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Discussion Starter #1
So I've finished a T56 Magnum XL swap/FBO/DOD delete for my 2009 G8 GT.

For some reason the ECU thinks it's going 158mph at all times and will not go over about 5500rpm. If I try it just looses power. I do get a speedometer reading from the ABS sensors though that matches GPS.

Any thoughts on how to remedy this issue?

Currently the transmission is only electronically connected from the VSS sensor to pins 71 and 72 on the ECU (OSS/output speed sensor hi/low) which still shows 158mph always on torque lite. I've tried attaching each wire to each pin with no difference in results.
 

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I see that all the data from the automatic transmission was sent out thru 4 high speed data wires to the BCM. "If" the manual trans does not have that function, how is the BCM coping with the lost info ? If the BCM is expecting info from those wires an finds nothing there, could it default into the condition you are getting. Do the digital an analog speed displayed values appear to be accurate when driving around ?
 

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Discussion Starter #3
I see that all the data from the automatic transmission was sent out thru 4 high speed data wires to the BCM. "If" the manual trans does not have that function, how is the BCM coping with the lost info ? If the BCM is expecting info from those wires an finds nothing there, could it default into the condition you are getting. Do the digital an analog speed displayed values appear to be accurate when driving around ?

You know I forgot that there's a digital display, I don't ever use it lol. I'll give it a look when I'm driving next.

Chris White tuned the BCM for the manual swap. What exactly that entails I'm not sure but I'll shoot him a copy of what you said to see if he knows anything about it.
 
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