I have a question... 2001 1500 4x4 auto. My original pcm came with only 2 02 sensors. I got the dreaded memory checksum error and the truck would just randomly die while driving. Not fun on winding roads in the mountains. So I went to pick n pull and got pcm for same year same everything... slapped it in. Truck fired right up.. only thing is this pcm was flashed for 2 upstream 2 downstream. So my injectors aren't being pwm'd as efficiently as it should.
question part: I wonder if I could just "y" of the existing 02 sensors to the signal and heater circuits of bank 2 sensor 1&2 on new pcm

Any thoughts?

 

Did the PCM that you picked up from the pick and pay have the same part number on it that the original PCM had on it?

 

I would have to double check... but I doubt it. I was kinda in a pinch and I just plugged it in and it fired right up. My mileage reads the same as it was before. Which I thought was kinda weird but nevertheless there's just a couple little kinks I'm trying to get past. I have the service manual which is immensely helpful except that it's like 3500 pages and it's on my phone. But from what I saw on the service manual the only model that had only 1 upstream and 1 downstream was the 5.9l HD. I got 1500.

I'll double check part numbers when I get home

 

Sounds like you got a cali emissions PCM...... what's the 8th digit of your VIN?

 

I'm still leaning towards just jumping the signal wires tothe pins on the pcm that their aren't any sensors for.. it will have no idea that it's not looking at 2 02 sensors that aren't their.

Only other issue I'm having is my alternator won't charge with the pcm. Same with my original pcm so I'm pretty sure I got a wiring issue somewhere. I may just go back to pick n pull and get the whole wire harness or maybe 2 of em

 

Using external voltage regulator to get by

 

Z is eight digit

 

Ok, that's not the HD. Do you know what it was on the donor truck?

Twinning your O2 sensors will likely work, just as you say, the computer won't have a clue. There IS, however, the possibility that the computer will figure it out though..... It may vary mixture from what it sees as one bank, to the other, and expect to see a signal change from one of the sensors...... Not sure how it will interpret seeing the change on both....

 

Yea its it's a half assed attempt at best. Then there's the heater circut. I'll just see what happens go from there.

I'm hoping I can get the original board out from that sadistic gel they used. My problems began when it got hot outside (100+°). I noticed it would continuously die when it was hot out... so I pulled pcm off the firewall and would set it up by my windshield wipers and pack ice behind it and it would drive flawlessly until the ice melted. But I was usually pulling in the driveway by that time. So obviously there's a leg that's pulled off the board. Would be nice if soldering could repair the original

 

You can typically find good used PCMs on eBay. Just search for the PCM part number from the original PCM off your truck and you should be golden. You can also try car-part.com.