Where is bcm - LeSabre Buick Cars & Trucks

Holy Moly, lots of editing for clarity including a vehicle that doesn't exist :>D '98 olds slyatche'.


Take the Advice from Jeff Armer. He is _the_ Pro Expert here and has access for factory diagnostic flowcharts.
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BCM Identification
This vehicle is equipped with 1 of 3 types of BCMs. The BCM type installed on this vehicle is based on the vehicle equipment, point of sale, and option content.
Refer to On-Board Diagnostic Features for more information on how to identify the BCM type installed by using the on-board diagnostic feature. The following identifies the functions and basic option content of all 3 BCM types:
BCM Type 2
BCM type 2 is the base BCM that provides all standard BCM functions. Refer to the BCM function table for type 2 BCM.
BCM Type 3
BCM type 3 provides all of the features of the BCM type 2 plus keyless entry. Vehicles with RPO AU0 are equipped with a BCM type 3.
BCM Type 4
BCM type 4 provides all of the features of the BCM type 2 and type 3 plus content theft deterrent. Vehicles with RPO AU0 and UA6 are equipped with a BCM type 4.

On-Board Diagnostic Features
This vehicle is equipped with an on-board diagnostic feature capable of performing the following functions:
• Feature Customizing
• Displaying DTC codes
• Clearing DTC codes
• Input/Output Diagnostics
Feature Customizing Mode
The feature customizing mode is used to configure the BCM to function in various applications. The BCM can be customized to change the following vehicle functions:
• Interior Lighting Features
• Door Lock System
• Keyless Entry System
• Content Theft Deterrent System
In order to enter the feature customizing mode perform the following steps:
Turn the ignition switch to the LOCK position.
Remove the BCM PRGRM fuse.
Turn the ignition switch to the ACC position.
When entering the feature customizing mode, the BCM first identifies what type of BCM is installed on the vehicle by flashing the fasten seat belts indicator and sounds the chime 2, 3 or 4 times depending on the type of BCM used on the vehicle. There are 3 different types of BCM that can be installed on the vehicle based on the vehicle option content that matches the BCM capabilities. Ensure that the BCM installed on the vehicle is compatible with all of the features on the vehicle. Refer to Body Control System Description and Operation for BCM identification.
For more information on features that can be customized, refer to Personalization Description and Operation in Personalization.
Displaying DTC Codes
The DTC codes can be displayed by entering the diagnostics mode. Clearing DTC codes and Input/Output Diagnostics are also available in the diagnostics mode.
Complete the following steps in order to enter the diagnostics mode:
Turn the ignition switch to the LOCK position.
Remove the BCM PRGRM fuse.
Turn the ignition switch to the ACC position.
Quickly turn the ignition switch from the ACC position to the LOCK position then back to the ACC position within 1 second.
The BCM will enter the on-board diagnostic mode and flash the fasten seat belts indicator and sound the chime equal to the number of DTCs stored in the BCM memory. If no DTCs are stored, the BCM will not flash the fasten seat belts indicator or activate the chime.
The BCM flashes and sounds the first DTC with the lowest number, pauses, then continues with the next DTC until all of the DTCs are read. With a DTC 1, the BCM will only sound the chime once, and the fasten seat belts indicator may not flash. Once all of the DTCs are read, the BCM repeats this sequence 3 times.
Important: If the fasten seat belts indicator does not flash, and the chime does not sound, complete the following procedure in order to confirm that the BCM has entered the diagnostics mode:
Ensure that all of the vehicle doors are closed.
Open and close any vehicle door.
Fasten and release the driver seat belt.
The BCM sounds the chime when receiving an input signal such as Drivers door, Passengers door opening or turning on the courtesy lights when the BCM is in the diagnostics mode. Make sure these inputs are working correctly in order to prevent a false diagnoses.
If the BCM does not sound the chime upon opening a door or turning on the courtesy lights, repeat Step 1 of Entering the diagnostics mode. If the BCM does not enter the diagnostics mode, then refer to Cannot Enter BCM Diagnostics .
Clearing DTC Codes
After entering the diagnostics mode press and hold the Unlock switch for 4 seconds. The BCM will erase all history DTC codes. If a circuit is still shorted, the BCM will immediately store a history DTC code.
Input/Output Diagnostic Mode
After the BCM reads all of the DTCs in the memory, the BCM enters the Input/Output Diagnostic Mode.
The BCM flashes the fasten seat belts indicator and sounds the chime once when any of the following inputs are activated:
• Courtesy lamp switches
• Door lock cylinder switches
• Driver door ajar switch
• Headlamp switch
• IP compartment lamp switch
• Keyless entry request for door lock/unlock
• Keyless entry request for the alarm (RPO UA6)
• Passenger door ajar switch
• Power door lock switches
• Liftgate ajar switch
• Sliding door ajar switches
• Shock sensor
• Hazard switch
Perform the following procedure in order to test the BCM outputs:
Ensure that the BCM is in the diagnostic mode. Refer to Entering On-Board Diagnostic Mode.
Cycle the interior light switch ON then OFF.
The BCM will enter the Output Diagnostic Test Mode 1.
Each cycle of the interior light switch ON/OFF will select from following test modes depending on BCM type:
• Test Mode 1-- De-activates the courtesy lights output and removes power to all of the interior lamps.
• Test Mode 2-- Activates the courtesy lights output and provides power to all of the interior lamps. Interior lamp override switch must be ON.
• Test Mode 3-- Activates the courtesy lights output and turns ON all of the courtesy lamps. Interior lamp switch must be ON.
• Test Mode 4-- Activates the theft deterrent relay for 1 second and turns ON the headlamps. BCM type 4 only.
• Test Mode 5-- Energizes the horn relay for 25 ms. BCM type 4 only.
• Test Mode 6-- Turns on the security LED indicator. BCM type 4 only.
• Test Mode 7-- Turns off the security LED indicator. BCM type 4 only.
When the BCM completes all test modes, the BCM will repeat the test mode sequence.
Exiting Diagnostics
Perform the following procedure in order to exit the BCM diagnostics mode and return to normal BCM operation:
Turn the ignition switch to the LOCK position.
Reinstall the BCM PRGRM fuse.
Turn the ignition switch to the RUN position.
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Body Control Module (BCM)
Lower rear of the IP, on the heater



Removal Procedure
Important: The ignition switch should be in the OFF position when connecting or disconnecting the connectors to the BCM. Always disconnect the Brown BCM connector FIRST and connect the Brown BCM connector LAST. The BCM can set DTC(s) with the ignition switch in the OFF position.

Remove the left instrument panel sound insulator from the vehicle. Refer to Instrument Panel Insulator Panel Replacement - Left Side in Instrument Panel, Gauges and Console.
Remove the center instrument panel sound insulator from the vehicle. Refer to Closeout/Insulator Panel Replacement - Center in Instrument Panel, Gauges and Console.
Disconnect the electrical connectors from the body control module.
Bend the 2 snap retainers back slightly and pull the body control module from the bracket at an angle.

The body control module (BCM) must be programmed with the proper RPO configurations. The BCM stores the information regarding the vehicle options and if the BCM is not properly configured with the correct RPO codes the BCM will not control the features properly. Ensure that the following conditions exist in order to prepare for BCM programming:
• The battery is fully charged.
• The ignition switch is in the RUN position.
• The data link connector (DLC) is accessible.
Follow the instructions on the Techline Terminal and scan tool to program the BCM.
If the BCM fails to accept the program, perform the following steps:
• Inspect all BCM connections.
• Verify that the Techline Terminal and scan tool have the latest software version.

BCM Replacement
Replace the BCM only if diagnostics in this section directs you specifically to do so. Most system problems are traceable to faulty wiring, to connectors, or to components. The BCM itself is very reliable and is not likely the cause of a fault. Do not replace the BCM before performing a complete diagnosis or recurrence of the fault will likely occur. Note: Every input to the BCM is short to ground and short to battery protected. Every output from the BCM is short to ground and short to battery protected. Therefore, the BCM does not automatically need to be replaced when there is a short found in the wiring connected to it. Repair the wiring first, then check the system for any further problem.

BCM Programming
When a BCM is replaced, it must be programmed with the Vehicle Identification Number (VIN) of the vehicle that it is being installed in. The RadioTheftlock feature uses the VIN to verify that the radio has not been removed and improperly installed in another vehicle.
The programming of the BCM is accomplished by using a scan tool. The vehicles VIN is entered in the scan tool and then transmitted via a Class 2 physical message to the BCM. The BCM stores the VIN in EEPROM. The first communication between the BCM and radio re-arms the Radio Theftlock. To set up a new BCM, select SETUP NEW BCM from the BCM Special Functions menu and follow the instructions on the screen.

Body Control Module (BCM)
Mounted on the RH Kick Pad, behind the trim panel

Has to be programmed ,yes .
Body Control Module (BCM) Replacement
If the BCM is replaced, the following procedures must be performed in the subsequent order:
• BCM Reprogramming--Refer to Body Control Module (BCM) Programming/RPO Configuration in Computer/Integrating Systems for replacement, setup, and programming.
• Theft Learn--Refer to Programming Theft Deterrent System Components in Theft Deterrent.

A new body control module (BCM) must be programmed with the proper regular production option (RPO) configurations. The BCM stores the information regarding the vehicle options and if the BCM is not properly configured with the correct RPO codes, the BCM will not control all of the features properly. The Tech 2 software will automatically prompt you with the RPO available for the vehicle. Ensure that the following conditions exist in order to prepare for BCM programming:
• The battery is fully charged.
• The ignition switch is in the ON position.
• The data link connector (DLC) is accessible.
• All disconnected modules and devices are reconnected before programming.
To setup a new BCM, access the Vehicle Control Systems in Computer/Integrating Systems menu on the scan tool to program the BCM. Select Module Replacement/Setup and follow the instructions on the scan tool.
If the BCM fails to accept the program, perform the following steps:
• Inspect all BCM connections.
• Verify that the scan tool has the latest software version.

Gremlins ! No ! You want to know how this is possible ? The ignition switch is a low voltage input to the BCM - body control module ! Going by which position you have the key in ACCY , ON , run or start . The BCM system will control relays to turn on power to different parts of the vehicle ! The place to start would be to hook up a professional type scan tool that can communicate with the BCM . Could have U codes stored in one or more of the modules on the vehicle ! Do you know what a power mode master PPM is , BCM !
BCM Functions
The body control module (BCM) performs multiple body control functions. The BCM can control devices directly connected to its outputs based on input information. The BCM evaluates this information and controls certain body control systems by commanding outputs on or off. The BCM control inputs can be:
• Sensors and switches that are directly connected to the BCM
• Class 2 serial data received from other vehicle systems connected to the class 2 serial data link.
The BCM is also capable of controlling other vehicle systems that are not directly wired to the BCM. The BCM does this by sending specific messages on the class 2 serial data link. The system capable of performing the required function will respond to the BCM message.

Your best bet would be to take your vehicle to a Buick dealer !
Power Mode Master
This vehicles BCM fuctions as the Power Mode Master (PMM). Refer to Power Mode Description and Operation for a complete description of power mode functions.

Remove the radio bezel. Refer to Radio Replacement .
Disconnect the body control module (BCM) electrical harnesses.
Remove the BCM from the instrument panel (I/P) retainer:
3.1. Pry the BCM tabs from the locking tabs on the underside of the restraint.
3.2. Slide the BCM out of the retainer

The BCM needs to be programmed if replaced !
The body control module (BCM) must be programmed with the proper RPO configurations. The BCM stores the information regarding the vehicle options and if the BCM is not properly configured with the correct RPO codes, the BCM will not control all of the features properly. Ensure that the following conditions exist in order to prepare for BCM programming:
• The battery is fully charged.
• The ignition switch is in the ON position.
• The data link connector (DLC) is accessible.
• All disconnected modules and devices are reconnected before programming.
The following procedures need to be performed to properly configure a BCM:
BCM Programming
Passlock Learn
Program Key Fobs

Body Control Module (BCM)
In the center of the I/P, behind the HVAC control module

Replacing the BCM is easy , There are some steps that need to be followed but still easy ! After the new BCM is installed that's when the average person gets into trouble , because they don't have the knowledge ! They replace the BCM an it won't start an other thing's won't work . Replacing a BCM is best left to the dealer or some other qualified repair shop . It needs to be programmed an then Passlock Learn procedure has to be done. You may be replacing it when it doesn't need replacing . What problem is your vehicle having ? Have you had it checked for DTC'S - diagnostic trouble codes ? An not OBD2 codes , BCM codes won't turn on the check engine (MIL) light .
The body control module (BCM) must be programmed with the proper RPO configurations. The BCM stores the information regarding the vehicle options and if the BCM is not properly configured with the correct RPO codes the BCM will not control the features properly. Ensure that the following conditions exist in order to prepare for BCM programming:
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The battery is fully charged.

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The ignition switch is in the RUN position.

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The data link connector (DLC) is accessible.

Follow the instructions on the Techline Terminal and scan tool to program the BCM. If the BCM fails to accept the program, perform the following steps:
?€¢
Inspect all BCM connections.

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Verify that the Techline Terminal and scan tool have the latest software version.

Important: Perform new BCM setup when you replace Body Control Module (BCM). Refer to Body Control Module (BCM) Programming/RPO Configuration .
Disconnect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
Remove the left instrument panel insulator. Refer to Instrument Panel Insulator Replacement in Instrument Panel, Gauges and Console.
Disconnect the BCM electrical connectors.
Push the BCM up and move the bottom of the BCM away from and out of the mounting bracket slot in order to remove the BCM.
During Body Control Module (BCM) related service, the procedures below are designated to set-up the BCM correctly. Before you start, read these procedures carefully and completely.

Setup New Body Control Module (BCM)
Tools Required
Scan Tool (Tech 2) GM factory scan tool !
Important:
• Read this procedure carefully and completely.
• The BCM will not function properly if the Setup New BCM procedure is not performed.
• Perform the Theft Deterrent Re-learn procedure after successfully finishing the Setup New BCM procedure. If the Theft Deterrent Re-learn procedure is not performed after a BCM replacement, the following conditions may occur:
- The vehicle will not be protected against theft by the PASSLOCK system.
- The engine will not crank nor start. Your best bet is to take your vehicle to a dealer or a ASE certified repair shop who has proper tools .