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Looking to see if someone can point me in the right direction. Ive searched everywhere for a solution, no luck.
I have 2011 TT427 CTS V Coupe. I am running a piggyback Holley HP ECM which controls fuel and spark and the stock ECM controls everything else to keep the gauges going. The motor combo makes 1300+ and is built for more. However with the 6L90 being iffy at 400whp less than that, never had a chance to put it on kill on the street or on the Dyno. Got tired of rebuilding the 6l90 and decided to go TH400. 1st impressions are positive, but haven’t put the screws to it yet. Can’t wait to get it dialed in.
Now comes the problem. Everything works but the speedo on the dash. I have made the appropriate changes in HPTuners and when logging I get a speed reading...just nothing on the dash. Anyone done a similar swap and have similar problem? If so, how did you fix? Any other work around available? Any help i s much appreciated. Thanks for looking!
The THM400 transmissions were never originally built for electronic speedometer...
I am assuming you have installed a VSS conversion of some-sort.
What are you using and how do you have it installed and configured?
setup is as explained...th400 swap and HPtuners cal adjustments. No VSS, as it was part of OEM trans/6L90. I am getting a speed signal thru wheel sensor which I can see in HPTUNERS . Just not getting anything on dash
The THM400 transmissions were never originally built for electronic speedometer...
I am assuming you have installed a VSS conversion of some-sort.
What are you using and how do you have it installed and configured?
I have 3 tailshaft/tailhousing/speed sensor combos out of th400's. All long tail 27 spline. (NOT th375...they got th375 cast right into the tail and had lighter clutch counts.)
I've saved a couple long tail 32 spline housings and plan to open up the reluctor ring and fit it to the 32 spline setup if the occasion arises where someone needs one.
Anywho, for OP...you're gonna need to go into a little more detail on how you've done your wiring changes for us to help.
I have 3 tailshaft/tailhousing/speed sensor combos out of th400's. All long tail 27 spline. (NOT th375...they got th375 cast right into the tail and had lighter clutch counts.)
I've saved a couple long tail 32 spline housings and plan to open up the reluctor ring and fit it to the 32 spline setup if the occasion arises where someone needs one.
Anywho, for OP...you're gonna need to go into a little more detail on how you've done your wiring changes for us to help.
No changes in wiring. Standard Reid Case 400 with no electrical connections. Just trying to figure out how to use already present wheel sensors to drive dash speedo? And if not, what are options to add VSS sensor hardware that feeds to dash.
No changes in wiring. Standard Reid Case 400 with no electrical connections. Just trying to figure out how to use already present wheel sensors to drive dash speedo? And if not, what are options to add VSS sensor hardware that feeds to dash.
I think what maroon monster meant is that the 6L80 trans probably had a VSS output and that is what drove the information to your speedo. Since you are using an ABS ring to get speed for HPT it could be assumed that you A: modified this wire to provide speed signal or B: using a different PID to get speed via HPT that does not give speed to the dash as well. Could be as simple as a different module handles dash speed vs. the module that gathers speed from the wheel.
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I have 3 tailshaft/tailhousing/speed sensor combos out of th400's. All long tail 27 spline. (NOT th375...they got th375 cast right into the tail and had lighter clutch counts.)
I've saved a couple long tail 32 spline housings and plan to open up the reluctor ring and fit it to the 32 spline setup if the occasion arises where someone needs one.
Going with a VSS would be a better configuration then using an ABS/ Wheel-Speed Sensor...
The VSS gives a more consistent reading over reading from one of the wheels (They are more often than not turning at different speeds and get jerked to near stopping on bad pot-holes and bumps).
I personally would by a cheap reproduction aluminum speedometer housing and gear-set for the THM400 tail-housing.
Buy one of those VSS adapter-units that threads-on to the speedometer housing.
Then get it configured in HPT.
Was there a solution for this? We have a similar setup with a 427LSX Twin turbo V with a 4L80 Pcm2000 module and we can’t seem to get the speedometer to work.
All wiring is connected and working properly. The MPH is working on a live labtop but the speedometer is not working.
I believe the issue with these is that the CTSV 6l90e communicates output speed data via CAN and that is likely where the dash gets its information from.
If anyone has a solution I'd be curious to learn here
When I did a TH400 swap in my G8 I swapped a setting in the HPT speedo tab to read the ABS sensor and the dash speedo worked. Granted that was a 6L80 vehicle with an E38 ECM but it worked with some tweaking.
I believe the issue with these is that the CTSV 6l90e communicates output speed data via CAN and that is likely where the dash gets its information from.
If anyone has a solution I'd be curious to learn here
I believe this is correct. I vaguely remember having this issue in a 2010 Camaro. Speed would show in HPT but not on the dash. I've intentionally tried to forgot that car and anything related to it.
V2 CTS V TH400 SWAP Help: No speedo 
