Pcm/harness compatibility l83?

[msbweiland]

Have some newbie questions. Got a supposedly 2017 Silverado 2wd l83 from a vender for a chevelle swap. Came with a 6l80e. First red flag was when he sent a 4wd harness instead of a 2wd.
Got it running and I am having issues with some codes. One of which is the hp fuel not getting a signal. I checked the blue connector x1 and there?s no blue white on pin #41 ( I think) where it should be. None of the hp sender wires go to the connector either. My tracer is telling me it goes to x2 like an earlier l83. I?ll check for continuity tonight.
Can I flash pcm to an earlier vin/os? Or is it easier to change the pcm or harness?
Anyone have pin outs for a 2017?

[vannatta20]

If you have a 17 L83 it will have an 3 pin fuel sensor in the fuel rail. You are correct to need the fuel rail sensor signal in Pin 41 of X1. You will want to run the 17 ecu with a 3 pin fuel sensor with the harness pinned correctly.

[Shrek]

From your description, you may have received a mix of components and wiring.

The wiring harness sounds like it may be pinned for a 2014 to 2016 Gen 5.

Take a look at the connector for the Fuel Rail Pressure Sensor - it is at the back of the passenger side Fuel Rail. A 4-wire connector is for a 2014 to 2016 engine, while a 3-wire connector is for a 2017+ engine.

When using a 6L80 / 6L90 transmission in a conversion, I prefer to use E92 ECM programming for a 2014 or 2015 - which obviously necessitates the corresponding wiring harness and Fuel Rail Pressure Sensor.

Just my two cents.

[msbweiland]

Yeah, the place I bought the engine/trans from sent me the wrong harness for the engine/PCM. The harness appears to be for a 2015, the engine is for a 2017. There are only a couple of differences between the ECM pin outs. One of them is for the HP fuel sensor. The 5V signal return is moved from one PCM connector to the other. Kind of a hassle, but I moved the wire and it starts and runs fine now. Still have some codes to work out, but that may be from the bum harness I got. Ordered a new 2017 harness from GM and I will modify it as needed. My fuel sensor has 3 wires.
Good learning experience for next time. One, don't order parts from an idiot and two, always make sure the harnesses match the engine exactly.