DIY Performance Shift installation Write Up.

I wrote this on the KC Boards, but I figured I would share it here. Not sure if the site already had a write up with detailed pictures of the PCM, but I thought I would share it with you all

I would have made more pictures but the 8 image limit jacked me on that. I will post them in the following post.

Anyone who has a 2000 GTP knows about this cause it came standard that year, but all other GT and GTP's GM in their infinite wisdom removed the feature from our cars. The PCM still has the option available and most cars with the DIC that has the boost gauge showing will have the words PERFORMANCE SHIFT just below the digital numbers. If you look closely you will see it there.

These are some pictures of the wiring of the PCM to allow the use of the performance shift in our cars that do not have the option already available. Keep in mind, you will need either to purchase a PS shifter handle, I got mine from Ed Morad for about $40 +shipping. PFYC has or had a complete kit for about a $100 - $150 bucks or you can just go to your local autoparts store and buy a cheap switch, that has a ground, to make the PS active and inactive. Or other aftermarket shifts can be used that have the OD feature in the handle(shifter).

You can use any gauge wire really. I know Swash used a 14 gauge stranded wire, I used a 12 gauge solid core wire for my installation. Either one will work well. The only problem with the 14 gauge is that it takes a bit longer to thread through the pin hole for #21 on the serial connector that leads to the PCM. The 12 Gauge was easy to slide through and the connection a snap.

Here are some photos of the PCM wiring part of the installation. I left off the wiring of the inside of the car and I will explain at the bottom why.

The connectors I bought from Radio Shack. Part NO 276-1428

Next you need to find the bank that has Pin 21 on it. Facing the engine bay, there are two connectors going to the PCM. The top connection, the Clear Plastic One, is the one closest to the firewall of the vehicle.



Simply use an 8mm socket to losen the bolt and then simply pull on the sides of the connector. Dont pull on the wiring. Once you have removed it, you will see an orange gasket, its reusable. Then you have to remove the gray plastic casing that covers the pins on that connector.

There are six spots on the plastic covering you need to push inward to get it to release. I used a small bladed screw driver to provide upward thrust as I pinched the sides together and the popped off each end of the gray housing. The two center ones you need to use the blade of the screw driver to pinch them inwards. There are slits where you place the screw driver in to perform the task.

Now you need to locate Pin 21 on the plug. It is to the right of the bolt on the upper bank, first one to the right of the bolt.



Then I took my 12 gauge wire and pushed through the rubber grommet that is inside the hole leading to the socket for Pin 21. Solid core worked well here cause it easly punctured the grommet without issue.



I then removed the wire from Pin 21 and then put the conector on to the wire. I used a small amount of soder to make the connection solid to the post connector.



I then pushed the newly created connector through the grommet of Pin 21.



Once the connector is fully inside, you will hear, well more likely feel, a click once the connector is in place. And it will look like this.



Once you have done that, you can reseat the bank back onto the PCM. Make sure the gasket is lined up correctly. I did this by removing the gasket and placing it over the clear plastic that protects the pins. It made it easier than trying to stretch the rubber back over the PCM and then juggle the bank to reconnect it to the PCM.

You then use approx 7lb of Torgue on the bolt to resecure it. Then replace the gray covering over the wires and then rezip tie the two end points that hold the wiring to the grey cover. Place the PCM back where you had it and you are almost good to go!


Now for the inside of the vehicle. You need to a run the wire through the firewall on the passanger side of the car beneath the carpet towards the center console. Then feed in enough wire to wherever you want to place your switch. I used my shifter as my choice of connection to perform this mod. You will need to make sure you have a solid ground from the switch and your red line (you can use any color really) is connected to the postive side of the switch.

The last important thing to note that Swash discovered is that you need to make sure your PCM is setup to know it has the performance shift available.

Here are his tips for checking that.


1) Calibration Data-->Transmission-->Shift Switch-->Shift_Switch_Type = set this to 1 (default is 0)

2) Calibration Data-->Transmission-->Shift Switch-->Discrete_Switch_Debounce_Time = 25 (currently yours is 200 (I believe this is the factory default))


Once you have those things done, you should be good to go with you own Performance Shifter!

I hope this helps anyone wanting to do this mod in the future

Pictures of the Connectors used to install the Performance Shift.

I've done this myself. However, I did not know that you could get those connectors at radio shack for running in the pcm. Interesting.

Yah, I tried looking for those connectors there, and without knowing the size, I looked through like more than a dozen drawers and saw soo many. Then my stupidy gave way and noticed ZZP had already sent one of those connectors attached to the wire already! Gee golly!

Very nice write up!

i thought the older models are always in pref shift... if not and i add this mod to the 97 how would i add that feature in the pcm? im in the market for a pcm and i think the im going to cough up the money for an overkill one could i tell him to add that in?

what the big difference on pref shift?

No early models have the perfshift button. Later models 02? and newer the cars are permenant perf shift. Not sure if SEs came with the option or not.

so whats so great about pref shift??

Say if you have a PTuner, you can adjust your shift point and all for WOT and PE so you can use perf. Shift, and use perf. shift off for like cruising situations.

its fun to have an extra button

is this perf shift avail. for my 97 gt?

Well it affords the option of Skip Shifts, Speedlimiter turned off, and a few other goodies along the way.

As for the comment about perma performance shift, I am not to sure about that one. Its not the best on fuel economy. I use mainly for the track and if the club is out goofing around. But for highway applications I just stick to regular driving mode, nonperformance shifting

I would imagine it has it, the only way to know for sure is to have someone hook up a powertuner to your PCM to read the transmition to see if that option is available as I stated in my original post. Then you will have your answer

Sorry I could not be more specific than that.

I love the way it shifts when its on, but cant stand the way it shifts w/o it. Feels like the tranny is slipping or the shift shock feels weak.............

Not true. Perf. shift on a stock PCM only raises the shift points while WOT. But increases line pressure in the tranny for firmer faster shifts (less wear on tranny clutches by the way) If you drive normal you will not notice any loss of MPG. If that was the case GM and there efforts to keep their CAFE numbers low would have left it driver optional in the later models not permanently program it in. Six months after I bought my car (50 someK on the ticker)I drove it across country Maine to California left the perf shift on all the time and averaged 32-34 mpg. With a high of 36.

So what's so special about it? On the earlier models it raised line pressure in the tranny, raised shift points slightly (under WOT)and various other sundry items. But mostly like Ord said it's fun to have an extra button. A buddy of mine drove my car when I had to pick up my motorcycle he called it the james bond car cause all the buttons and gadgets.

Some aftermarket PCMs need the perfshift to be engaged to take advantage of the tranny tuning upgrades. Hense the write up that started this thread

The speedlimiter is not controlled by the peformance shift option. Only transmission parameters are changed.