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How to - Upgrade to a 996 Instrument Cluster


JonHoward42

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Following on from my successful retrofit of cruise control a while back (http://www.BoXa.net/forum/index.php?showtopic=61570&hl=) the next mod I wanted to tackle was the installation of a 996 instrument cluster. I had a few reasons for wanting to do this:
- I liked the idea of having the oil pressure gauge. My old MX5 used to have one, my MGB has one and it's nice so see exactly what the oil pressure is at any given time.
- I liked the idea of having a voltmeter. Again, my MGB has one and since I had the alternator fail on the Boxster a year or so ago, it's nice to see things are working as they should!
- I prefer the look of the 996 dials. They are very similar of course but I prefer the typeface/font used on the 996 dials.
- I already have the full leather interior with the nice stiching on various parts of the interior but Porsche seemed to cheap out on the Boxster's instrument cowl with just a thin covering of leather on the top surface while the 996 has a nicely stiched leather covering.
Anyway, decision made, I set about researching what parts would be necessary and what work would be required to carry out the job. I found a number of reasonable guides online and one in the Pelican Parts '101 Projects for your Porsche Boxster' book. For example:
So the physical installation seemed pretty simple. At a basic level, the 996 instrument cluster installation is pretty much plug and play albeit with the addition of one cable and an updated oil pressure sender unit for the oil pressure gauge. And then there is some coding necessary to finish the job properly, though the cluster does seem to basically function without any extra coding.
So, what follows is my experience of installing a 996 instrument cluster in my MY2000 2.7 Boxster. The main steps I had to go through were:
- Obtain a suitable 996 instrument cluster
- Obtain a suitable 996 instrument cluster cowl to match my interior colour
- Install the 996 oil pressure sender unit
- Run a single cable from the new oil pressure sender to the instrument cluster
- Perform some recoding on the instrument cluser to keep a PST2/PIWIS2 happy
- Fit the 996 instrument cluster
- Sit back and have a beer!
As before, I would like to make clear is that is merely my experience. I am certainly not a qualified expert in this field but I did get a successful outcome after doing research and using a decent amount of logical thought and common sense. If you wish to go ahead and do the same, it is at your own risk! :-)
Also, this is quite a lengthy report. Sorry if it seems a bit long winded but I wanted to include as much detail of my experience as possible in the hope that others might find it useful.
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Part 1 - Shopping List

Thankfully I didn't need quite so many parts as for the cruise retrofit. I needed the following:
- 1 x 996 oil pressure sender unit (996.606.203.02) @ £45 from OPC
- 1 x VW electrical connector (000.979.010 E) @ £4.56 from local VW dealer
- 1 x 996 Instrument cluster (996.641.105.02 70C) @ £110 from eBay ** See 'Part 2' for more options **
- 1 x 996 Instrument cluster cowl (996.552.060.02) @ £50 from eBay
- 1 x Hazard Warning Lights button (996.613.121.00 A2) @ £13.54 from OPC
- 1 x Surround ("Rosette") for above button (996.552.470.01 C53) @ £10.76 from OPC
NB: The pert numbers for the Instrument clsuter cowl and also "rosette" relate to "Graphite Grey" versions as that's the colour of my interior.
Also, only the "Rosette" and the actual button for the hazard warning lights was required, the actual switch (the electrical bit behind) seemed to be the same as the on from the Boxster so I requesed the original part.
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Part 2 - Choosing the right Instrument cluster


This seems to be a bit of a minefield of part numbers - looking through PET there seem to dozens of the damn things!


Fundamentally, there appear to be two main types of cluster:

- Older version for pre-CANbus cars (986 pre-MY2001). These clusters have BLACK, WHITE and BLUE connectors on the back and feature the older style digital segment displays.

- Newer version for CANbus cars (986 post-MY2001). These clusters have BLUE, WHITE and GREEN connectors on the back and feature the newer dot-matrix style displays.

NB: From what I understand, these two types of cluster are not interchangable.


A few other things to consider:

- Forget trying to use a cluster from a GT2 or GT3 - The may look cool but I don't think these can be made to work

- Forget trying to use a cluster from a Carrera 4 - I think these will work but the fuel level will be out of whack as the C4 has a different shaped tank and different sender unit. I realise PST2/PIWIS2 does have the option to do fuel gauge calibration but I don't know if it would be successful with a C4 cluster.

- There are different versions for tiptronic and manual (obviously)

- There are, of course, black and white faced dials


A quick look through PET turned up a number of possibilities for a car of mine's vintage (MY2000):

- 996 641 105 01 = Manual -MY99

- 996 641 106 01 = Tiptronic -MY99

- 996 641 105 02 = Manual MY2000-2001

- 996 641 106 02 = Tiptronic MY2000-2001

- 996 641 107 01 = UK Manual -MY99

Also, pre-CANbus MY2001 possibilities:

- 996 641 980 28 = Manual MY2001 C2

- 996 641 980 29 = Tiptronic MY2001 C2

- 996 641 980 30 = UK Manual MY2001 C2

- 996 641 980 31 = UK Tiptronic MY2001 C2


In the end I obtained a 996.641.107.01 from eBay:

ClusterfromeBay.jpg

Having spoken to another forum user who also performed this same mod, a 996.641.980.30 would also have worked for my age of car.

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Part 3 - Installation of 996 oil pressure sender unit
My next step was to install the 996 oil pressure sender unit. The original 986 unit is effectively just an on/off pressure switch to warn if oil pressure is dangerously low. The 996 unit has this function as well but also provides a feed to give a live reading of the oil pressure.
The process of swapping the 986 sender for a 996 sender is very simple:
- Disconnect the cable from the sender unit
- Use a 24mm deep socket to unscrew the old sender unit
- Screw in the new 996 sender unit and tighten with a 19mm spanner or crow's-foot wrench. Do not try to tighten by hand using the body of the sender unit, you'll probably damage it.
- Connect the original cable to the terminal labelled 'WK' (this is for your oil pressure warning dash light)
OilPressureSenderUnit.jpg
NB: This is not my photo (clearly) - I forgot to take a photo of this. The oil pressure sender unit is on the driver's side of the engine, accessible by removing the engine cover (roof in service position, remove storage/speaker box, remove carpet, etc).
The finishing part of this process is to run a cable from the 'G' terminal up to the instrument cluster. Some of the online guides for this suggest running a cable across the front of the engine, through the rubber grommet with the gear selector cables, along the central tunnel and then up to the instrument cluster. I didnt like this idea (sounded a bit messy to me) so I ran the cable towards the back of the engine bay (following the existing loom), into the boot and then followed the cable run I used for my cruise control retrofit:
4-01-LoomApproximateRouting.jpg
This photo is from my cruise retrofit guide (hence the number of cables) but I routed the cables up to the dashboard using the same path.
The cable from the the 'G' terminal of the oil pressure sender unit (which feeds the oil pressure gauge of the 996 instrument cluster) needs to added to the blue plug (or green for CANbus) for the instrument cluster, using the VW wiring connector. The pin number depends on the MY of your Boxster:
- 986 MY1997 to MY2000 (non CANbus) = Pin 9 of the blue plug
- 986 MY2001 to MY2004 (CANbus) = Pin 5 of the green plug (I've not personally done this on a later CANbus-equipped 986 but this is what I've read)
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Part 4 - 996 instrument cluster installation
I mention this step next as it depends on how fussy you are about doing a perfect job! :-)
At a fundamental level, I found the 996 cluster installation to be basically 'plug-and-play' at this point. Referring back to my cruise retrofit guide (or many other sources on the internet) the original 986 instrument cluster is removed quite easily by:
- Removing the mic cover and hazard warning button
- Remove the screw behind the mic cover and hazard warning button
- Pull cluster upwards
- Remove hazard warning light switch and three cables from back of instrument cluster
The physical installation of the 996 instrument cluster is the reversal of this process and, for me at least, worked perfectly:
first_fitment.jpg
(At this point, I acutally hadn't hooked up the new oil pressure sender unit so the oil pressure gauge was pegged at the top of the dial)
If you have an older, pre-CANbus car and you're feeling lazy, you could probably call it job done at this point. For me, all of the dials and gauges worked fine at this point though, of course, the odomoeter reading was that of the donor 996.
If, however, you have a newer, CANbus-equipped 986 and/or you want to finish the job properly, read on. :-)
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Part 5 - Coding, part 1 (which method to choose)
After trial fitting my new 996 dials, I found that basically everything seemed to be working, however, the odometer was reading the mileage of the 996 donor (happily only about 2,000 miles short of my actualy mileage). But, upon connecting my PST2, it gave a big fat "?" next to the instrument cluster and could do nothing further with the it. If I told the PST2 it was connected to a 996 rather than a Boxster, the instrument cluster actually came up fine (and everything checked out perfectly) but obviously just about everything else came up with errors.
So some sort of coding was going to be necessary to have the new cluster work properly with the 986 systems and keep the PST2 happy. Having done a bit of research and having spoken to a couple of forum members, there appeared to be two known methods:
- Modifying the contents of the EEPROM on the PCB of the instrument cluster
- Code and re-code the DME of the Boxster. The key steps are outlined in the Pelican Parts article - basically, recode the Boxster's DME as a 996, recode the instrument cluster then recode everything back to being a 986.
I didn't like the idea of coding the DME as a 996 then recoding it back to a 986 because,
a) I didn't have the necessary programming codes at the time, and
B) it sounded like a recipe for diaster! I had visions of my car being dead on a trailer going to a garage who would relieve my wallet of a big pile of money!
If, however, you're looking to try this coding/recoding method, I had a quick practice on the PST2 in demo mode, screenshots of the process can be found here:
- Coding to 996: Link...
- Coding to 986: Link...
Apart from access to a PST2 or PIWIS2, you'll also need your IPAS codes, specifically the 'DME programming code' and 'Immobiliser code'. In principle, you have the right to obtain these from Porsche but my local OPC told me in no uncertain terms that they would not provide them and to kindly stop asking! Having spoken to other forum members, this response is not uncommon but a quick note to customer services might help you, though they didn't even bother to respond to me.
Anyway, I set about working on the other method which involved editing the contents of the insturment cluster's EEPROM.
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Part 5 - Coding, part 2 (editing cluster EEPROM)
(As mentioned before, I've only tried this on my MY2000 Boxter and I know of a couple of people who have done the same on similar age (or older) cars. I'm not 100% sure if the following will be suitable for CANbus cars as they have a larger EEPROMs. I expect it will work but have no personal experience of this.)
This process may sound a bit scary but really isn't that tough.
First things first, the instrument clusters will need to be opened up so you can get at the EEPROM on the main PCB:
InstrumentclusterPCB.jpg
The PCBs of both 986 and 996 clusters are the same.
And then connect a suitable EEPROM programmer. I was fortunate enough to be able to borrow a GQ-4X like the ones in these photos from 986forum:
DSC04026+croppe1361759731.jpg
DSC04031+cropped1361848629.jpg
Then use the software to pull the coding off the EEPROM of both 986 and 996 instrument clusters:
996capturescreenshot.jpg
Keep a backup of both, incase you need to restore either (or both)!
With EEPROM dumps from both clusters, the next step was to identify the differences between the coding of both, determine which items needed changing and test out the changes. Below is a comparision of the EEPROM dumps from both my original cluster and that of the 996:
first_attempt.jpg
The items highlighted in green at the differences between the two code bases. (You may notice that I'd actually already made a couple of changes to the codes so the mileage and VIN were transferred to the 996 code base along with part of the vehicle type)
I had already been in contact with a couple of forum members and done a bit of research on the function of some of the sections of code. There were two courses of action ahead of me:
- Use the original 986 code base on the 996 cluster and make some adjustments (e.g. enabling voltmeter, oil pressure gauge, etc)
- Keep the 996 code base and modify it to support the 986 systems and mileage
I started with the first approach which basically involved using the 986 code base (with modifications to enable voltmeter and oil pressure gauge) on the 996 instruments. This worked fine and the PST2 could operate it perfectly but I noticed the calibration of the analogue speedometer was wrong because the 996 speedometer tops out at 180MPH but the 986 coding is expecting the same position to read 160MPH. Damn!
So, my options were to either identify and copy the calibration data from the original 996 code dump or make the 996 code base work properly with the 986 systems. With a bit of trial and error I figured out roughly where the calibration was held (see image below) but could not reliably get it implemented into the 986 code base. Damn, again! So getting the 996 code base to work correctly was the way to go.
Now the process of using the 996 code base is loosely documented on a couple of forums but I found the steps to change the vehicle type to 986 didn't acutally work and the PST2 still saw the instruments as from a 996. So more investigations were needed to dentify a previously undocumented section of code, necessary to successfully change the vehicle type.
Pulling together information from a few sources (a couple of very helpful forum members and a few other internet forums) plus my own investigations, I've compiled an illustration of the sections of code, their basic functions and the options:
HexTable-final.jpg
NB: The 'mystery byte' values detailed above are what worked for me and were basically what the 986 cluster and 996 cluster had by default. Having spoken to others, their 986 cluster actually had a different value by default. Why I'm not sure, possibly this difference is to do with manufacturing date, vehicle type (2.5L vs 2.7L) or something else entirely. So, if the value I've provided above doesn't work for you, try using the default that came with your 986 cluster.
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Part 5 - Coding, part 3 (Creating the final hybrid code)
With the above information in mind, I could successfully modify the 996 coding to work correctly with the 986 systems, keep the PST2 happy and maintain the correct calibration of the analogue speedometer.
From the base 996 coding, I had to make the following changes:
- Copy the correct mileage (copy 00000000-0000000f from 986 code base)
- Change the VIN (copy 00000018-00000028 from 986 code base)
- Set vehicle type to 986 - part 1 (set 00000035-00000036 from ’09 96’ to ’09 86’)
- Set vehicle type to 986 - part 2 (set 0000003b from '08' to '06')
- Ensure voltmeter was enabled (set 00000056 to '01')
- Ensure oil pressure gauge was enabled (set 00000049 to '3c')
Part 6 - Reassembly
At this point it was a simple matter of writing the 'hybrid' code back to instrument cluster's EEPROM, reassembling the cluster and physically refitting said cluster back into the car. A quick run through with the PST2 showed everything as working as it should.
Time for a test drive followed by a beer!
Job done!
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Jon - another fantastic comprehensive write-up, well done.

For anybody thinking of doing this but a little daunted, don't be, just follow Jon's instructions logically and its straightforward.

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Thanks for taking the time Jon to write it up - it will sure make it easier for others to follow.

Its also good to see the eprom contents written up rather than sprawled all over the net...which as we know is a bit tiresome!

We just need to find out what causes the cruise to stop working for me (and as did for Duffy) when swapping the cluster... and its interesting yours is ok post swap.

Just for reference of others reading... cruise is coded (with pst/piwis etc) in the dme not cluster, so thinking is that cluster should not affect cruise, but we know it can.

I wonder if there are any tech docs focusing on the real under the cover operation of cruise.... that may show something...

David

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pretty sure cruise is part of the motronic , as its a standard function in that.

I could read a 986 with and one without the CC function

That would be excellent if you could and post the eprom contents.

I need to review the coding as its a while since did mine, Duffy said that cruise is coded in cluster and dme, but I am sure I just did dme and with the old 986 clocks I had it worked perfectly.

David

David

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I will try and make an xdf (TunerPro) file to make cluster editing foolproof.

I don't have much porsche specific tools yet like pst2 or durametric , so my hacking tools are very low level , its very good to see others are just as inquisitive and enthusiastic about getting hands on.

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  • 1 month later...

A bit of a late revival of this thread, I know. I have been trying to read my eeprom using a generic Willem programmer called a TL866 with a soic clip. When I read, all I get is a series of 0000 FFFF 0000... I have definitely identified the right chip in the programmer and I've made sure the clip is attached properly. Am I making some kind of schoolboy error?

Thanks.

Alan

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I used that programme first as well but had no luck with it so bought the GQ-4X myself, also if you have a cheaper SOIC adapter then the pins can not make contact properly.

I bought a 3M connector in the end which worked perfectly.

I am putting my GQ-4X up for sale as I no longer have my Boxster ;)

Dan

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  • 2 weeks later...

I successfully dumped the contents of my EEPROM, modified it and uploaded it this evening. I have a 996 and did all of this more out of curiosity than anything else. I also successfully modified the odometer reading (and put it back again!). There's no checksum to worry about.

Just a few comments about my experiences with the process: I originally tried reading the eeprom using one of these http://www.ebay.co.uk/itm/USB-MiniPro-TL866CS-Universal-BIOS-Programmer-EEPROM-FLASH-8051-AVR-GAL-PIC-SPI-/221092473435 but had no luck. In the end I bought the GQ-x4 from danch. Cheers! Even then, I had problems because it was very hard to get the clip to sit properly on the chip. It took me many goes and a firm hand holding the clip to get it to read correctly.

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  • 3 weeks later...

Hi

I'm looking at having a go at this but wondering if any of you know how the mileage encryption works so I can set the mileage correctly, the first line seems to have all the same hex code in it .

Thanks

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Thanks for taking the time Jon to write it up - it will sure make it easier for others to follow.

Its also good to see the eprom contents written up rather than sprawled all over the net...which as we know is a bit tiresome!

We just need to find out what causes the cruise to stop working for me (and as did for Duffy) when swapping the cluster... and its interesting yours is ok post swap.

Just for reference of others reading... cruise is coded (with pst/piwis etc) in the dme not cluster, so thinking is that cluster should not affect cruise, but we know it can.

I wonder if there are any tech docs focusing on the real under the cover operation of cruise.... that may show something...

David

Hi - not sure if you ever sorted this but cruise is encoded in BOTH the DME and the cluster you have to have to enabled i both for it to work properly. It gets even more complicated in the later 997's with the gateway having to be coded as well !!

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  • 1 month later...

Jon, Great write up...best I have seen on the net...many thanks. Hoping you can answer my question.

Some back ground- I have a 1998 Boxster in which I just installed a 1999 3.4 996 motor. Car runs great!

I had my original 986 ECU flashed with a 996 ROW flash. At the same time I installed cruise control and

a 996 six gauge cluster.

When I installed the gauges I ONLY used the analog gauges and I kept my original 986 mother board when

I re-assembled the cluster to put back in the car. I did not use the 996 mother board at all. Lights all worked and digital displays all worked and showed correct car millage. Obviously, volts and oil pressure gauges did not work.

My question is do I have to do both things to get the volt/oil pressure gauges to work? By two things I mean re-program the flash chip in the 986 mother board with a EPROM programmer and then have Porsche use their PWIIS units to turn on the gauges? Do I need to do both things to get all to work?

Thanks for all your efforts and help, Bob

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Hi Bob,

I'm glad you're finding the writeup useful.

Good job on the 996 engine install BTW, I believe we have a forum member doing a similar job at the moment.

In answer to your question, I believe the main boards in the 986 and 996 clusters were the same. Initially, I had the 986 code base (with mods to enable voltmeter, oil pressure gauge, etc) installed on my 996 cluster and it all worked perfectly, except for the analogue speedo calibration. The analogue speedo calibration was the main reason I had to go for the modified 996 code base.

On that basis, if the operation of your main dials is acceptable right now, I imagine you'd be fine to continue with the code base on the cluster as it is and simply enable the two gauges by changing the contents of the hex addresses detailed above (with the EEPROM programmer). I don't think you can simply enable/disable those dials with a PST2/PIWIS2 - it's a standard function of a 996 cluster or a hack on a 986 cluster.

Reflashing the cluster with 996 coding would probably do the job too and mean you don't have to worry about the manual EEPROM coding.

I'm not sure if the DME running 996ROW code would complicate the matter or not. Fundamentally, probably not, but it may make things trickier if you want to reflash the cluster with 996 software using a PST2/PIWIS2. It's not a combination I've tried! :confused:

Out of interest, when you did the engine swap, was it just the DME you reflashed to 996ROW or did you have to do the other modules (e.g. ACU, climate control, etc) as well?

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Thanks Jon for speedy reply. To answer your question. All I did was flash my 986 DME (original car DME 5.2.2) to a 996 ROW map. The 3.4 motor came out of a car with the same DME number 5.2.2. Everything worked great ( ACU, climate control,etc.) As a result I was also able to remove my secondary air pump and assorted vacuum lines. Something you do not have to be concerned with over there. Vacuum leaks are a big pain over here.

If I re-flash my cluster with the 996 coding would I not lose my original millage and ven. numbers?

Thanks again, Bob

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