TCU Power

gmcclintock · 06-23-2020, 02:55 PM

Hi everyone I've been working a retrofit and can't seem to get my USB working, so I began troubleshooting the MOST Bus and then power to the different modules when I discovered no power coming in to the TCU from the 54pin connector first of all I don't know if I'm sure which pin it is but I'm thinking it's pin 17. I have no power there at all, I checked the fuse box fuses 17, 26, and 27 and they are good to go 17 and 26 were empty (guessing because this car was not originally equipped with a TCU) so I populated them with the correct fuse and still no power to the TCU.

Can anyone help me with this? I would really appreciate it.

ctuna · 06-23-2020, 04:12 PM

If the car did not have a TCU to begin with they don't
include the fuse for it. The space will be empty on the fuse
board in the cabin.

Also fuse positions may vary by model year.
You need the shop manual to see the positions by year .
or you might try this
https://www.newtis.info/tisv2/a/en/
Hardware help for 7 series will be limited here.
If you find the hot line in the TCU connector you may want
to ohm it out to the fuse board.

gmcclintock · 06-24-2020, 05:24 AM

Quote:

Originally Posted by ctuna

If the car did not have a TCU to begin with they don't
include the fuse for it. The space will be empty on the fuse
board in the cabin.

Also fuse positions may vary by model year.
You need the shop manual to see the positions by year .
or you might try this
https://www.newtis.info/tisv2/a/en/
Hardware help for 7 series will be limited here.
If you find the hot line in the TCU connector you may want
to ohm it out to the fuse board.

Got it working by getting power to the unit on the red wire with green stripe according to the wire diagram on NewTIS. My fusebox diagram shows fuse 17, 26, and 27 are for phone which I assume its the TCU. and NewTIS show fuse 59 is where the Red wire with Green stripes connect to. Either way I got it connected there and by getting power there the MOST Bus signal was able to continue throughout the system which was the problem I was troubleshooting.

With that complete I'm on to try to code the MULF for USB functionality, another challenge I imagine.

Thanks

06-23-2020, 02:55 PM	#1
gmcclintock Private 0 Rep 66 Posts Drives: 2016 X5, 2009 328i, 2007 530i Join Date: May 2011 Location: Phenix City, Alabama iTrader: (0)	TCU Power Hi everyone I've been working a retrofit and can't seem to get my USB working, so I began troubleshooting the MOST Bus and then power to the different modules when I discovered no power coming in to the TCU from the 54pin connector first of all I don't know if I'm sure which pin it is but I'm thinking it's pin 17. I have no power there at all, I checked the fuse box fuses 17, 26, and 27 and they are good to go 17 and 26 were empty (guessing because this car was not originally equipped with a TCU) so I populated them with the correct fuse and still no power to the TCU. Can anyone help me with this? I would really appreciate it.
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06-23-2020, 04:12 PM	#2
ctuna Lieutenant General 1911 Rep 13,104 Posts Drives: 325xi 06 wagon MT Join Date: Jan 2010 Location: Santa Cruz, Ca iTrader: (0)	If the car did not have a TCU to begin with they don't include the fuse for it. The space will be empty on the fuse board in the cabin. Also fuse positions may vary by model year. You need the shop manual to see the positions by year . or you might try this https://www.newtis.info/tisv2/a/en/ Hardware help for 7 series will be limited here. If you find the hot line in the TCU connector you may want to ohm it out to the fuse board.
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