 PM   #7
KoreaZJ
Registered User
1994 ZJ 
 
Join Date: Aug 2011
Location: GANGNAM STYLE
Posts: 2,666
AUTOMATIC SHUT DOWN (ASD) RELAY
When the ignition switch is in either the START or RUN position, it connects circuit A1 from fuse 8 in the Power Distribution Center (PDC) to circuit A21. Circuit A21 powers circuit F99 through PDC fuse 18. Circuit F99 feeds the coil side of the Automatic Shut Down (ASD) relay. The Powertrain Control Module (PCM) provides ground for the relay on circuit K900. Circuit K900 connects to cavity C3 of the PCM. When the PCM grounds the ASD relay, contacts inside the relay close and connect circuit F5 from fuse 20 in the PDC to circuit A142. Circuit A142 splices to the generator field terminal, fuel injectors, ignition coil and the upstream and downstream heated oxygen sensors. Circuit A142 also connects to cavity C12 of the PCM.
KoreaZJ is offline   Reply With Quote Quick reply to this message
Unread 01-01-2012, 10:28 PM   #8
Green96
Registered User
 
Join Date: Dec 2011
Posts: 4
Can an bad ignition switch cause stalling?
Green96 is offline   Reply With Quote Quick reply to this message
Unread 01-28-2012, 02:34 PM   #9
Green96
Registered User
 
Join Date: Dec 2011
Posts: 4
I put a new ecm in and no more stalling. Still reading p0420 code, cadilis effecency code also dont have gage or window power although sometime turning on headlights turns on window n gag power
Green96 is offline   Reply With Quote Quick reply to this message
Unread 01-28-2012, 08:20 PM   #10
samsonitesamson
Registered User
1995 ZJ 
 
Join Date: Mar 2008
Location: Bellingham, Washington
Posts: 1,213
holy thread resurrection batman.
__________________
When thou walkest through the fire, thou shalt not be burned; neither shall the flame kindle upon thee ~ Isaiah 43:2 ~



Quote:
Originally Posted by Bnabb View Post
it bolted right up, except one bolt but i didn't need it anyway
samsonitesamson is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.