Need help with PCM not seeing O2 sensors

A little background: I bought a '71 Pontiac LeMans with a LQ4/4L80E swap that was 95% complete. The engine has LS3 heads, a rectangle port truck intake with cable throttle body, and a mild low end cam. The previous owner flashed the PCM with a mail-order base tune just to get it running and unfortunately I don't have a copy of the stock tune to work with. The engine/trans/PCM came out of a 2005 Chevy Express, PCM is a P01 (blue). The tune is set up as a MAF delete SD only, which is fine with me but I'm having trouble getting it into closed loop. Fuel System #1 Status always reads "OL - Not Ready" and the O2 signals hover around 450mV on both banks.

I've verified 12V and ground to the heater circuits and flame tested both sensors (they look new - not sure of the brand). The heater circuit resistance on both was between 16-18 ohms, which seems a little on the high side, but not out of range according to the info I can find. The high/low signal wires appear to be pinned correctly at the PCM, but I haven't had time to check continuity between the PCM and sensors. Before I start tearing things apart too much, I just want to make sure there isn't something in the tune that could be causing it to ignore the sensors. Latest tune and log are below:

Attachment 123269

Attachment 123270

Any help would be much appreciated - I'm new to tuning and just trying to learn as much as possible.

A 2005 Express van would be running a P59 controller and this computer is a P01, so possible that the wiring between the harness and what you have is incorrect??

Also this tune file is setup for a 2009-2010+ MAP sensor and not the MAP sensor that would come stock a 2005 engine.

The tune doesn't have anything wrong as far as the o2 sensors go. But the tune does need a lot of help to make it better.

And for sure you need larger fuel injectors if they swapped back to the older LQ4 injectors into the newer truck intake.

Thanks for looking this over for me! Believe me, I'm painfully aware how much work this tune needs...I went back through my messages with the previous owner and I was mistaken about the PCM being original to the engine. I knew he had told me it was a P01, but he had swapped it out for a LS1 P01 unit and I misunderstood him. I looked up the service # that HPT pulled from it and it came back to a P01, so I'm confident that's what I have. I'll pull the PCM tonight and check the O2 signal wire pinning and continuity to the sensors, but I was able to see the high signal wires without removing anything last night and they were at pins 66 and 69, which I believe is correct.

Once I get the tune sorted enough that it runs decent and won't blow anything up, I'm going to swap out the intake for an LS3 intake/rail/injectors to free up some hood clearance since I plan to add a shaker scoop in the future.

I'm sure the MAP came with the later model truck manifold, but I'll verify the part # to be sure. As long as it won't hurt anything, I'll leave it alone.

What's up with the VIN - N/A00000000000000? How was the thing programmed initially?

To get the right pinouts/diagrams, you need to know the year, make, model of the operating system. There is no one single pinout for "P01" or "P59" or any other PCM/ECM type. Sometimes things get changed from year to year and definitely from platform to platform, and the operating system being used is what determines the pin assignments.

Ok, so I was able to get in touch with the original owner and he emailed me the original tune file that he pulled with EFILive. I was able to download the EFILive software for free and view the file and got the info below:

Attachment 123282

While it's still not a full VIN, it comes back to a 2002 GM 2500 4x4 extended cab truck/van with an LQ4 engine, which should help me out considerably.

Case-ground sensors
Attachment 123288

Isolated-ground sensors
Attachment 123289

Ok, so I spent some time under the hood tonight and checked everything I could think of. The car has isolated grounded sensors, and both sensor heater circuits are wired correctly and I have continuity from the sensors to pins 66 and 69. Bank 2 sensor has continuity to pin 26 but Bank 1 sensor to pin 29 is open. I also don't have a wire in pin 63 at all, so there may be no reference ground on either sensor.

In the morning I'll trace the wire from pin 29 to Bank 1 and fix the problem there. As far as pin 63 being empty, if I jumper both tan wires from pins 26 and 29 to ground, will that work as a temporary solution to try and get this thing into closed loop?

The previous owner must have been using the 2002 truck wiring diagram for case grounded O2 sensors. Since the ground wire at pin 63 was missing, I cut both tan low signal wires in the middle of the harness and soldered all the ends together, along with another wire that I ran to engine ground. Success! Thanks for all the guidance, and I'm sure I'll be back as I struggle through the tuning...

Attachment 123312