BCM use with E38 PCM
Thread Starter
Launching!
Joined: Jul 2004
Posts: 223
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From: Potomac, MD
BCM use with E38 PCM I know there are a few threads on his topic, but wondering if anyone had actually done it..
I know is not necessary to run engine, but it would be cool to have cruise control, retained power, AC (with ac module), etc
thanks
I know is not necessary to run engine, but it would be cool to have cruise control, retained power, AC (with ac module), etc
thanks
TECH Regular
Joined: Jan 2004
Posts: 426
Likes: 4
From: Austin, TX
David,
I am going to do this as well on my latest project. I really want to have cruise control, as well as the driver information center. I am using the 6 speed auto, and it would be nice to have a gear indication. I used the Dakota digital display on my 65 Corvette, but the 6L80E is strictly a computer shifted trans, and the position of the arm does not indicate what gear it is in. The use of a BCM looks pretty straight forward, and I am just going to get the DIC and the BCM from the same G8 that I got the rest of the drivetrain out of.
I was looking at the sequence of operation and the pin-outs on the computers, and it looks like a no-brainer. I may even transplant the entire G8 instrument cluster into my 67 Chevelle Wagon.
Regards, John McGraw
I am going to do this as well on my latest project. I really want to have cruise control, as well as the driver information center. I am using the 6 speed auto, and it would be nice to have a gear indication. I used the Dakota digital display on my 65 Corvette, but the 6L80E is strictly a computer shifted trans, and the position of the arm does not indicate what gear it is in. The use of a BCM looks pretty straight forward, and I am just going to get the DIC and the BCM from the same G8 that I got the rest of the drivetrain out of.
I was looking at the sequence of operation and the pin-outs on the computers, and it looks like a no-brainer. I may even transplant the entire G8 instrument cluster into my 67 Chevelle Wagon.
Regards, John McGraw
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Joined: Apr 2008
Posts: 828
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David,
I am going to do this as well on my latest project. I really want to have cruise control, as well as the driver information center. I am using the 6 speed auto, and it would be nice to have a gear indication. I used the Dakota digital display on my 65 Corvette, but the 6L80E is strictly a computer shifted trans, and the position of the arm does not indicate what gear it is in. The use of a BCM looks pretty straight forward, and I am just going to get the DIC and the BCM from the same G8 that I got the rest of the drivetrain out of.
I was looking at the sequence of operation and the pin-outs on the computers, and it looks like a no-brainer. I may even transplant the entire G8 instrument cluster into my 67 Chevelle Wagon.
Regards, John McGraw
I am going to do this as well on my latest project. I really want to have cruise control, as well as the driver information center. I am using the 6 speed auto, and it would be nice to have a gear indication. I used the Dakota digital display on my 65 Corvette, but the 6L80E is strictly a computer shifted trans, and the position of the arm does not indicate what gear it is in. The use of a BCM looks pretty straight forward, and I am just going to get the DIC and the BCM from the same G8 that I got the rest of the drivetrain out of.
I was looking at the sequence of operation and the pin-outs on the computers, and it looks like a no-brainer. I may even transplant the entire G8 instrument cluster into my 67 Chevelle Wagon.
Regards, John McGraw
Even though it looks like it. 
Teching In
Joined: Nov 2008
Posts: 17
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Just installed the BCM on an 09' 5.3 E38 Jeep swap. Took a little thinking out but now I have 6 speed tap shift, cruise control, smart charging and shift interlock operating. No need for gauges since I am running the Jeep gauges.
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Thread Starter
Launching!
Joined: Jul 2004
Posts: 223
Likes: 0
From: Potomac, MD
Vegasrobbi, could you provide further details on how you accomplished this feat?
Did you use a tech 2.? Is it just a matter of wiring bcm to ECM and bcm to system modules?
Thanks
Dave
Did you use a tech 2.? Is it just a matter of wiring bcm to ECM and bcm to system modules?
Thanks
Dave
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Teching In
Joined: Nov 2008
Posts: 17
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Body Control Module -BCM
Follow the wiring diagram for power and grounds. Connect all grounds! There are power wires hot all the time, in accessory, run and crank.
There was one circuit which the BCM sends out a 5 volt signal through the ignition switch then back to the BCM. This circuit has a drop resistor in the crank position. I did not run it and it threw a B1440 power input mismatch. I simulated the circuit to make the code go away but my outputs worked without it.
I have a Mastertech which I monitored the power modes but a Snap On and others can also get the data.
Two important things to consider, at least in my case.
The GM LAN bus is like a chain. In my case it goes ECM-TCM-BCM-DLC-terminator resistor. Both ends of the chain needs the terminator resistor. There is one in the ECM and the other I added after the DLC.
I bypassed many modules like the fuel pump and transfer case modules. It threw several U1*** codes, communication codes between modules. I calibrated them out with EFI Live, but again, it worked with the codes.
Second, several inputs, like the cruise control switch and shifter button are fed 12 volts from the BCM, then pushing the buttons steps the voltage down through resistors and is fed back to the BCM. I purchased the factory switches to get it working. The GM service manual gives the resistor values and my next project will be to integrate the original Jeep switches.
It's sounds complicated, it's not. Factory cruise is great, worth the extra effort over a pedal puller or modifier.
Follow the wiring diagram for power and grounds. Connect all grounds! There are power wires hot all the time, in accessory, run and crank.
There was one circuit which the BCM sends out a 5 volt signal through the ignition switch then back to the BCM. This circuit has a drop resistor in the crank position. I did not run it and it threw a B1440 power input mismatch. I simulated the circuit to make the code go away but my outputs worked without it.
I have a Mastertech which I monitored the power modes but a Snap On and others can also get the data.
Two important things to consider, at least in my case.
The GM LAN bus is like a chain. In my case it goes ECM-TCM-BCM-DLC-terminator resistor. Both ends of the chain needs the terminator resistor. There is one in the ECM and the other I added after the DLC.
I bypassed many modules like the fuel pump and transfer case modules. It threw several U1*** codes, communication codes between modules. I calibrated them out with EFI Live, but again, it worked with the codes.
Second, several inputs, like the cruise control switch and shifter button are fed 12 volts from the BCM, then pushing the buttons steps the voltage down through resistors and is fed back to the BCM. I purchased the factory switches to get it working. The GM service manual gives the resistor values and my next project will be to integrate the original Jeep switches.
It's sounds complicated, it's not. Factory cruise is great, worth the extra effort over a pedal puller or modifier.
Body Control Module -BCM
Follow the wiring diagram for power and grounds. Connect all grounds! There are power wires hot all the time, in accessory, run and crank.
There was one circuit which the BCM sends out a 5 volt signal through the ignition switch then back to the BCM. This circuit has a drop resistor in the crank position. I did not run it and it threw a B1440 power input mismatch. I simulated the circuit to make the code go away but my outputs worked without it.
I have a Mastertech which I monitored the power modes but a Snap On and others can also get the data.
Two important things to consider, at least in my case.
The GM LAN bus is like a chain. In my case it goes ECM-TCM-BCM-DLC-terminator resistor. Both ends of the chain needs the terminator resistor. There is one in the ECM and the other I added after the DLC.
I bypassed many modules like the fuel pump and transfer case modules. It threw several U1*** codes, communication codes between modules. I calibrated them out with EFI Live, but again, it worked with the codes.
Second, several inputs, like the cruise control switch and shifter button are fed 12 volts from the BCM, then pushing the buttons steps the voltage down through resistors and is fed back to the BCM. I purchased the factory switches to get it working. The GM service manual gives the resistor values and my next project will be to integrate the original Jeep switches.
It's sounds complicated, it's not. Factory cruise is great, worth the extra effort over a pedal puller or modifier.
Follow the wiring diagram for power and grounds. Connect all grounds! There are power wires hot all the time, in accessory, run and crank.
There was one circuit which the BCM sends out a 5 volt signal through the ignition switch then back to the BCM. This circuit has a drop resistor in the crank position. I did not run it and it threw a B1440 power input mismatch. I simulated the circuit to make the code go away but my outputs worked without it.
I have a Mastertech which I monitored the power modes but a Snap On and others can also get the data.
Two important things to consider, at least in my case.
The GM LAN bus is like a chain. In my case it goes ECM-TCM-BCM-DLC-terminator resistor. Both ends of the chain needs the terminator resistor. There is one in the ECM and the other I added after the DLC.
I bypassed many modules like the fuel pump and transfer case modules. It threw several U1*** codes, communication codes between modules. I calibrated them out with EFI Live, but again, it worked with the codes.
Second, several inputs, like the cruise control switch and shifter button are fed 12 volts from the BCM, then pushing the buttons steps the voltage down through resistors and is fed back to the BCM. I purchased the factory switches to get it working. The GM service manual gives the resistor values and my next project will be to integrate the original Jeep switches.
It's sounds complicated, it's not. Factory cruise is great, worth the extra effort over a pedal puller or modifier.
Were you able to program out all of the communication errors? This has been my main concern. Hopefully i can remove them with hptuners
Teching In
Joined: Nov 2008
Posts: 17
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I was able to tune out all the U1** codes with EFI Live. I still have some BCM codes like ambient light sensor, tailgate switch...but they do not appear in the ECM or TCM or illuminate the CEL.
Teching In
Joined: Nov 2005
Posts: 12
Likes: 0
From: Plano,Tx
Hey Vegas questions???? :D Hey Vegas,
What and where do you find out the terminator resistor ranges? I am currently working on a 2008 ecm/trans harness and wiring it for standalone right now. I have the ecm hooked to tcm with factory length wires then it splits off the data lines to the formed bcm connector. Will i need to add terminator resistors at the data link connector?
I like you bcm idea. may give that some thought in the near future
Sean
What and where do you find out the terminator resistor ranges? I am currently working on a 2008 ecm/trans harness and wiring it for standalone right now. I have the ecm hooked to tcm with factory length wires then it splits off the data lines to the formed bcm connector. Will i need to add terminator resistors at the data link connector?
I like you bcm idea. may give that some thought in the near future
Sean
Teching In
Joined: Oct 2005
Posts: 11
Likes: 0
From: Atlanta, GA
What do I need to get from the donor vehicle to make cruise work? I plan to use my stock gauges and stock switchs with the voltage divider resitors mentioned by VegasRobbi. If I ask for the BCM and the pigtails from it will that be enough? Are there any harnesses I should ask for uncut? Where exactly is the BCM I should ask for on a 2007 silverado 2500?
Thanks for the help!
Mike
Thanks for the help!
Mike
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Joined: Apr 2008
Posts: 828
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From: Right here, right now!
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Joined: Apr 2008
Posts: 828
Likes: 12
From: Right here, right now!
