2003 2500 silverado code P1516 TAC Module

[j cAT]

Originally Posted by 2eyefishclaw

Open the engine harness from the tac to the pcm using about 3-5 lbs of force tug on each of the tac wires you may find one or more wires broken inside of the insulation. The wires are all to small for the circuit.

If the TAC is causing reduced power it is usually the connector/pins corroded ...then its the intake manifold throttle body , that must be replaced on these 2003 models...this is because it is a total pkg......

your wire failures are interesting ... On these you have seen this ???

[rond201]

just replace the throttle body. my 2003 is fixed

[Miller74]

If this module goes unchecked or not repaired for an extended period of time could it cause the truck to go dead. The reason I ask is I parked it on sunday and went to start it on monday with no luck of it starting. After replacing the starter I noticed that it thinks it is in 2nd. gear, while actually in park. Local dealership says it is a trouble code to keep the truck from starting.

[cm1]

Hi and welcome
Yes this could lead to a no a start,the one I was working on would not start, but after having it towed to the shop it started right up.
When you say it didn't start what do you mean? It wouldn't crank or it wouldn't fire up?
Also it dose need to be fixed, because there will be a lose of power, and it could cause other problems.
Let us know what happens and how things turn out.

Good luck!!!!!!!

[Miller74]

OK a little history. I was top of my class in automotive and after high school was a tire / lube tech with the promis of advancement. Low and behold went a differant direction and became a machinest and CNC repair tech. Long story short I believe in fixing things, not find and replace.
So my reduced power engine light started becoming a habitual acurance for me and I took it to the local repair shop. They said to me it was trouble code P1516 and that I'd have to replace my Throttle Actuator Control Module. $376.50 plus labor. So being the guy I am I blew up at the poor gal who told me this news and asked if they beleived in actually fixing cars or just replacing parts. So dealing with about one hundred other proplems and wifes van. ( Hers gets fixed first ) I let the problem go on figuring I'd deal with it down the road. So when the truck would not start that Monday morning I did the tipical old school checks. 1st. Turned key to start. Got nothing. Checked battery. OK. So remembering the older starters, I repeatedly turned the key to the start position. Slow and rapid. When I did it rapidly I got a sound that reminded me of a engine that was vapor locked. Wanted to but couldn't. So based on the clicking and sounds it made and advice from some friends of mine I replaced the starter. Well that was a waste of $150.00 But seeing that my truck has 130,000 miles on it figured not a total loss. So here I am puzzeled I made a few more calls. My buddy has the code check and wouldn't be able to come till the fallowing day. I noticed at that point that the trucks gear position read out display that went real dim about three years ago was showing my the truck was in 2nd gear. After a call to the dealership they said it was a trouble code as well as my auto tech friend really! And after reading the post here I learned it could be a wire problem. I love wires. Never thought my truck would have more dang wires than one of my CNCs. So I started at the fuse box under the hood. And guess what I found At least 9 wires that the casing was rubbed off exposeing bear wires. After tugging and tapeing up all the exposed wires, I moved to the throttle body and tug tested all those wires. After tugging and taping went and tried starting the truck again. Nothing. The next dau my auto tech buddy came over with his computer and pluged it in. My truck spit out at least a dozen codes from transmission to other funky codes. He cleared out the codes and reset it. The truck started. He let it Idle for a couple minutes and shut it down then restarted it a couple of times and then rechecked it for trouble codes. All faults were gone. Conclusion. Bear wires in the bottom side of the fuse box may have been shorting out on them selfs. Do to years of driving ( since 03 ) vibrations caused exccesive rubbing and wear on wires exposing the copper strands causing shorts in the system. After wires were repaired and computer reset, I have not ( knock on wood ) had any problems.

[j cAT]

the location under the fuse box is where rodents may nest and chew wires...my 2000 silverado had this occur ....the wires need be coated with liquid tape...then they need loom covering the insulted wires to keep the rodents from damaging them again...

the TAC low power failure is a / was a very common failure ...OEM defect in 2003 ....................

[jreiter2]

I have similar problem with my 2003 silverado and would like to share my experiences. About two years ago I had one instance of the reduced engine power message and had to pull to the side of the road. While I don't remember the specifics I figured out that turning the ignition switch off and on several times cleared the problem. I had no other problems until last year when the same thing happened. Still didn't think much about it until now. Over the last two months I have had anywhere from one to three instances of the reduced engine power always in the morning when my lights were on. It never has happend any other time while driving...always in the morning with the lights on. About two weeks ago during the day my truck wouldn't start after driving it a couple miles and stopping to brwose for a few minutes at our local Home Depot. I went to leave the parking lot and the truck would not turn over. I jiggled the key switch, jiggled the gear selector to no avail. Finally when I turned the light switch from auto to manual lights on the truck started right up and hasn't happend since. So naturally I'm thinking my reduced engine power is related to the light switch in auto mode. Now when I go to work and it's dark I turn the switch to manual. For several days no problems then I got the problem with the lights in manual. I purchased a scanner and figured out that when this happens I get code P1516 (TAC). I have removed all connectors and used a good cleaner to clean all connectors. I've pulled on the TAC connector and wires while the engine was running and haven't seen the problem. Again I've only had this issue when the lights are on and am able to reset the code with the scanner. After reading all the other tips I plan to purchase the TAC and replace mine. Hopefully this fixes the problem.

[j cAT]

with your vehicle you will require the replacing of the throttle body. the TAC is a non removable part...If you can do this with out this throttle body replacement post back the part number and how you did it .

[jayeshseo]

Thanks for sharing your post with us.
I went through the whole bulletin and i found it as inspiration to me.
I felt aroung for some time that even I should have changed it instead of going to the dealers who only did what I did and charged an arm and a leg.

[jayeshseo]

Thanks for sharing your post with us.
I went through the whole bulletin and i found it as inspiration to me.
I felt aroung for some time that even I should have changed it instead of going to the dealers who only did what I did and charged an arm and a leg.

[jayeshseo]

Thanks for sharing your post with us.
I went through the whole bulletin and i found it as inspiration to me.
I felt aroung for some time that even I should have changed it instead of going to the dealers who only did what I did and charged an arm and a leg.

[kdmarb]

I was plagued by this problem for most of a year, mostly in cold weather but it would also sometimes occur in warm weather after I had been running for more than an hour. Engine would suddenly go to "Reduced Engine Power" and I would loose all power, pull off, shut down for 20 seconds and then restart again. Everything would then be fine. After taking it to the dealer for the third time, he replaced the entire throttle body as well as a post catalytic exhaust sensor. Now appears to be running fine.

291,000 miles and going strong.

[rpmferris]

Same problem with my03 6.0. Dealer re-pinned connector to throttle body. Found most of wires were just barely hanging on or the insulation was bad around wires. Ran fine for Day or so. Reduced engine power again. but only 1 code 1516. Going back into dealer going to check and clean grounds. Had DTC 0120,0220;1516;2135 before he re-pinned the connector. So helped a little bit i guess. Apparently low voltage to TAC module can trigger reduced engine power too. So good idea to check power supply (battery connections etc) + grounds.

[j cAT]

Originally Posted by rpmferris

Same problem with my03 6.0. Dealer re-pinned connector to throttle body. Found most of wires were just barely hanging on or the insulation was bad around wires. Ran fine for Day or so. Reduced engine power again. but only 1 code 1516. Going back into dealer going to check and clean grounds. Had DTC 0120,0220;1516;2135 before he re-pinned the connector. So helped a little bit i guess. Apparently low voltage to TAC module can trigger reduced engine power too. So good idea to check power supply (battery connections etc) + grounds.

tac failures 2003 are 110%...throttlebody needs replacing.

never use carb cleaner on this engine !

[rpmferris]

Throttle body was replaced. Just the other day. Same thing happened. So that wasn't it. Thankfully they took it back off and didn't charge me for it.