I've done a lot of reading on this and other forums and I thought I had the right parts but maybe not. Here is what I've got going on:

• 2002 Sierra Denali with LQ4
• Replaced intake with '07 NNBS intake using stock LQ4 injectors for now
• 8 pin to 6 pin wiring adapter
• AC Delco 12679524 NNBS 90mm truck throttle body

With this setup, on startup I get the "Reduced Engine Power" message and the throttle is non-responsive.

Here are the DTCs:

P0401 (I expect this because of the EGR delete)
P1120 TPS out of range
P1220 Throttle Control System Malfunction?
P1516 TAC module error ( from my research, I thought the 02 truck TAC module was compatible with the LS2/NNBS throttle bodies?)
P1518 another TAC module error?

I was originally going to use an LS3 TB with Torque Rush X-link but when I emailed the Torque Rush tech support they said that was not needed for my application and all I needed was an LS2 TB and a simple plug adaptor. I ordered an LS2 TB from Amazon Warehouse and what I received was a unit that had been ported by Vmax CNC. I was skeptical that it would even work as it was purchased by Vmax and returned to Amazon so I assumed it would have the common TPS error and it did along with three other DTCs.

I returned that LS2 TB and purchased 90mm truck throttle body because everything I read said the LS2 TB and 90mm truck TB were interchangeable. I just installed it and am getting the same error codes.

My questions are:

• Do I have the correct setup for my application or do I need an LS3 TB and X-link?
• If I do have the correct parts, do I just need a tune for it to work correctly (I assumed if the parts were correct I wouldn't get the REP code and that it may just run a little rough until a tune)
• Is it possible the plug adapter I purchased is faulty and causing these problems?

Any help would be greatly appreciated!

Thanks,

AJ

 

I see no mention of a tune.

If it hasn’t been tuned, it needs to be. Airflow model is off, ETC area scaler is off, injector data, etc etc etc.

 

I figured out that my problem was the adapter harness was not right for the conversion of an LS1 to LS2 style throttle body as the LS2 style opens in the opposite direction. I swapped the pins on the TAC connector and it works now up to about 5,800 RPM. At that point it throws the REP code which is what I would expect will be taken care of by a tune.

 

If your supercharger boosted you want it to open the opposite direction so it doesn't suck shut.

 

Good to know. Wish it was but unlikely that will happen. Thanks