1125 code issue
 

Ive swapped an 05 5.3 into my '72. It has the dbw, and everything from the swap came from the exact same truck.
I am still getting issues about every 2-3 times I drive it it will throw and 1125 code. At that point it will go into limp home mode.

It drives great, until it throws that code.

Any ideas on what this could be? It has always seemed to do this, but is getting worse and worse.

Re: 1125 code issue
 

I checked the pin connector on d. and it is not getting the 5 volt reference to it. any ideas?

Re: 1125 code issue
 

Sounds to me like a wiring issue, you've probably got a broken wire in the insulation somewhere. I would do a continuity check on all the wires from the TAC to the pedal, from the TAc to the PCM and from the PCM to the throttle body. When you're doing this, wiggle the wires around to see if you get any change in continuity.

Re: 1125 code issue
 

Are there any wires you would check before others than?

Re: 1125 code issue
 

About 5 inches or so away from the throttle body, they're known for breaking there. Or maybe start with the wire on pin D that you said doesn't have the 5v reference.

Re: 1125 code issue
 

The purple and the yellow wires off the TB/DBW are the usually bastardo's. Tug and wiggle on them (not more than 3 times, otherwise your just playing with yourself).

Otherwise, if at any point you extended or shortened any of the wires on the TAC circuit (to pedal, tac, and tb)...check those splice points. The DBW stuff is fairly voltage sensitive, and large solder areas or weak connections can have large and unpredictable effects.

Here's the weird one; if for some freakish reason it only happens in a certain area or on a certain road...i can pretty much confirm that these DBW systems (or the ECM, I'm not sure) can actually be affected by mass radio interference. I'm well aware how tinfoil hat that sounds, but I've personally experienced and near proven it.