Carrera Gauge Swap

[Reebuck1]

The learning point for me here was......I should have installed the gauges and cruise control BEFORE I put the 3.4 996 motor in the car and before I had the 986 DME flashed with a 996 ROW flash.!!!!!!!!!!!!!!!!!!!!!!!!!!

I have been told and I now believe my problem exists because…my new cluster is still recognized as a 986 while my DME is recognized as a 996.
So when Porsche did a control unit scan as a 986 model with the Porsche tester it failed as the DME did not recognize it as a 986. If the DME is scanned as a 996 the cluster will also fail because it is not recognized as a 996.

I.E. am doing what I posted below.


Anyone see anything incorrect with this logic please let me know.

Thanks to all, Reebuck1

[Reebuck1]

Just so you can all see there really are gauges in the car!!

[Reebuck1]

Took my 996 analog gauges with my 986mother board out of the car.
Remember car ran well and most gauges worked ( except volt & oil pres.)

Put my 986 analog gauges with the 996 mother board in the car.
...CAR STARTED and ran well.
...986 analog gauges did not work...I was not expecting that!!
...Maybe it is ok because the DME thinks it is a 996 ROW DME and still can not recognize or is not programmed for the 986 analog gauges.

Intend to now take car to Porsche to use PIWIS to turn on all gauges in the DME.
...should now work because DME that thinks it is a 996 ROW can now recognize
a 996 gauge cluster (996 mother board is now in car) as a 996.

Once above is complete I need to reinstall the 996 analog gauges with the 986 mother board back in the car and hopefully all will work. I believe it can only work if I recoded the control chip in the 986 mother board to "TURN ON" the volt gauge and the oil pressure gauge. I believe the PIWIS at this point may still not recognize the 986 mother board but I will not care because all the gauges should be working.

HELP !!!!! If anyone sees issues with this please let me know.
Thanks for every ones help.........

Mistake made......When I original installed the new gauge cluster in the car I made a mistake. I put the gauge cluster in first and then installed the heater vent that goes under the steering wheel and runs up to the dash vent next to the drivers side window. When doing it I incorrectly placed the wiring harness that runs to the "BLUE PLUG" on the back of the instrument cluster "underneath" the vent. So when I tried to pull out the cluster it would not slide out far enough for me to disconnect the BLUE PLUG from the back of the cluster. It took awhile for me to figure out what had happened. I had to remove the whole vent system on the drivers side of the car. I could then move the harness to the top side of the vent, reinstall the vent system and then was able to pull the cluster easily out far enough to remove the plug.

[hemonu]

I do have a PST2 not the newer PIWIS as the dealers have today. It is true, that instrument cluster would nor be found during an automatic scan, but it still would be possible to manually select a 996 cluster, which is installed in a 986 and vice versa. In the coding section for the cluster there are option for OBC and cruise control, but I don't remember options for the voltmeter and oil pressure gauge. I think those are part of the basic firmware of the cluster. So the correct way would be to read the firmware of the 996 board, modify it with your VIN, mileage and car type and then flash it into the 986 board. So you may have to look for another EPROM programmer with can handle the eeprom on your 986 board or you may be stuck.

[Reebuck1]

Hemonu, Thank you very much for the information. Every little bit helps me get closer to solving this problem. It is very much appreciated !!!!!!

[Thumper]

I have installed several Carrera clusters in my '01 Boxster and have never run into the problems you guys seem to be experiencing. The only issue I've ever had was with the top light. I've just ignored it, but thought I would address it if I ever ran across someone with a PST2. As long as you get a cluster from a C2 and follow the instructions on Renntech.org, you should be golden. I installed my first cluster in 2007 and it's working fine to this day.

I am impressed with the talent to work on the circuit boards to replace bad displays, as I would never have the patience or knowledge to do so myself. All of the clusters I have used came from eBay and have only had one that was actually fried. I have only changed them out due to gauge face color and now have a silver faced set from a C2S. The clusters I took out are in other boxsters and all are working fine to this day. Never had a gas gauge issue, but I did have one that took forever to check the oil level. Also never paid more than $200 for a cluster. You just have to be patient and wait for a deal to pop up.

[Reebuck1]

Thumper the reason I am having so much trouble ( I believe...not sure) is because I have 5.2.2 DME.

I think I have now successfully recoded the EPROM chip on my 986 mother board to "TURN ON" the volt gauge and oil pressure gauge.
Topradio, your suggestion to try different chip designators on the GQ-4X worked and I was able to read the chip.

I reinstalled the 986 mother board with the 996 gauges but volt and oil pres. still will not come on. Maybe because the 986 DME that thinks it is a 996 ROW will not recognize the 986 mother board??

Topradio, I am wondering if I need to also code the bits with the GQ-4x that identifies the gauge pack mother board as a 986. This is found on line 00000030 of the code as shown on post #15 and #13. ???? If I change that bit to indicate it as a 996 do you think it will work??

Does anyone know if there is a limit on the number of times you can try and reprogram one of these EPROM chips??

I still intend to put the 996 mother board back in car and take it to Porsche to turn on the cruise control.

[Reebuck1]

Guys, Hoping I can get answers from some tech savvy folks out there to my questions below.
Even if you are not sure give me your thoughts and they could be the answer. Thanks


I reinstalled the 986 mother board with the 996 gauges but volt and oil pres. still will not come on. Maybe because the 986 DME that thinks it is a 996 ROW will not recognize the 986 mother board??

I am wondering if I need to also code the bits (with the GQ-4x) that identifies the gauge pack mother board as a 996. This is found on line 00000030 of the code as shown on post #15 and #13. ???? If I change that bit to indicate it as a 996 do you think it will work??

Does anyone know if there is a limit on the number of times you can try and reprogram one of these EPROM chips??

[Reebuck1]

Here is a picture of the 986 digital gauges mounted on the 996 motherboard. You will note there are no digital gauges displayed. All you see are the lights normally behind the digital gauge faces. Reason.. the 996 digital gauges are defective and I removed them hopping I could attach good gauge faces later. But I was unable to find these digital face plates anywhere or get them repaired anywhere.


Next is the 996 analog gauges with the 986 motherboard and 986 analog gauges shown in their respective cluster half. Ready for assembly and installation in the car.


This picture shows the 986 motherboard but with a close up of the chip we have all been referring to 93c56B. It is located just to the left of center about 1/4 of an inch above the large square white digital gauge face. It is a small black chip with 4 small silver connections protruding out its top and bottom.


Last is the 986 motherboard cluster with the 996 analog gauges fully mounted in the car but the two outside gauges (volts & oil pres.) are not working.


I have been unable to get anyone to respond to my last questions on how to proceed so here are my next steps.

1) In the next few days I will try and recode the 986 motherboard so that it thinks
it is a 996 motherboard by changing the two places on the EPROM chip that allows you to select 996 or 986. If that works I'll post the exact bits and location needed to be changed. If the gauges still do not turn on I am lost as to what to do next.

2) Even if step 1 above does not work I will put the 996 motherboard back in the car and take it to the Porsche dealer to TURN ON the cruse control function with their PIWIS. I believe they should be able to do this because the 986 DME that thinks it is a 996 ROW DME should then allow the 996 motherboard to communicate with the 996 ROW flashed DME.

I HOPE !!!!!

If step one works I will still have to follow step 2.

Again if anyone sees something wrong here please let me know.

[KevinH1990]

I sent you an e-mail with the file from my cluster attached. My best suggestion is for you to try to upload it to your cluster and see if that works. The process for programming the EPROM chip has worked for several people. You may be correct that your engine swap is preventing it from working for you.

I know this has to be frustrating, so I wish you the best.

Regards,

[Reebuck1]

Kevin, Got the e-mail....Thanks.
This keeps getting more interesting as I go along. Volts and oil P. still do not work but my digital gauges on the 986 mother board are now showing speed in KPH instead of MPH, interesting. The app that runs the attached files is called "Hex Editor Pro" and can be down loaded for free so you can read the files. Sent files to you but can not up load them on this site.

'986 chip' was my original data on the 986 mother board.

'986 chip adj." is the latest update that I have made to the 986 mother board.

"Kevin chip file "is your chip data

"ubsfile996" is the data from the cluster I took the 996 analog gauges from

Do you have any kind of sheet that tells you which bits control which function? or at least which bits control cruise control and top light?

I think I am getting closer but am still some what lost.





Thanks again for all your help. Bob

[Benjamin]

Here are my recollections from 2 years ago when I did this mod. As a reminder, I had a perfectly working 986 cluster and purchased a 996 cluster with a bad LCD. I kept my 986 motherboard, so my mileage, VIN, and fuel gauge calibration stayed. There were two bits that I needed to change in order to enable the voltmeter and oil pressure gauges.

I tried to buy a less-expensive programmer, but in the end couldn't get it to work and bought the GQ.

I seem to remember the warning light layout had some differences between the two clusters. I'd have to dig through my pile to find the Carrera version and see what is different. I ended up putting the Boxster warning light template on the Carrera cluster.

Everything seems to work perfectly for me. I like to tinker and I don't like to pay dealers, so I saved money and learned a lot.

Benjamin

[Reebuck1]

Benjamin, This exactly what I am trying to do. Keep my 986 mother board and digital gauges but use the 996 analog gauges. Just like you my 996 digital gauges were defective. If you still have your original cluster EPROM
files and what you changed I sure could use them. Thanks for the post. Reebuck1@aol.com

[Reebuck1]

Looks like I made another mistake....received this great suggestion


Hi ,


One thing that jumps out is that due to the read being byte swapped by the programmer the wrong byte has been changed for the voltmeter. This is why the unit is now in KPH, you accidentally changed the byte that controls that function. (BB changed to 01 at x00005006)

I have put it back as it should be, changed the correct byte for the voltmeter and written it to a new file. Try uploading this and see how it functions.

The pressure gauge should be working with this program though, so I do not know why it isn't. Have you checked your wiring and have a known good 996 sender unit installed?

Cheers

I'm on it THANKS !!!

[Reebuck1]

Tried the below suggestion and........IT LIVES.......IT LIVES.....THE BEAST HAS COME TO LIFE!!!!

All gauges appear to be working and car still runs great.

I'll try and give a detailed break down tomorrow.

I want to thank all of you for all the help you have been kind enough to provide.
I obviously would never have figured it out by my self. It is unbelievable all the collective experience that exists on this forum. Great work guys !!!

[KevinH1990]

That's good news. It's always good when perseverance pays off.

I know the feeling - when I saw my voltmeter spring to life I couldn't wait to take a test drive. I had been working on installing the oil pressure sending unit, and I had not reinstalled the sound insulation on the engine covers. Even though it sounded like I was driving in an oil drum with people beating on it with hammers, I couldn't stop smiling.

Right now, I need to replace the oil sending unit in my car. Whenever the ignition is on, it stays the 5 level. According to some posts on Renntech, the sending unit is a part that often fails.

[Benjamin]

I was going to dig out my old EEPROM files this morning but it looks like you got it going.

When I started mine up for the first time after installing the oil sending unit, I thought it wasn't working properly because the meter just pegged at 5 and didn't move. After a few miles it settled down and started working properly. It looks like that's pretty standard, although that's probably not what's happening with Kevin if it had worked before and then stopped.

To isolate the sending unit as the problem, you can unplug the wire to the cluster, and then measure the resistance with an ohm meter between the metal body of the sending unit and the terminal you unplugged the wire from. With the engine off it should read an open circuit (infinite). With the car running and warmed up, it should read roughly between 15 and 90 ohms, depending on RPM. As you rev the engine, the resistance should change. I would probably do that first before spending the $90 on a new unit.

Benjamin

[KevinH1990]

I have my hardtop on right now, so access to the engine compartment is inconvenient. I'll check the connections and the resistance before I shell out $90, but there are numerous threads on Renntech indicating it is a fragile part. Oil Pressure Switch/Gauge not working - 996 Series (Carrera, Carrera 4, Carrera 4S, Targa) - RennTech.org Forums (There isn't much information on this forum because most cars have the stock sending unit that sets off the warning light.)

Normally, the gauge reads 5 bar until the oil warms up and then I'm usually around 3.5 with the car running in the 3000-4000 rpm range.

I was driving at about 70 mph one night when the gauge suddenly went all the way to the top. I thought it might have been a blocked oil passage until I realized that the warning light didn't illuminate. On one of my other cars I would be annoyed. To be honest, I was almost relieved to see that the sending unit is the common cause of this problem. $90 for a sending unit is a lot less than the cost of a new engine.

[Reebuck1]

Took a long test drive today and everything now works !!!
Proof for those that doubt....though for awhile I was in the doubter group:


I never could have done this without every ones help. AGAIN THANKS !!
I made a lot of mistakes along the way and I need to detail them and list them
on this site so others don't have to make the same mistakes. I will be out of pocket until Monday and will take the time to do it then.

Thanks again, Reebuck1

[KRAM36]

Originally Posted by Reebuck1

Took a long test drive today and everything now works !!!
Proof for those that doubt....though for awhile I was in the doubter group:


I never could have done this without every ones help. AGAIN THANKS !!
I made a lot of mistakes along the way and I need to detail them and list them
on this site so others don't have to make the same mistakes. I will be out of pocket until Monday and will take the time to do it then.

Thanks again, Reebuck1

That's awesome! Nice work and persistence too!

This is on my list.

Did you do the 4 Stalk post too?