Code P1516: Confused On What The Actual Fix Is..

Truck is a 2003 1500HD 6.0L Motor: Saw quite a few posts, especially in the last few weeks, but figured id start another anyways. Last week driving to work my truck threw the P1516 code and went into "Reduced Engine Power" mode where it would only go about 10mph and idled extremely rough when sitting. WhenI got to work I cleared the code and reset the computer for good measure and I hadn't had a repeat until yesturday morning. So Tuesday morning it did the same thing then again today on the way to work and also on the way home this afternoon, each time I was able to reset the code while driving with my Scangauge and the truck continued to drive fine. So I got on here and did a search and found that it could either be the wiring into the sensor or the sensor itself. I checked the wiring as much as I could see and cleaned the plug, didn't really see any issues there. I don't have access to any good electical testers so I really am not able to test the wiring itself. My question basically is what actually gets replaced as far the sender goes, to me it looks like its part of the throttle body (looks to be riveted on) so was wondering if you order the sender what all is included and also how/where the best place to order the wiring if thats the fault. I really just want to know if anyone has had experience with this and which is more likely to be the issue. I really hate for this to happen sometime on the highway, doesn't seem to safe. Any help or comments would be greatly appreciated..Sorry for the long post!
Danny-

Looks like the one or both sensors, ( drive by wire? is it?) Check this link. http://service.gm.com/gmspo/mode6/pdf/2000/2000file16.pdf. A full scan will show what these are doing or not doing.

Looks like the one or both sensors, ( drive by wire? is it?) Check this link. http://service.gm.com/gmspo/mode6/pdf/2000/2000file16.pdf. A full scan will show what these are doing or not doing.

Thanks for the response and the link, very informative been trying to find a breakdown like that for quite a while now. To answer your question it is "drive by wire" system and from what I found on the internet this was the first year the Silverado had this and that the '03 models had a lot the same issues I'm describing. I did some more poking around on the internet and found many people that had issues with the plug going into the module and found that replacing this fixed their problem. So this evening I went out started the engine and let it warm to operating temp, popped the hood and shook each individual wire going into the module and sure the enough when I shook the brown one the truck went into "reduced engine power" and started to idle roughly, cleared the same code and idled perfectly again. I went ahead and orderd a new plug with pigtails and am going to try replacing the plug to see if it fixes my problem. I will keep everyone updated on the outcome. If anyone has anymore things to add or recommend please do. Thanks again

I did some more poking around on the internet and found many people that had issues with the plug going into the module and found that replacing this fixed their problem. So this evening I went out started the engine and let it warm to operating temp, popped the hood and shook each individual wire going into the module and sure the enough when I shook the brown one the truck went into "reduced engine power" and started to idle roughly, cleared the same code and idled perfectly again. I went ahead and orderd a new plug with pigtails and am going to try replacing the plug to see if it fixes my problem.
How is the fix working out?

Is it possible to post a picture of the location of the faulty plug and the module? I'm handy but I need a visual to help me locate these parts under the hood.

What is the part number of the new plug and pigtail? How much was it?

Many Thanks!

I had to replace my tps, the wire were good .When I removed it I found a small hole in the casting, I think this was letting moisture get in and disrupting the signals and throwing the codeI have the pics but it wont let me post them.

Did your problem got solved?

Well its been close to a month now since I replaced the harness and so far no repeats with the code being thrown or the truck going into "Limp Mode." Heres some info for Snosheriff hopefully this will help. I found two pictures for you, one of the engine bay with the plug I replaced circled and the second the picture of the actual plug. The Delco part number is PT1572 which I picked up from rockauto.com for about 90 bucks. The part comes with the plug and about 12" of wiring and luckly the break in my wires was about 8"in back from the plug. The wires that you recieve are all white so try not to get them mixed up if rewiring the plug, only 8 wires so it's not that tough. Here are the pictures you wanted, the first one is from a Silverado Hybrid but the plug is in the same location on all of them. If your standing in front of your truck it is located on the left side(pass side) pluging into the throttle body (some what covered by the Vortec Plastic Covering). Any other questions I will glad to try and help.


http://i171.photobucket.com/albums/u302/mcconnell2006/2009SilveradoHybridEngine.jpg

http://i171.photobucket.com/albums/u302/mcconnell2006/getimage.jpg

mcconnell45,

has your problem been solved? im have the same issue and im about $600 deep in trying to fix it...

mcconnell45,

I have a 2003 cadi escalade ext.

has your problem been solved? im have the same issue and im about $600 deep in trying to fix it... changed the TB and pedal sensors, had it "flashed" or reprogrammed at the dealership... still goes into the dreaded "reduced engine power" mode. any advice?

Well his last post was over 4 years ago. Anyway if you read thru his post you will see that apparently it has been fixed.

mcconnell45,

I have a 2003 cadi escalade ext.

has your problem been solved? im have the same issue and im about $600 deep in trying to fix it... changed the TB and pedal sensors, had it "flashed" or reprogrammed at the dealership... still goes into the dreaded "reduced engine power" mode. any advice?

If your caddy uses the same throttle body, then it is possible that you need a new one. these 2003 throttle body drive by wire types had 110% failure rate. don't know what you have in your vehicle . The connector that feeds the throttle body to the TAC is another defective design which should also be replaced when replacing the throttle body if there is any pin corrosion of any kind.

If your caddy uses the same throttle body, then it is possible that you need a new one. these 2003 throttle body drive by wire types had 110% failure rate. don't know what you have in your vehicle . The connector that feeds the throttle body to the TAC is another defective design which should also be replaced when replacing the throttle body if there is any pin corrosion of any kind.


Thanks Jcat,

I changed the TB with a new refurb, and this is when it all started. So i went to dealership to get the PCM flashed... still have the problem. what do you think i should do next, new pigtails at the TB and TAC module? also, ive noticed that the traction control kicks in (or turns off... the light for it comes on also with the check engine light, and the reduced engine mode kicks in)... all that happens at the same time.

Thanks Jcat,

I changed the TB with a new refurb, and this is when it all started. So i went to dealership to get the PCM flashed... still have the problem. what do you think i should do next, new pigtails at the TB and TAC module? also, ive noticed that the traction control kicks in (or turns off... the light for it comes on also with the check engine light, and the reduced engine mode kicks in)... all that happens at the same time.

my guess is you get what you pay for . buy a new unit. no such thing as new refurbished. all it takes is one miss on the resistance and you will loose power .

some had dealerships pull this trick , to make more money.

thanks again Jcat, that makes since... do you think i will have to get the PCM flashed again?