Blackbox to 12200411 PCM Swap

Swapping a 12200411 (Blue | Red) or 03+ (Blue | Green) PCM into an early OBDII GMT400 or M Van (96-98) is not difficult. It is mostly just simply moving pins from the Blackbox connector to the 411 PCM connector, however there are a few splices that need to be made. Therefore, being able to crimp-solder-seal is a skill you'll want to have.

The first thing you'll want to do when considering the PCM swap is to obtain the correct wiring file for your application. I can send you Pinouts

Things you'll need for the swap:

1) 12200411 PCM or 03+ PCM

2) both 80 pin PCM connectors

3) 2 red or green retainers and 2 blue retainers

4) a few extra PCM pins (maybe 5-6 extra depending on what truck you're working on), if you get your PCM from a junkyard, see if you can get the PCM, connectors/retainers, and a foot or so of the harness wiring. If you don't get the extra harness, you can get PCM pins from places like EFI Connection, I would recommend getting 10 or more incase you drop some or mis-crimp them, or something. They're pretty cheap, I like to err on the side of caution.

5) A tuning software like HPTuners, or I can flash it for you.

The 411 came in many different 2000+ vehicles, however its most notably in the 2001-2002 trucks, F-bodies, Corvettes, Express vans, etc. Any of these PCMs will work with the proper tune flashed into them. however, EVERY PCM will need a tune flashed into it to work, so no one specific PCM is better to use than another.

The 411 PCM will have a sticker located on the bottom of it which gives some information about the PCM so you can make sure it is a 411. What you'll want to look for is the Service number (SERV.NO.) 12200411.

Before you actually start the physical swap, you may want to address the tuning issues about this swap if you do not have your own tuning suite, as you will need the PCM flashed with the correct tune before this swap will work. If you plan on tuning the PCM yourself, you can do so after installing the PCM, but before actually starting the vehicle.

Now let’s look at the actual swap.

The Blackbox PCM is located on the driver’s side of the engine compartment in the middle of the fender wall, simply unplug the Blackbox PCM by removing the "locking" tabs, then unplug the connectors. There will be 4 of these connectors on the Blackbox, go ahead and unplug them all and remove the Blackbox PCM from the vehicle. If you have a 96 or early 97 PCM, you will also have a 5th connector, if you do have this 5th connector, what you'll want to do is un-loom about 8-10" of the wiring harness. There are 2 wires connected to the 5th connector, however all it is, is a jumper wire, so once you unravel back enough, you can just remove that connector and wire altogether.

Okay, now you should have all 4 Blackbox connectors there, and you should also have your 2 80 pin connectors there as well. First, you'll want to label which 80 pin connector is which, so that while you are wiring you do not get them mixed up. I'd suggest putting a piece of tape on them and labeling them C1 (blue) and C2 (red or green). Okay, at this point you'll want to remove the red or green and blue pin retainers from both 80 pin connectors if they aren't already. To do this you'll need something small and thin like a very small jewelers screwdriver or something similar. There is a small opening on either side of the retainers, use the small screwdriver to press in on the tab in those holes to unlatch the retainer, once both sides have been released, simply pull the retainer off.

So, you've got both 80 pin connectors ready and labeled with the retainers removed. Now consult your wiring spreadsheet and grab the Blackbox connector which corresponds to C1 (retainer color may vary depending on the vehicle you are working with. the spreadsheet will explain which colors correspond to which connector (C1, C2, C3, and C4) on the Blackbox). You will only want to work with ONE connector at a time. So, grab the Blackbox connector C1 and remove the retainer in the same manner as the 411 retainers. once you have the retainer off, go ahead and open up the back of the Blackbox connector.

Now what you'll want to do is simply follow the spreadsheet. Removing one wire at a time from the Blackbox connector and placing in its correct spot in the 411 connectors. ONLY DO ONE WIRE AT A TIME! if you try to remove a bunch of wires at a time you are going to make an error and have to spend lots of time and energy trying to trace down the problem afterwards. Save yourself the headaches, and problems and only pull and place one wire at a time, it would also be wise to verify the wire color and make any note of wire color discrepancy vs the spreadsheet in case you need to investigate something in the future. The spreadsheet has been used many times and is well refined. but in the early OBDII years, there were a few little differences in simple things like wire colors that we are not able to keep track of. The pinouts are all correct, but if you're like me, you'll want to double check stuff as you're doing it to prevent any issues.

To remove the pins is fairly easy, there are 2 little hooks that hold the PCM pin in place. There is a little tab the protrudes up on the outside of the connector, this tab needs to be gently pulled away from the PCM pin, and the pin itself needs to be pushed away from the connector body slightly, and down. Once the pin has cleared the little barbs that hold it up, you can simply pull the wire and pin out the back of the connector.

If you don't want to splice into the wires at the trans, you have another option, you can also splice into the gauge cluster harness and send those signals over to the PCM. If you want to do it this way, you'll need to remove your gauge cluster, then remove the cluster connector, and splice into the following pins for the trans signals:

Transmission Range Switch Signal A (blk/wht) = Pin 9

Transmission Range Switch Signal C (grey) = Pin 10

Transmission Range Switch Signal B (yellow) = Pin 11

Transmission Range Switch Signal P (white) = Pin 12

Now that you have it removed, you are ready to insert it into the PCM connectors. So, locate the proper PCM 80 pin connector, and locate the correct pin # on that connector. Take the PCM pin you just removed and insert it into the proper slot on the PCM connector. Go ahead and push it in all the way until the pin clicks into place.

Now go through and swap over all the pins and add the few splices like are detailed in the wiring spreadsheet. If you have an automatic transmission, there are a few more that may need to be added as well, (the spreadsheet will explain these and if it is needed for your application, but this may help). In the event that you do need to add these wires, the spreadsheet will refer to 'trans harness' which is on the PARK/NEUTRAL switch on the right (drivers) side of the transmission.

You'll be splicing into these wires and running an additional signal up to the PCM so that the PCM will be able to see what gear is selected. There are a few other splices that will need to be done up near the PCM, but which ones are needed will vary depending on your application, please refer to the wiring spreadsheet for that information. And for all the splices, I would recommend doing a quality crimp-solder-seal to get the best conduction and longevity of the splice.

After you have all the pins moved from all the Blackbox connectors, and you have finished all the splicing, you are ready to put the red and blue retainers back on the PCM connectors, simply align them and push down until they click into place. make sure the blue retainers go on the connector that you labeled as C1(blue), and the red retainers on C2(red).

Now that the connectors are completely pinned and already you can plug them into the PCM, there in only one way they can be plugged into the PCM with the red and blue retainers installed, but the C1 blue connector is on top, C2 red connector is on the bottom. The little bolts that hold the connectors in are 7mm, do not over tighten them, there are actual torque values, but I always just snug them up a little.

The PCM should fit in the bracket that held the Blackbox PCM, however the wire bracketry that slipped over the Blackbox PCM to hold it in place does not work on the PCM. you may want to fab something up to hold the PCM in there. But that likely isn't needed.

TUNING

In order for the PCM to work, it needs to be flashed with a proper tune. To do this, you either need a tuning suite to do this yourself. Or we can flash it for you.

You need to start with a 2002 Express van base tune. The express van is the key to why this swap works since the 2002 express used both the L31 vortec engine and the 12200411 PCM. So starting with the 2002 Express van L31 tune for your correct transmission, the following items need to be changed.

1) Turn off the VATS (Vehicle anti-theft)

2) Disable Alternator codes

3) Depending on your setup you may need to also disable the fuel tank pressure sensor codes, and possibly post cat O2 sensors. Your specific wiring spreadsheet will detail this information as well.

4) You should also program in your correct VIN number. You are able to put any VIN number in these PCMs