Recently I've had some issues with my truck going into reduced engine power mode. Knowing that I'm throwing up a code and wanting a tune asap, I borrowed my bud's EFI-Live Flash-Scan to data log to send off to BlackBear. Well pulled the code and got P1516 which seems to be the Throttle Actuator Control (TAC). I've checked my wires and they appear fine, but I figure I'll take it off and thoroughly check it as well as clean it. If this doesn't work, would the easy fix be to purchase a new throttle body?

I have my logs, but my file is 663 KB with the forum limit at 634 KB so if anyone can help me there as well. Thanks.

Josh

 

is the TB ported?

 

The truck is bone stock besides airraid jr with amsoil filter and bullet. I just was getting it all logged for my tune.

 

I was getting P1516, and it was a nightmare. Can you post your tune? One of my problems was that my TB was only opening to 98.4 and the PCM wanted 100%. Do you get a code with the engine off? Pull on the Brown and yellow wires by the TB. If you feel them stretch, they are broken inside. This is a fairly common problem.

 

i have a spare throttle body if you need it and will be in santa maria from wensday to saturday ...

 

Thanks man I appreciate it. I will certainly let you know.

My tune file is too big it states, anyway I can cut down on the timing of it to make it a smaller file? It shows absolute throttle position all the way at 100%. There is no check engine light on, but just one of those hidden codes. Only time check engine light came on was after reduced engine power came on. I reset the pcm since then though. I will check the wires, thanks man.

Josh

 

I checked the wires and everything seems okay :/ I have my cal-speed longtubes just sitting in my room so probably just going to start those. My bud with a 2500hd ccsb 6.0 said he gets that code every now and then. Just wiggles his tb wires and it tends to go away. Hopefully invest in a tbss intake and 90mm tb later on so should eliminate the issue. Any thoughts on that? Thanks guys.

Josh

 

The P1516 can be an illusive little bastard. I've seen it be caused by a bad throttle body as well as a bad ground. I've yet to see a TAC module actually go bad. First thing you need to do is reach back behind the engine and find the ground on the passengers side head and tug on it pretty hard. If there is any question at all redo that ground. I like to use 12 gauge wire and a good heavy eyelet, solder, heat shrink, dielectric grease it, and use a heat shrink butt connector and double the stock ground wire over so it fits the yellow butt connector. Its way overkill but it works well for me. There is one on the back of the drivers side head that needs to be checked as well. Its harder to get to but if there is any question redo it. Technically you can move the ground to any good ground location on the engine but I like to put them back where they were for the next poor bastard that might work on it. Then you will really want to tug on the wires going into the throttle body connector. They are prone to breaking, especially the yellow wire. If that checks out most likely its a bad throttle body. I have had to completely rewire two trucks between the TAC module and throttle body though. I was getting up to 1 volt of voltage drop on a couple different circuits. I made up a new harness to bypass the original wiring and all was well after that.

 

Thanks for the heads up, I'll definitely be checking some stuff out especially since I'll be doing longtubes tomorrow/Thursday. Would it be a bad time to pick up a tbss intake/tb to try out and see if the code disappears? Thanks.

Josh

 

I see the 1516 and 2135 codes all of the time at work.

There is a Bulletin to clean the throttle body and relearn the idle.

There is a Bulletin to replace the T/body connector

There is a Bulletin to reprogram the ECM.

There is a Bulletin to replace the TPS sensor cover.

I have seen all of these work to solve the code setting. Start with the easiest first.

Clean it up and disconnect the battery for a couple minutes, start the truck up and let it idle for like 10 mins. Then drive it and see if the code comes back on. It may take a couple days or longer to reset if it is intermittant like these codes usually are.

Then keep going down the list till one fixes it. Hope this helped a little bit but these codes really suck to chase down.