In programing a body control modual, how do I know when the bcm is in communication with the pcm. thanks

With all those codes, you need a good auto-electrician with a $5,000 pro grade scan tool computer. Most of this is Body Control Module issues.

U0141 Lost Communication With Body Control Module "A"

https://www.obd-codes.com > u0141
Code U0141 pertains to the BCM "A" or the wiring to the BCM from the engine control module (ECM). The code, depending on the year, make and model of the ...

U1403 - Implausible Fuel Level Signal Received - Engine ...https://www.engine-codes.com > u1403'What is U1403 code meaning? ... The Fuel Level Sensor signal is a direct input to the Body Control Module (BCM). The BCM transmits the fuel level message to the ...

U110C CHRYSLER Code - Lost Fuel Level Messagehttps://www.engine-codes.com > u110c_chrysler'What is U110C CHRYSLER code meaning? ... The Fuel Level Sensor signal is a direct input to the Body Control Module (BCM). The BCM transmits the fuel level ...

U110E CHRYSLER Code - Lost Ambient Temperature Messagehttps://www.engine-codes.com > u110e_chrysler'What is U110E CHRYSLER code meaning? ... The Ambient Temperature Sensor signal is a direct input to the Body Control Module (BCM). The BCM transmits the ambient ...

Code U0100 stands for Lost Communication with ECM/PCM. The powertrain control module (PCM) is the computer responsible for engine management. Like the other computers (known as modules) onboard your vehicle, the PCM communicates over a bus.U0100 - OBD II Trouble Code: Lost Communication with ECM ...

Could be bad ignition switch or some other type electrical problem . Knowing how this system works on your vehicle is the key . The ignition switch is a low voltage input to the BCM - body control module . Depending on key position the BCM knows what relays to energize and what messages to send over the GMLAN serial data net work , PCM - engine computer . Hooking up a factory or some other type professional scan tool to view ignition switch inputs to the BCM , an checking for BCM DTC'S - diagnostic trouble codes .

Circuit Description
Moving the ignition switch to the START position signals the body control module (BCM) through discrete inputs from the ignition transducer that engine crank has been requested. The BCM verifies that theft is not active and sends a serial data message to the engine control module (ECM)/powertrain control module (PCM) requesting engine start. The ECM/PCM receives a 12-volt signal from the park/neutral position (PNP) switch or clutch pedal start switch notifying that it is safe to start the engine. There is a splice on this circuit in the fuse block-underhood that supplies power for the starter relay coil. The starter relay coil control circuit is then grounded by the ECM/PCM closing the switch in the starter relay suppling 12 volts to the S-terminal of the starter. Ground is supplied through the engine block.


Plus you need to under stand what power modding is , because the BCM is the power mode master . This will sound funny to someone who does not know about automotive electronics .
Serial Data Gateway
The body control module (BCM) in this vehicle functions as a translator between the High and Low speed GMLAN busses. The 2 communication protocols use the BCM to translate communicated serial data messages between the control modules over the 2 serial data busses.
Power Mode Master
This vehicles body control module (BCM) functions as the power mode master (PMM). Refer to Power Mode Description and Operation for a complete description of power mode functions.

Power to many of this vehicle's circuits are controlled by the module that is designated the power mode master (PMM). This vehicle's PMM is the body control module (BCM). The PMM controls which power mode (Run, Accessory, Crank, Retained Accessory Power, or Off) is active.

On vehicles that have several control modules connected by serial data circuits, one module is the power mode master (PMM). On this vehicle, the PMM is the body control module (BCM). The PMM receives 3 discrete ignition switch signals to differentiate which power mode will be sent over the Serial Data circuits. The 3-wire Ignition Switch table below illustrates the state of these inputs in correspondence to the ignition switch position:
Relay Controlled Power Mode
The body control module (BCM) uses the discrete ignition switch inputs Off/Run/Crank, Accessory, and ignition 1, to distinguish the correct power mode. The ignition 1 circuit is also routed to the Run/Crank relay for relay controlled power feeds during the appropriate power mode. The BCM, after determining the desired power mode, will activate the appropriate relays for that power mode.

You need to know how this all works , BCM - body control module controls all main powers for the vehicle . Ignition switch is a low voltage input to the BCM . For what ever position you move ignition switch too ,the BCM energizes relays to supply battery voltage . The BCM is called PMM - power mode master , also sends messages over the GMLAN serial data network to other modules to request start an a power up message . These systems are not for an unqualified DIY'er to mess with . Complex electronics involved .

The body control system consists of the body control module (BCM), communications, and various input and outputs. Some inputs, outputs and messages require other modules to interact with the BCM. The BCM also has discrete input and output terminals to control the vehicle's body functions. The BCM is wired to the GMLAN high speed serial data buss and the GMLAN low speed serial data buss and acts as a gateway between them. If the BCM does not communicate the vehicle will not start due to the inability of the engine control module (ECM)/powertrain control module (PCM) and theft deterrent module (TDM) to communicate without the BCM providing the gateway function.

Power Mode Master
This vehicles body control module (BCM) functions as the power mode master (PMM). The ignition switch is a low current switch with multiple discrete ignition switch signals to the PMM for determination the power mode that will be sent over the serial data circuits to the other modules that need this information, and so the PMM will activate relays and other direct outputs of the PMM as needed. Refer to Power Mode Description and Operation for a complete description of power mode functions.

Will not spin over ? When you turn the key to start ,the starter doesn't engage an spin the engine ? Dash light's come , headlamps come on bright ? Battery good , charged ? No codes ? just engine ,OBD 2 codes ? BCM codes ? How or what did you use to check codes ? code reader , scan tool ? A professional type that can read BCM - body control module codes ? Do you have any idea how complex the electronic's are on this vehicle ? Do you know what happen's when you turn the key to start ?

Power Mode Master
This vehicle body control module (BCM) functions as the power mode master (PMM). The ignition switch is a low current switch with multiple discrete ignition switch signals to the PMM for determination the power mode that will be sent over the serial data circuits to the other modules that need this information, and so the PMM will activate relays and other direct outputs of the PMM as needed. Refer to Power Mode Description and Operation for a complete description of power mode functions.

The body control system consists of the body control module (BCM), communications, and various input and outputs. Some inputs, outputs and messages require other modules to interact with the BCM. The BCM also has discrete input and output terminals to control the vehicle's body functions. Battery positive voltage is provided to the BCM from the BCM fuse in the underhood fuse block. The module has two grounds at G 202 as well as one directly to the vehicle battery. The BCM is wired to the GMLAN High speed serial data buss and the GMLAN Low speed serial data buss and acts as a gateway between them. If the BCM does not communicate the vehicle will not start due to the inability of the engine/powertrain control module (ECM/PCM) and vehicle theft deterrent (VTD) control module to communicate without the BCM providing the gateway function.

Gateway
The body control module (BCM) in this vehicle functions as a gateway or translator. The purpose of the gateway is to translate serial data messages between the GMLAN high speed buss and the GMLAN low speed buss for communication between the various modules. The gateway will interact with each network according to that network's transmission protocol.
One example of this necessary communication is the communication between the engine/powertrain control module (ECM/PCM) which is high speed serial data and vehicle theft deterrent (VTD) control module which is low speed serial data. If these modules can not exchange information, the vehicle will not start.
All communication between the BCM and a scan tool is on the High speed GMLAN serial data circuits. A lost communication DTC typically is set in modules other than the module with a communication failure.
If you don't know of any of this ,your best bet , take it to a qualified repair shop.

Best Manuals I don't know abut your model but i'm sure this lady here can help you

Cranks won't start , Did you check for spark ,fuel pressure ?
Radio Setup .Will the vehicle communicate with a scan tool ? Fuel an temp gauges not working are probably bad step motors inside the instrument cluster that controls the gauges . Where do the gauges read 0 or something else ?
Engine Coolant Temperature Gage
The IPC displays the engine coolant temperature as determined by the PCM. The body control module (BCM) receives a class 2 message from the PCM indicating the engine coolant temperature. The BCM converts the engine coolant temperature into a percent gage deflection. The IPC receives a message from the BCM via the serial peripheral interface (SPI) indicating the requested gage position. The engine coolant temperature gage defaults to 38°C (100°F) or below if:
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The PCM detects a malfunction in the engine coolant temperature sensor circuit.

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The BCM detects a loss of class 2 communications with the PCM.

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The IPC detects a loss of SPI communications with the BCM.

Fuel Gage
The IPC displays the fuel level as determined by the PCM. The body control module (BCM) receives a class 2 message from the PCM indicating the fuel level percent. The BCM converts the fuel level percent into a percent gage deflection. The IPC receives a message from the BCM via the serial peripheral interface (SPI) indicating the requested gage position. The fuel gage defaults to E (empty) if:
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The PCM detects a malfunction in the fuel level sensor circuit.

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The BCM detects a loss of class 2 communications with the PCM.

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The IPC detects a loss of SPI communications with the BCM.

When the fuel level is less than a pre-determined value, the low fuel indicator illuminates.
DTC P0462
The fuel level sensor changes resistance based on fuel level. The PCM monitors the signal circuit of the fuel level sensor in order to determine fuel level. When the fuel tank is full, the sensor resistance is high and the PCM senses a high signal voltage. When the fuel tank is empty, the sensor resistance is low and the PCM senses a low signal voltage. The PCM uses the signal circuit of the fuel level sensor in order to calculate the total remaining fuel in the tank. The PCM sends the fuel level percent via the class 2 serial data circuit to the body control module (BCM). The BCM converts this data and sends a fuel gage percent deflection to the IPC via the serial peripheral interface (SPI) in order to control the fuel gage. The fuel level information is also used for misfire and EVAP diagnostics.

Have
For the DE 100 series radio, complete the following procedure, using a scan tool, in order to properly set up communication:

1. At the Main Menu screen, select: Diagnostics.
2. At the Vehicle Identification screen, select the following options:
?€¢
Model Year



?€¢
Passenger Car


3. At the System Selection Menu screen, select: Body.
4. At the Vehicle Identification screen, select the Platform type.
5. At the Body screen, select: Radio.
6. At the Radio screen, select: Special Functions.
7. At the Special Functions screen, select: Radio Setup.
8. At the Radio Setup screen, press ENTER. The following test will set up a new or existing radio.
9. Select one of the following options:
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USA/Canada



?€¢
Export


10. Press the ENTER key.
11. Verify that the scan tool displays "Test in Progress."
12. Verify that the scan tool displays "Test Completed Successfully."
13. Press EXIT on the scan tool.

Important: The radio set up will configure the following systems:
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LEARN VIN

?€¢
Diagnostic Trouble Codes

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Class 2 Radio Messages

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Country Code

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Chime Volume

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Chime Level

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12/24 Hour Clock

Without learning the VIN, the radio will display a locked message (LOC).
The radio setup procedure will also clear the following messages:
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CAL

?€¢
CAL ERR

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CALIBRATE

I'm just curious if your aware of the BCM function's on your vehicle an if you know what the gate way module is ? An do you know about serial data communication between modules ? An do you know what the power mode master is ? And do you know the BCM needs programming ?
The body control module (BCM) in this vehicle functions as a gateway or translator. The purpose of the gateway is to translate serial data messages between the GMLAN high speed buss and the GMLAN low speed buss for communication between the various modules. The gateway will interact with each network according to that network's transmission protocol.
One example of this necessary communication is the communication between the engine control module (ECM)/powertrain control module (PCM) which is high speed serial data and Theft Deterrent Module which is low speed serial data. If these modules can not exchange information, the vehicle will not start.
Communication between the BCM and a scan tool can be on the high speed GMLAN network or low speed GMLAN network. If one network is lost, the BCM can still communicate with the scan tool. A lost communication DTC typically is set in modules other than the module with a communication failure.

Not for nonprofessionals! BCM communicates with PCM. Codes are set at at manufacturer for car vin and PCM it communicates with/ Any replacement requires programming via dealer or vehicle will not start.

What are you trying to do? If you are trying to replace a Body Control module be careful. It is linked very closely to your security system and will prevent your car from starting permanently. BCMs are programed and can't be changed. They have to communicate with the PCM to start the car. In most gm cars they are located behind the glove box.

What Dealership ?????? Saturn dealers are no more . What is it you would like to know ? Complex electronic's involved . Ignition switch is low voltage input to the BCM - body control module. Have seen this problem your having before , BCM problem ! Service engine light on ????? What DTC'S - diagnostic trouble code's are stored , same for air bags an Traction control "OFF" What code's . Any code's stored in any module ? Do a full vehicle scan .

The body control system consists of the body control module (BCM), communications, and various input and outputs. Some inputs, outputs and messages require other modules to interact with the BCM. The BCM also has discrete input and output terminals to control the vehicle body functions. The BCM is wired to the GMLAN High speed serial data buss and the GMLAN Low speed serial data buss and acts as a gateway between them. If the BCM does not communicate the vehicle will not start due to the inability of the engine/powertrain control module (ECM/PCM) and vehicle theft deterrent (VTD) control module to communicate without the BCM providing the gateway function.

Power Mode Master
This vehicles BCM functions as the power mode master (PMM). The ignition switch is a low current switch with multiple discrete ignition switch signals to the PMM for determination the power mode that will be sent over the serial data circuits to the other modules that need this information, and so the PMM will activate relays and other direct outputs of the PMM as needed. Refer to Power Mode Description and Operation for a complete description of power mode functions.

Your best bet , try a different dealer .