service throttle soon light

[82beast]

This problem is in my parents truck a 1996 GMC K1500HD 6.5TD suburban with 76000 miles. Around a week ago the sts light (service throttle soon) will turn on at random intervals and stay for about 1 maybe, I do mean maybe, 2 minutes. Then it might not turn on for a day or two. Do this leave a code in the computer and more importantly what part of the throttle needs to be serviced and does the dealer have to do it or can it be done in the driveway?
Thanks in advance for any help.

[Bobbie Martin]

The APP has three independent (triple redundant) sensors in it. If one is out, the truck will operate normally (no lights) but will store a DTC. If two go out, it will signal the STS light and operate at reduced throttle. All three out and it will only idle. It should have a DTC code if the STS light came on. If you can get the code(s), I may be able to point you in the right direction.

[whatnot]

Is the APP fixable or does it need to be replaced? The last time I had the scan tool plugged into my truck, it had a code for an APP error. (I think it was #3 but don't remember the code number)
I checked my brother's truck and the voltage reading was about the same as mine for all three so I just forgot about it.

[vernon morgan]

I had this same problem on one of my 1994 GMC trucks. It turned out that every now and then the battery cables would work slightly loose. A good cleaning of the terminals and a retighten fixed it.