AIM Solo in a 991 GT3 - Forget about the OBDII Cable Connection
#17
Nordschleife Master
Peter, do we have confirmation that the CANbus protocol for the 991 ECU is compatible with the 991 GT3? That would mean that the ECU between a regular 911 and the GT3 are the same. This would be nice for the guys taking delivery now not having to wait until AiM cracks the GT3 ECU protocol.
#18
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Unlike the 997.2 GT3, which retained the Bosch ECU and an entirely different (older and more limited in channels and throughput) management CANBus from the street cars newer (many more channels, much quicker sample and refresh rate) Siemens 3.1 ECU, the ECU in the 991 shares the same basic protocol with its GT3 variant.
As in the past, the diagnostic plug connection is only for static tests and OBD-II testing requiring less info and supplied at a rate slower than needed for good analysis, whereas tapping into the vehicle engine management-instrument cluster CANBus provides more channels and supplied at a much faster refresh rate.
We'll see when Richard and/or Matt let me piggyback the AIM connection onto their twisted-pairs, but this has been tested and released by AIM.
As in the past, the diagnostic plug connection is only for static tests and OBD-II testing requiring less info and supplied at a rate slower than needed for good analysis, whereas tapping into the vehicle engine management-instrument cluster CANBus provides more channels and supplied at a much faster refresh rate.
We'll see when Richard and/or Matt let me piggyback the AIM connection onto their twisted-pairs, but this has been tested and released by AIM.
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#19
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Richard, Matt, et al,
It is ALWAYS possible to wire to the backside of the J1979 (OBD-II) connector with an unterminated CAN cable, use the 991_981 OBD-II protocol and run the lead behind the carpet out of your way.
You could make up and/or install a harness like Jerry's or unterminate your existing OBD-II plug, too. I think if you're going to go to that trouble, I'd rather get more and quicker sampled information just going to the CAN of the car.
After hundreds of CAN installs on 997.1 and 997.2 GT3 and GT3RS cars without trouble, it's not a hack to do the same to 991 and 991 GT3 cars...
It is ALWAYS possible to wire to the backside of the J1979 (OBD-II) connector with an unterminated CAN cable, use the 991_981 OBD-II protocol and run the lead behind the carpet out of your way.
You could make up and/or install a harness like Jerry's or unterminate your existing OBD-II plug, too. I think if you're going to go to that trouble, I'd rather get more and quicker sampled information just going to the CAN of the car.
After hundreds of CAN installs on 997.1 and 997.2 GT3 and GT3RS cars without trouble, it's not a hack to do the same to 991 and 991 GT3 cars...
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M. Oldenslo (12-07-2019)
#20
Racer
Thread Starter
Just going to go with the CAN connection instead, be easier and safer than mucking about with the OBDII.
Do think the new OBD location means no data loggers will practically be able to connect using that port and will have to go via a splice into the CAN
Do think the new OBD location means no data loggers will practically be able to connect using that port and will have to go via a splice into the CAN
#21
Nordschleife Master
#22
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The Racelogic/VVBox is CAN-only anyway, IIRC.
#23
Rennlist Member
I'm asking because I just want to know that applying an electric soldering iron to the ECU wires doesn't introduce currents that can screw up the car's computers, electronics, etc.
If you solder the connections w/o issues, then that's good enough for me.
Thanks
#24
Nordschleife Master
Do you solder your connections? I'm asking because I just want to know that applying an electric soldering iron to the ECU wires doesn't introduce currents that can screw up the car's computers, electronics, etc. If you solder the connections w/o issues, then that's good enough for me. Thanks
#25
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I have always soldered the connections and never had an adverse event.
#27
Rennlist Member
OK, this seemed too easy.
My ECU wires in my 2011 C2S are supposed to be black/white and yellow/white twisted pairs. Trouble is, I found TWO twisted pairs of those color wires in the same wire harness bundle. They look identical.
Any ideas, anybody?
My ECU wires in my 2011 C2S are supposed to be black/white and yellow/white twisted pairs. Trouble is, I found TWO twisted pairs of those color wires in the same wire harness bundle. They look identical.
Any ideas, anybody?
#28
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Hmmm. I remember only one. Post a pic, but the twisted pair you want goes from the ECU to the back of the instrument cluster. I use the area next to the fuse box to access the harness. Will post pics later today.
#29
Rennlist Member
I'll take a picture and email it to you.
I hate to admit it, but I do not know how to attach a picture in a post.
I'm kind of thinking the two twisted pairs are actually the same pair. They just made a loop or something. They are identical.
Thanks for your response.
I hate to admit it, but I do not know how to attach a picture in a post.
I'm kind of thinking the two twisted pairs are actually the same pair. They just made a loop or something. They are identical.
Thanks for your response.
#30
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No sweat. Glad to help in any way. These things are GREAT tools!