what does a BCM do?
03-31-2009, 06:33 PM
#1
Racer
Thread Starter
what does a BCM do?
I thought I had a bad turn signal bulb but once I replaced the bulb it didnt fix the problem so I talked to a guy at the dealership(I used to work there in sales) he said I need to replace the BCM. Well it seemed to be expensive for it to repair just a turm signal so I left it be. Now Im starting to have other electrical issues.1 is when I start the car it idles fine but when I start to move it dies just like the service colmn lock issue but no message comes up and I have the bypass. It may take 10 trys to get moving once I get going I can start and stop all day with no issues.Other times it will start up and go with no problems. 2 Now when driving sometimes the dash lights will flicker and once the car died while driving down the road. I checked the battery cables and everything is tight. I'm wondering if the BCM has something to do with this problem??
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Mo betta (08-06-2016)
03-31-2009, 06:48 PM
#2
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Check the codes on the car using the DIC. That will give you a lot of information and someplace to start from. Turn the ingition to on and then push and hold the options button followed by pushing the fuel button 4 times. The car will then enter diagnostic mode and you can let loose of the options button. The diagnostics will cycle through each subsystem on the car (including the BCM) and show all codes present in each subsystem. A code is an Alhpa character followed by four numerals and possibly followed by an H or C or both the H and C. Report them back here and somebody can help you then.
Bill
Bill
03-31-2009, 06:57 PM
#3
Le Mans Master
What type of column lock bypass do you have installed?
Is it the GM Harness K bypass or an aftermarket CLB?
Sounds like the BCM is doing what it is supposed to do, and the bypass relay has failed....
(Just curious, does your column still lock or has the lockplate been removed?)
Is it the GM Harness K bypass or an aftermarket CLB?
Sounds like the BCM is doing what it is supposed to do, and the bypass relay has failed....
(Just curious, does your column still lock or has the lockplate been removed?)
03-31-2009, 07:36 PM
#4
Racer
Thread Starter
I'm not with the car now so I can't pull codes. It's an aftermarket clb and have never had an issue for going on 3 years now asfar as pull key or any other messages they haven't came across the d I c since having the clb installed
04-01-2009, 01:32 AM
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St. Jude Donor '08
BCM = Body Control Module It controls or interfaces with ALL the body functions and communicates with ALL the other modules. Without it,,,your car will not function.
Yes,,,,reading the DTCs will help us help you figure out whats going on.
BC
Yes,,,,reading the DTCs will help us help you figure out whats going on.
BC
05-19-2009, 10:23 PM
#6
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what does bcm do?
Bill
Last edited by majbillgsd; 05-19-2009 at 10:26 PM.
08-09-2010, 11:22 AM
#7
Melting Slicks
Me too - sick BCM
Like some of the others.... after two dead batteries on my 2001 Coupe it was taken to the dealer on a flat bed truck. The BCM is drawing 4 amp and that is what is killing the batteries. The big unknown at the dealership is understand what circuit is shorted. Just replacing the expensive
(heard $1,000) BCM may not fix the problem. They are trying to find the bad circuit and this could be as expensive as the BCM.
This is not going to be an easy repair
(heard $1,000) BCM may not fix the problem. They are trying to find the bad circuit and this could be as expensive as the BCM.
This is not going to be an easy repair
Last edited by Arkay; 08-09-2010 at 11:28 AM.
08-09-2010, 12:55 PM
#8
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Dick
Im 99.1% that your BCM is NOT bad.
4 amp draw is NOT a short. When you say short, think of fire flames, burnt wires and components and smoke.
You just have something that is staying ON that should be OFF. If your STEALERSHIP cant find the issue in an hour,,,find a better service center!
Please call me. PM SENT. I hate stupid service centers!
NOTE! I tried to PM you but, theres not a PM available in your profile. I did leave something. It might be in your IMs
Bill C
Im 99.1% that your BCM is NOT bad.
4 amp draw is NOT a short. When you say short, think of fire flames, burnt wires and components and smoke.
You just have something that is staying ON that should be OFF. If your STEALERSHIP cant find the issue in an hour,,,find a better service center!
Please call me. PM SENT. I hate stupid service centers!
NOTE! I tried to PM you but, theres not a PM available in your profile. I did leave something. It might be in your IMs
Bill C
Last edited by Bill Curlee; 08-09-2010 at 01:06 PM.
08-10-2010, 03:25 PM
#9
Melting Slicks
On Monday the dealership called saying it could be the $1,000 BCM (Body Control Module) because the vehicle was drawing 6 amps with the key OFF. The tech was trying to find the short or whatever that killed two batteries. He was having to do it the old fashion way, one circuit at a time. The service writer called back at the end of the day saying the new battery was okay that it charged fine and the tech found the interior lamp ON so he turned it OFF. The excessive current draw stopped but he wanted to let it sleep over night in his stall and check it in the morning. They called Tuesday and I have the car back. For only $114 we went from Intensive Care to Release.
I have no idea how the interior lamps got turned ON but it was dying on me during the day and I probably never noticed the lamps staying on. The lamps turn ON when you open the door and they stay ON when you close it for about 30 seconds. The same set of lamps double as Map lights with two ON/OFF buttons in the mirror. I do not remember turning on a map light but may have done by accident the last time I washed the car and cleaned the mirror. The last wash was the morning before all this crap started.
Dodged an expensive bullet on this one. The real test will be to see if it starts after spending the night in our garage.
I have no idea how the interior lamps got turned ON but it was dying on me during the day and I probably never noticed the lamps staying on. The lamps turn ON when you open the door and they stay ON when you close it for about 30 seconds. The same set of lamps double as Map lights with two ON/OFF buttons in the mirror. I do not remember turning on a map light but may have done by accident the last time I washed the car and cleaned the mirror. The last wash was the morning before all this crap started.
Dodged an expensive bullet on this one. The real test will be to see if it starts after spending the night in our garage.
Last edited by Arkay; 08-10-2010 at 03:26 PM. Reason: typos
09-27-2010, 01:50 PM
#10
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On Monday the dealership called saying it could be the $1,000 BCM (Body Control Module) because the vehicle was drawing 6 amps with the key OFF. The tech was trying to find the short or whatever that killed two batteries. He was having to do it the old fashion way, one circuit at a time. The service writer called back at the end of the day saying the new battery was okay that it charged fine and the tech found the interior lamp ON so he turned it OFF. The excessive current draw stopped but he wanted to let it sleep over night in his stall and check it in the morning. They called Tuesday and I have the car back. For only $114 we went from Intensive Care to Release.
I have no idea how the interior lamps got turned ON but it was dying on me during the day and I probably never noticed the lamps staying on. The lamps turn ON when you open the door and they stay ON when you close it for about 30 seconds. The same set of lamps double as Map lights with two ON/OFF buttons in the mirror. I do not remember turning on a map light but may have done by accident the last time I washed the car and cleaned the mirror. The last wash was the morning before all this crap started.
Dodged an expensive bullet on this one. The real test will be to see if it starts after spending the night in our garage.
I have no idea how the interior lamps got turned ON but it was dying on me during the day and I probably never noticed the lamps staying on. The lamps turn ON when you open the door and they stay ON when you close it for about 30 seconds. The same set of lamps double as Map lights with two ON/OFF buttons in the mirror. I do not remember turning on a map light but may have done by accident the last time I washed the car and cleaned the mirror. The last wash was the morning before all this crap started.
Dodged an expensive bullet on this one. The real test will be to see if it starts after spending the night in our garage.
09-28-2010, 01:31 AM
#11
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St. Jude Donor '08
On Monday the dealership called saying it could be the $1,000 BCM (Body Control Module) because the vehicle was drawing 6 amps with the key OFF. The tech was trying to find the short or whatever that killed two batteries. He was having to do it the old fashion way, one circuit at a time. The service writer called back at the end of the day saying the new battery was okay that it charged fine and the tech found the interior lamp ON so he turned it OFF. The excessive current draw stopped but he wanted to let it sleep over night in his stall and check it in the morning. They called Tuesday and I have the car back. For only $114 we went from Intensive Care to Release.
I have no idea how the interior lamps got turned ON but it was dying on me during the day and I probably never noticed the lamps staying on. The lamps turn ON when you open the door and they stay ON when you close it for about 30 seconds. The same set of lamps double as Map lights with two ON/OFF buttons in the mirror. I do not remember turning on a map light but may have done by accident the last time I washed the car and cleaned the mirror. The last wash was the morning before all this crap started.
Dodged an expensive bullet on this one. The real test will be to see if it starts after spending the night in our garage.
I have no idea how the interior lamps got turned ON but it was dying on me during the day and I probably never noticed the lamps staying on. The lamps turn ON when you open the door and they stay ON when you close it for about 30 seconds. The same set of lamps double as Map lights with two ON/OFF buttons in the mirror. I do not remember turning on a map light but may have done by accident the last time I washed the car and cleaned the mirror. The last wash was the morning before all this crap started.
Dodged an expensive bullet on this one. The real test will be to see if it starts after spending the night in our garage.
Go buy TWO bottles of JACK DANIAL'S and Give ONE to the the technician and the other to the service manager. They are ON YOUR SIDE and " HONEST"!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!Tell them that they have my VOTE for the GOOD GUY award!
Bill Curlee
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09-28-2010, 07:56 AM
#12
Safety Car
map light? wow
everyone needs to take note of this because you would not see it on.
that's one of the few DEALERSHIPS I have heard of.
everyone needs to take note of this because you would not see it on.
that's one of the few DEALERSHIPS I have heard of.
09-28-2010, 10:55 AM
#13
Race Director
07-24-2015, 05:27 PM
#14
Advanced
BCM problem
My 2002 Z06 would not crank. It was like I was not pushing the clutch all the way to the floor. That was not it. Traced the problem “I think” to the BCM wasn’t sending a negative current to the Theft Deterrent Replay. So, I bypassed it and hard wired a ground wire in place of the YEL/BLK wire coming from the BCM. I have two questions: 1.Why is the BCM not sending the Negative signal? 2. What did I bypass?
07-24-2015, 07:52 PM
#15
Le Mans Master
Go buy TWO bottles of JACK DANIAL'S and Give ONE to the the technician and the other to the service manager. They are ON YOUR SIDE and " HONEST"!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!Tell them that they have my VOTE for the GOOD GUY award!
Bill Curlee
Bottle of Jack...$50 Fixed car...$114
Honest, ethical, smart, competent, techs... PRICELESS !!!!!
07-24-2015, 08:09 PM
#16
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St. Jude Donor '08
My 2002 Z06 would not crank. It was like I was not pushing the clutch all the way to the floor. That was not it. Traced the problem “I think” to the BCM wasn’t sending a negative current to the Theft Deterrent Replay. So, I bypassed it and hard wired a ground wire in place of the YEL/BLK wire coming from the BCM. I have two questions: 1.Why is the BCM not sending the Negative signal? 2. What did I bypass?
Here is the Theft Deterrent/CRANK circuit:
If you read the DTCs you will easily find what is causing the security issue:
READING YOUR Engine Diagnostic Codes
The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
NOTE! You can read the DTCs with the engine running and or driving down the road but it can distract you. BE careful! Some DTCs clear themselves when you turn the ignition OFF!
I always read my DTCs prior to turning OFF the ignition switch. If you have any messages on the DIC,, PRESS RESET until they are gone!
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open ect.)
3) Press and hold OPTIONS
4) While holding OPTIONS, press FUEL four times within a 10-second period.
Initially, on-board diagnostics go into an Automatic Mode which shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each. ( i.e. PCM = 4 codes) If none are present in a given module, you will see No More Codes on the display.
There are two kinds of diagnostic codes, Current and History designated with a letter suffix, "C" or "H". A current C code indicates a malfunction is present and active in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes.
More likely it's an indication of an intermittent malfunction.
Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module that does not operate with the key on and engine off, a special diagnostic tool called a Scan Tester is necessary to properly diagnose the malfunction.
Once the system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except English/Metric (E/M). Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present; press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press and hold the RESET button To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles.
Once you have the codes, the next question is: What to do with the information?
First, consult the factory service manual. Any serious C5 Do-It-Yourself owner should invest in the Corvette Service Manual of the appropriate model year. The Service Manual is really a requirement if you want to understand and work on your C5. You can GOOGLE the DTC and also find information on it.
Here is very good site that explains the DTCs:
http://www.corvette-web-central.com/C5DTCcode.html
http://www.obd-codes.com/trouble_cod...d-ii-codes.php
Make sure to include the H or C suffix!!
07-25-2015, 11:54 AM
#17
Advanced
Good stuff Bill, Ok, I reset all the codes before I bypassed the BCM the only code I received, was, 40-BCM B0432 H (Rear Defogger Relay Circuit). After the bypass was done, no code but the DIC showed “Service Steering Column” Any thoughts?
07-25-2015, 02:50 PM
#18
Burning Brakes
For the direct answer to the question, this is what the BCM does..
Originally Posted by GM
Body Control System Description and Operation
This vehicle is equipped with a Body Control Module (BCM) capable of performing multiple body control functions. The BCM, which is the power mode master, is responsible for sending the power mode messages on the serial data line to other systems.
Serial Data Power Mode
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 two signals/circuits from the ignition switch. These are the Ignition 1and Ignition 2 ignition switch signals/circuits.
To determine the correct power mode the PMM uses:
• The state of these signals/circuits, either switch closed (B+ = 1) or switch open (B+ = 0)
• The sequence of switch closures received by the PMM
• The status of the engine run flag
Fail-safe Operation
Since the operation of the vehicle systems depends on the power mode, there is a fail-safe plan in place should the PMM fail to send a power mode message. The fail-safe plan covers those modules using exclusively serial data control of power mode as well as those modules with discrete ignition signal inputs.
Serial Data Messages
The modules that depend exclusively on serial data messages for power modes stay in the state dictated by the last valid PMM message until they can check for the engine run flag status on the serial data circuits. If the PMM fails, the modules monitor the serial data circuit for the engine run flag serial data. If the engine run flag serial data is True, indicating that the engine is running, the modules fail-safe to "RUN". In this state the modules and their subsystems can support all operator requirements. If the engine run flag serial data is False, indicating that the engine is not running, the modules fail-safe to "OFF-AWAKE". In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
On this vehicle the following modules receive Serial Data Messages for power mode status:
• Driver Door Module (DDM)
• Passenger Door Module (PDM)
• Radio
Discrete Ignition Signals
Those modules that have discrete ignition signal inputs also remain in the state dictated by the last valid PMM message received on the serial data circuits. They then check the state of their discrete ignition input to determine the current valid state. If the discrete ignition input is active, B+, the modules will fail-safe to the "RUN" power mode. If the discrete ignition input is not active, open or 0 voltage, the modules will fail-safe to "OFF-AWAKE". In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
BCM Wake-up/Sleep States
The BCM is able to control or perform all of the BCM functions in the wake-up state. The BCM enters the sleep state when active control or monitoring of system functions has stopped, and the BCM has become idle again. The BCM must detect certain wake-up inputs before entering the wake-up state. The BCM monitors for these inputs during the sleep state, where the BCM is able to detect switch transitions that cause the BCM to wake-up when activated or deactivated. Multiple switch inputs are needed in order to sense both the insertion of the ignition key and the power mode requested. This would allow the BCM to enter a sleep state when the key is IN or OUT of the ignition.
The BCM will enter a wake-up state if any of the following wake-up inputs are detected:
• Any activity on the serial data line
• Hatch ajar switch
• Hatch release switch
• Door ajar switch
• Key-in-ignition switch
• Monitored load relay
• Park/fog/headlamps are on
• The BCM experiences a battery disconnect and reconnect condition.
• The ignition is turned ON.
The BCM will enter a sleep state when all of the following conditions exist:
• No activity exists on the serial data line.
• The ignition switch is OFF.
• No outputs are commanded.
• No delay timers are actively counting.
• No wake-up inputs are present.
If all these conditions are met the BCM will enter a low power or sleep condition. This condition indicates that the BCM, which is the power mode master of the vehicle, has sent an OFF-ASLEEP message to the other systems on the serial data line.
Power Requirements
The BCM has two main power feeds (high and low current), and two main grounds. The low power feed (battery 1) is used to provide power for the BCMs logic and internal driver operation. The high power feed (battery 2) is used to provide power for systems that draw higher amounts of current (motors, lights, etc.). The BCM will operate properly with a system voltage of 9.0-16.0 volts. If system voltages exceed 16.0 volts the BCM will provide protection by disabling certain functions that may be damaged due to higher than normal system voltages.
Monitored Loads
In order to minimize any battery rundown, the BCM can detect if certain electrical loads have been left ON after the ignition is turned OFF and the driver has left the vehicle. When the BCM detects that the ignition has been cycled to the OFF position, the BCM immediately checks the status of the load monitor input. If the BCM detects that a load is present (grounded input), the BCM turns ON the load monitor relay for 15 minutes. If after 15 minutes the BCM still recognizes that a load is present, the BCM will turn OFF the relay, removing the battery voltage from the loads. The BCM continues to monitor this circuit for a switch transition. The BCM will again turn ON the relay for 15 minutes if a switch transition occurs.
Load Shed Control
The BCM can turn off the rear window defogger and heated outside mirror electrical loads when the vehicle is in a condition where these loads may discharge the battery. The BCM will also remove these loads when engine demands are greater.
Interior Lamp Over Voltage Protection
The BCM disables the interior lamp bulbs when the system voltage is above 18.0 volts in order to extend the bulb life.
Driver in Vehicle Detection
Using the ignition switch/door ajar inputs, the BCM can detect whether or not the driver has left the vehicle. If the ignition is turned to OFF with no door ajar status detected, the BCM assumes that the driver is in the vehicle. As soon as the BCM detects a door ajar, the BCM will assume the driver has left the vehicle. The BCM uses this information to determine the RAP status, then sends the status to the other systems also responsible for RAP functions.
BCM Fail-Soft Condition
If a particular BCM malfunction would result in unacceptable system operation, the BCM takes a fail-soft action in order to minimize the condition. A typical fail-soft action would be the substitution of a fixed input or output value when the BCM is unable to interpret data correctly.
This vehicle is equipped with a Body Control Module (BCM) capable of performing multiple body control functions. The BCM, which is the power mode master, is responsible for sending the power mode messages on the serial data line to other systems.
Serial Data Power Mode
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 two signals/circuits from the ignition switch. These are the Ignition 1and Ignition 2 ignition switch signals/circuits.
To determine the correct power mode the PMM uses:
• The state of these signals/circuits, either switch closed (B+ = 1) or switch open (B+ = 0)
• The sequence of switch closures received by the PMM
• The status of the engine run flag
Fail-safe Operation
Since the operation of the vehicle systems depends on the power mode, there is a fail-safe plan in place should the PMM fail to send a power mode message. The fail-safe plan covers those modules using exclusively serial data control of power mode as well as those modules with discrete ignition signal inputs.
Serial Data Messages
The modules that depend exclusively on serial data messages for power modes stay in the state dictated by the last valid PMM message until they can check for the engine run flag status on the serial data circuits. If the PMM fails, the modules monitor the serial data circuit for the engine run flag serial data. If the engine run flag serial data is True, indicating that the engine is running, the modules fail-safe to "RUN". In this state the modules and their subsystems can support all operator requirements. If the engine run flag serial data is False, indicating that the engine is not running, the modules fail-safe to "OFF-AWAKE". In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
On this vehicle the following modules receive Serial Data Messages for power mode status:
• Driver Door Module (DDM)
• Passenger Door Module (PDM)
• Radio
Discrete Ignition Signals
Those modules that have discrete ignition signal inputs also remain in the state dictated by the last valid PMM message received on the serial data circuits. They then check the state of their discrete ignition input to determine the current valid state. If the discrete ignition input is active, B+, the modules will fail-safe to the "RUN" power mode. If the discrete ignition input is not active, open or 0 voltage, the modules will fail-safe to "OFF-AWAKE". In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
BCM Wake-up/Sleep States
The BCM is able to control or perform all of the BCM functions in the wake-up state. The BCM enters the sleep state when active control or monitoring of system functions has stopped, and the BCM has become idle again. The BCM must detect certain wake-up inputs before entering the wake-up state. The BCM monitors for these inputs during the sleep state, where the BCM is able to detect switch transitions that cause the BCM to wake-up when activated or deactivated. Multiple switch inputs are needed in order to sense both the insertion of the ignition key and the power mode requested. This would allow the BCM to enter a sleep state when the key is IN or OUT of the ignition.
The BCM will enter a wake-up state if any of the following wake-up inputs are detected:
• Any activity on the serial data line
• Hatch ajar switch
• Hatch release switch
• Door ajar switch
• Key-in-ignition switch
• Monitored load relay
• Park/fog/headlamps are on
• The BCM experiences a battery disconnect and reconnect condition.
• The ignition is turned ON.
The BCM will enter a sleep state when all of the following conditions exist:
• No activity exists on the serial data line.
• The ignition switch is OFF.
• No outputs are commanded.
• No delay timers are actively counting.
• No wake-up inputs are present.
If all these conditions are met the BCM will enter a low power or sleep condition. This condition indicates that the BCM, which is the power mode master of the vehicle, has sent an OFF-ASLEEP message to the other systems on the serial data line.
Power Requirements
The BCM has two main power feeds (high and low current), and two main grounds. The low power feed (battery 1) is used to provide power for the BCMs logic and internal driver operation. The high power feed (battery 2) is used to provide power for systems that draw higher amounts of current (motors, lights, etc.). The BCM will operate properly with a system voltage of 9.0-16.0 volts. If system voltages exceed 16.0 volts the BCM will provide protection by disabling certain functions that may be damaged due to higher than normal system voltages.
Monitored Loads
In order to minimize any battery rundown, the BCM can detect if certain electrical loads have been left ON after the ignition is turned OFF and the driver has left the vehicle. When the BCM detects that the ignition has been cycled to the OFF position, the BCM immediately checks the status of the load monitor input. If the BCM detects that a load is present (grounded input), the BCM turns ON the load monitor relay for 15 minutes. If after 15 minutes the BCM still recognizes that a load is present, the BCM will turn OFF the relay, removing the battery voltage from the loads. The BCM continues to monitor this circuit for a switch transition. The BCM will again turn ON the relay for 15 minutes if a switch transition occurs.
Load Shed Control
The BCM can turn off the rear window defogger and heated outside mirror electrical loads when the vehicle is in a condition where these loads may discharge the battery. The BCM will also remove these loads when engine demands are greater.
Interior Lamp Over Voltage Protection
The BCM disables the interior lamp bulbs when the system voltage is above 18.0 volts in order to extend the bulb life.
Driver in Vehicle Detection
Using the ignition switch/door ajar inputs, the BCM can detect whether or not the driver has left the vehicle. If the ignition is turned to OFF with no door ajar status detected, the BCM assumes that the driver is in the vehicle. As soon as the BCM detects a door ajar, the BCM will assume the driver has left the vehicle. The BCM uses this information to determine the RAP status, then sends the status to the other systems also responsible for RAP functions.
BCM Fail-Soft Condition
If a particular BCM malfunction would result in unacceptable system operation, the BCM takes a fail-soft action in order to minimize the condition. A typical fail-soft action would be the substitution of a fixed input or output value when the BCM is unable to interpret data correctly.
Last edited by Cliff8928; 07-25-2015 at 02:54 PM.
08-24-2016, 12:23 PM
#19
Engine got wet, now corvette wont operate properly
Check the codes on the car using the DIC. That will give you a lot of information and someplace to start from. Turn the ingition to on and then push and hold the options button followed by pushing the fuel button 4 times. The car will then enter diagnostic mode and you can let loose of the options button. The diagnostics will cycle through each subsystem on the car (including the BCM) and show all codes present in each subsystem. A code is an Alhpa character followed by four numerals and possibly followed by an H or C or both the H and C. Report them back here and somebody can help you then.
Bill
Bill
I recently found out that washing the engine of my 2003 corvette was a very bad idea. Now the clock, interior lights stay on and the drivers side door ding when it is opened, but with out keys in the ignition. I have pulled and replaced a couple of the fuses for the BCM and the clock turned off and I was able to start the car, but after a short while the clock/radio stayed on again after I turned the engine off and opened the door. I ran through the diagnostics during this time when the issue wasn't present. I was able to catch some of theses codes. I was writing as fast I could.
10-PCM NO CODES
B0-RFA 1 CODE
28-TCS
40-BCM
58-SDM U1000H U1064H
60-IPC NO CODES
80-RADIO NO CODES
99-HVAC 3 CODES U1160H
A0-LDCM 6 CODES B2282H U1096H
A1-RDCM 4 CODES B2285H
A6-SCM 3 CODES U1255H
How could the water have triggered this problem?
This is all I can currently get since the issue is currently present. I will try to get more if the issue drops off. I have the battery charger on the battery now since these interior electronics are draining my battery.
Thanks,
Any help would be greatly appreciated.
Thanks,
Dick
08-24-2016, 01:06 PM
#20
Le Mans Master
I recently found out that washing the engine of my 2003 corvette was a very bad idea. Now the clock, interior lights stay on and the drivers side door ding when it is opened, but with out keys in the ignition. I have pulled and replaced a couple of the fuses for the BCM and the clock turned off and I was able to start the car, but after a short while the clock/radio stayed on again after I turned the engine off and opened the door. I ran through the diagnostics during this time when the issue wasn't present. I was able to catch some of theses codes. I was writing as fast I could.
10-PCM NO CODES
B0-RFA 1 CODE
28-TCS
40-BCM
58-SDM U1000H U1064H
60-IPC NO CODES
80-RADIO NO CODES
99-HVAC 3 CODES U1160H
A0-LDCM 6 CODES B2282H U1096H
A1-RDCM 4 CODES B2285H
A6-SCM 3 CODES U1255H
How could the water have triggered this problem?
This is all I can currently get since the issue is currently present. I will try to get more if the issue drops off. I have the battery charger on the battery now since these interior electronics are draining my battery.
Thanks,
Any help would be greatly appreciated.
Thanks,
Dick
10-PCM NO CODES
B0-RFA 1 CODE
28-TCS
40-BCM
58-SDM U1000H U1064H
60-IPC NO CODES
80-RADIO NO CODES
99-HVAC 3 CODES U1160H
A0-LDCM 6 CODES B2282H U1096H
A1-RDCM 4 CODES B2285H
A6-SCM 3 CODES U1255H
How could the water have triggered this problem?
This is all I can currently get since the issue is currently present. I will try to get more if the issue drops off. I have the battery charger on the battery now since these interior electronics are draining my battery.
Thanks,
Any help would be greatly appreciated.
Thanks,
Dick
Then CLEAR your codes... go for a short ride then Pull the codes again BEFORE you kill the car... post them here.
