P59 PCM & GEN 4 Throttle Body

[samgm2]

I am stumped. I've tried everything and nothing I try seems to work. I have:

1. An after-market harness (C5)
2. A 6L Gen 3 Engine
3. A P59 PCM
4. A 2015 GEN 4 Intake and Throttle Body

I rewired the harness to a 6 Pin Throttle Body connector to my harness.
I tied the two grounds together
I tied the 5v references together
I connected motor drive wires to pins A and B of the 6-pin connector
The throttle plate moves when I turn the key (sounds normal).
I've swapped TPS1 and TPS2 (so that the voltages swap).
I also tried reversing the motor drive wires (it still moves but a bit less).

Everything seems to be correct...

Using a Tech 2,
I read TPS1 to be about 3.4V (falls as I open the throttle plate)
I read TPS2 to about 1.6V (increases as I open the throttle plate).
The two voltages add up to the reference voltage.

The foot pedal verifies correctly according to the Tech 2.
The TPS sensors DO NOT. Tech 2 says they disagree.

I tried connecting both TPS input lines to a single output (so that the voltage matches, but no joy).

Does anyone have any idea why this isn't working?

Thanks, in advance...

[samgm2]

The intake and throttle body came off a 2015 Silverado. I am starting to suspect that the throttle body is just incompatible.

[blindsquirrel]

TP1 and TP2 voltages often sweep different ranges and directions from one year to the next, TB swaps like this almost never work just by repinning. Supposedly there are adapter boxes but I wouldn't trust my life to an aftermarket magic gizmo manufacturer. ETC systems are complex and kinda inscrutable for a reason, they need to be, because they can kill you and others if they go wrong.

[samgm2]

I appreciate the insight and your concern but this is still a GM TB and I will assume well made. I don't mind complex.

I was actually hoping to get information from someone that has tried it. One thought is to map the voltage swing from an older TB and see what it produces. I saw a cable called an X-link. It is a bit pricey and I am unsure why it's so expensive. Probably a tiny micro that remaps voltages using a little DAC. I will look at that next and see what I come up with but any 1st hand knowledge from someone that has tried it would be helpful.

I've seen some YouTube videos where the voltage from both TPS sensors was the same and others where the TPS sensor voltages add up to the reference voltage. The odd thing is that when I connected both TPS sensor inputs on the PCM to a single (the low voltage TPS2 output from the TB), the result was a mismatch in spite of the fact that the TECH 2 reported identical voltages and positions from both sensor outputs. Maybe the code expects to see a difference that doesn't exceed a certain percentage and rejects the inputs if they are identical? Seems unlikely... Time to hook up an old TB and see what the difference is.

[STAGEUP]

I've done many C5 Corvettes with the gold blade throttle bodies, without issues. It's completely possible.

[blindsquirrel]

You know what, knock yourself out. Maybe you'll learn something along the way.