Maybe this has been covered. Maybe it hasn't. I posted this on a few facebook groups now and people seem quite interested and several said I should share the writeup here. I was never able to find any of this info fully fleshed out or confirmed. Also lots of people saying it just wouldnt work. Im not even sure if im posting this in the correct section or if it should go in writeups. I guess ill let the mods and members decide.

This is how I have successfully ran 4 bolt / 6 wire / 90mm Drive by wire throttle bodies on numerous 03-07 customer trucks and many swaps without using an X-link adapter. INCLUDING the hall effect sensor aftermarket throttlebodies that dont play nice with xlinks. I am currently running this setup on my procharged 2004 yukon denali with a dorman ls2 hall effect throttlebody.

Also to be clear. I have no ill will towards the people that make the x-link or D2A module. Its a tough problem electrically to deal with and they do everything they can to deal with it. Iv had customers show up and have zero problems with their adapters. But I have also had very strange tuning problems from them as well as customers who had to carry code scanners with them to clear electrical dbw fault codes on occasion.

EDIT. Note. I have continued to add more info to this but have ran out of space. Most up to date info at this link where I added a troubleshooting section. Ill post updates in the comments.

https://intperform.com/how-to-upgrad...-truck-or-suv/

The writeup begins.

If you have this 03-07 gm truck throttlebody with 8 wires coming from the plug currently the norm is to run an X-Link adapter or computerized conversion module to convert from the strange 8 wire setup gm ran on 03-06 / 07 vehicles. While innovative it tends to be incredibly picky and cause serious tuning problems. Many people with this style of adapter tend to carry a code reader with them to clear codes just in case it goes into limp mode.



The core of this problem comes down to this. 99% of DBW throttlebodies on the market have two TPS sensors in them. One starts at 100% and drops to 0% at wide open. The other tps starts at 0% and rises to 100% at wide open. This is for safety so any electrical fault will not result in the throttle doing anything unpredictable. Around 2003 GM switched to a new unique style that had one tps sensor that went 0% to 100% but the 2nd tps went from 20% to 80%. This resulted in a LOT of problems and they switched back on the 2007+ trucks to a “normal” setup. This signal is also VERY difficult to electrically convert to any other style which is why the adapters have so many problems. Even worse it means there are exactly 0 plug and play upgraded throttlebodies on the market except a single bbk model that only is a couple mm larger than the stock 75mm unit.

How do we fix it the right way?

Its quite simple really. Gm likes to reuse everything and the 00-02 Traction control trucks had a dbw system that was almost the same as the C5 corvette, 04 gto, and 04 ctsv systems. This was originally tested on a 2004 GMC Yukon Denali with both the 6.0l and 5.3l pcm calibrations on the P59 “Blue Green” computer. Both resulted in no errors.

A disclaimer.

1. These systems are PICKY. I was able to successfully run numerous throttlebodies using this method but it doesnt mean the one you grabbed will work. I personally believe this method is far more tolerant than any other method but even I ran into junkyard throttlebodies with aftermarket tps resistors on them the refused to work. I have also had units that worked fine warm but would fault out when colder than 40f outside.
2. DBW throttle systems are a safety critical system. I make no guarentees as to the safety of any of this.

What materials do you need?

1. A 2000-2002 DBW Tac module from a truck that had traction control. While uncommon there were absolutely DBW trucks before 2003. I happened to snag part number 12574221 off of ebay.
2. A replacement 6 wire throttlebody. Ones confirmed to work will be listed at the end.
3. A 6 wire throttlebody pigtail. If you want to not cut the factory harness a female 8 pin connector can be used. The chinese clone X-Link modules are a great cheap source for both.
4. If you have a 2006-2007 truck you need to get a 03-05 pedal and harness. The 06+ pedal technically works but if you go past 80% throttle it faults out.


Step 1. Install the Tac module. Its 3 bolts to remove your old one. The new one should bolt in to the same place and both electrical connectors should plug in without problems. If you have a 2006-2007 truck this is also a great time to swap the pedal harness and the pedal.


Step 2. Rewire your throttlebody plug as shown below. I opted to buy an 8 pin extension to cut up instead of my factory harness but you can also just cut the plug off your factory harness. You'll notice that we are flipping the two tps signals. The traditional C5 throttlebody adapters flip the 5v and ground wires to accomplish this. But this is also why the hall effect units never work. I experimented quite a bit with flipping the tps, voltage reference, and the motor driver wires until I landed on this.



Step 3. Tuning.

1. In my experience I was able to plug in a ls3 gold blade throttlebody and a 07+ pickup throttlebody without any tuning. Technically speaking though for all throttlebodies you should update your “ETC Area Scalar”. There is a lot of arguing on this. GM makes the number larger for larger throttlebodies so I am of the opinion that it should be raised. 0.0330 works well for 90mm throttlebodies in my testing. This also would be a good time to revamp your shift points as a larger throttlebody changes your ideal shift points since the tps to airflow correlation is changed.

2. The LS3 gold blade is known to over rotate at wide open throttle. If you find your car goes into reduced power mode as soon as you floor it try lowering your max rotation to 96% instead of 100%. Silver blade throttlebodies are not known to have this issue. This is a known issue on the C5 but I have not ran into this on the trucks.

3. There are numerous tables related to the throttlebody in the tune with warnings to not modify them. This is because if you go out of range of what gm deemed normal it will at best put you in reduced power mode and at worse could brick your pcm / tac module. These ranges are hard coded in the TAC module. That being said I have successfully changed these tables to match stock GM tunes that used this TAC module as well as stock 03+ 5.3 and 6.0l dbw truck tables without any issues. Logically if GM put out stock tunes with these values the TAC module should be ok with them. You’ll notice that 6.0 and 5.3 trucks had different “Desired throttle Area” tables but used the same TAC module part number. I simply opted to use the stock gm numbers from a 2004 5.3 since it was less touchy. At a minimum you need to copy these numbers from a DBW truck.

Step 4. Install your throttlebody and test for function. Enjoy.

Confirmed working throttlebodies as of posting this
1. 07+ gen 4 truck throttle-bodies (OEM only confirmed! Aftermarket tps sensor packs are hit or miss)
2. LS3 Gold blade (OEM only confirmed so far! Aftermarket tps sensor packs are hit or miss)
3. FAST 102mm FST-54104 4 bolt throttlebody works! (Even though it has hall effect sensors)
4. Dorman LS2 977-820 HALL EFFECT throttlebody WORKS as long as you follow my wiring diagram above.

 

Wow this is awesome if true!! I believe you that’s not what I’m saying lol

 

I promise its real lol. I can post a whole walkaround video of it working on my truck if that helps.

Here is a video of when I first got the LS3 TB working.
Here is a photo of my Dorman LS2 TB on my truck which has hall effect sensors which to my knowledge has never been supported by any X-Link and therefore any gmt800.

 

I am going to have to get one of those TAC modules then. I have toyed with the idea of switching to DBW for better OEM throttle bodies as I have heard the aftermarket DBCs are not that good. I have no experience with any though.

 

That’s cool. Nice write up.

 

I am currently running an X-Link and a gold blade LS3 TB on my 04 Sierra 1500, and it seems to be giving me more and more issues.

If I make the connector/adapter as outlined in this writeup, install the 12574221 TAC module, what do I need to do to the tune on my truck? I have swapped a 6.0/4l80 into it so it is not running the stock tune. Do I need to check into/change anything in my tune? Or can I swap the TAC module, wire the adapter harness, and send it?

Would love to get rid of the X-Link if possible, so I am really interested in this!

 

I ran a 90mm and then a 102mm TB on my 05. I am running the 02 TAC module and an old spear tech adapter that I got like in 2008. No issues. I went this route after I had an x link failure

 

you don’t need a tune if you are just switching the pigtail
if you are switching to a larger TB AND the pigtail you will want to tune for the larger TB to get all the benefits

 

This is spot on.

 

Ran out of room. Wrote some troubleshooting info down.

Troubleshooting info: I recommend just placing the throttlebody on top of the intake so you can see what it does when testing this from the drivers seat. Leave the stock throttlebody bolted up. Just plug the tac module and the new TB in. Do not attempt to start the truck! It could instantly go wide open throttle.
1. Normal operation. You should see the throttlebody snap closed and then open slightly on key on. No reduced engine power notice on the dash. Pressing the gas should result in it smoothly opening to 100% around the same time the pedal goes 100%. Your good to go if this happens.
2. Wired correctly but resistor pack is out of range. Self test will happen but then reduced engine power on the dash. If you clear the codes without cycling the key it will likely start working as noted above. When the tac module snaps closed its going out of range. Need to find another throttlebody. Otherwise everything else is correct.
3. Everything works but throttle-body over-rotates at wide open and goes into reduced engine power. You'll notice the TB blade goes full open but you can still press the pedal a bit further. See the tuning section above to slightly limit how far the throttlebody is is allowed to open. This was common on C5 corvettes. Have not seen this on truck modules yet. NOTE: 06-07 trucks will also do this no matter how far you limit the TB opening if you haven't swapped the pedal. Swap it.
4. TPS OR motor signals reversed. Will fail the self test and codes will instantly set after clearing and touching the gas. Codes will be for a tac performance error but no tps electrical codes. TAC sees the blade moving the wrong way. Check wiring. Allegedly there could be throttlebodies out there that need the TPS or motor control wires flipped from what I have documented. I have not seen it yet though.
5. TPS AND motor signals reversed. No codes or dash errors. Self test results in the throttle opening to 100% and staying there. After timeout period blade will relax to mostly closed position. Touching the gas pedal will cause it to go to wide open again and pressing the gas will cause it to close. Flip the TPS and Motor wires. VERY DANGEROUS.
6. Wired wrong. Lots of codes for TPS and Motor electrical faults. Remember that the diagram posted is showing the connector faces of the factory female VEHICLE HARNESS plugs. NOT THE THROTTLEBODY SIDE. If you are hacking up an 8 pin extension or Chinese x-link to make an adapter harness link I did be mindful that itll be reversed.