OLDSMAN

My LS3 and Rostra Cruise Control are not behaving as they should. Originally installed about 3 years ago by my builder, the cruise worked fine, but recently the drive by wire throttle has stopped working randomly while driving the car. I have to come to a stop and restart the engine about 10 times for the ECM to conclude that the problem with the pedal correlation no longer exists and it is ok with allowing the pedal and throttle to operate again. The ground from the Rostra box was originally connected to the purple wire going to the pedal which is the sensor ground for one of the 3 wire circuits pedal circuits. I disconnected that and reconnected it to a good ground. Now the problem is worse and when I pressed the "set" button, the throttle immediately stopped functioning and code P2138 pops up again, but after clearing the code, the cruise worked again for a bit. The Rostra Cruise Module seems to be the smoking gun here. Dakota Digital sells, what looks to be the same module.

I did find the ewingr's Thread titled " P2138-LS3- Dakota Digital Cruise Control" from 12/ 2019 but saw no real conclusion. Should I try another new $500 unit?

Thanks All

OLDSMAN

I see that Speartech is offering their own cruise control for a drive by wire LS3. Has anybody tried one ? My builder used a harness by Current Performance with the stock ECM from the 2012 Camaro.

fbrown540

I have a Speartech LS3 harness with Cruise Control. Speartech supplies a Rosetta cruise control unit. My car ran maybe 5 miles before the P-2138 code occurred. Codes would occur randomly every few miles. I had to use a code reader to reset the code as my car stopped driving as soon as the code occurred, I ended up disconnecting the Rosetta unit and did not have any P-2138 codes. After that I only drove the car a few hundred miles, mostly to move it to my new home. The transmission died shortly after moving so I have not had a chance to do any troubleshooting. In my case this has stretched out over 5 years with the car only being drivable for 2 months.

OLDSMAN

The Speartech unit on the Speartech website looks nothing like the Rostra unit. (fbrown, I assume you mean Rostra and not Rosetta) I do see that the Dakota Digital unit is unmistakably a Rostra unit. Maybe asking Speartech for clarification would be a good idea. The search for a solution goes on.