What's wrong with my digital speedometer?
 

This just recently happened. My '99 Boxster is not my daily driver, but just my "fun" car to drive on pretty days. I got in the car a couple of days ago and noticed this "scratching" by the digital readout. Also, after driving a short distance, the check engine light came on, stayed on for about 15-20 minutes, then went off again. Any ideas?http://986forum.com/forums/uploads01...1347163201.jpg

I have ever turn off the airbag light with the Porsche cable
It said it can also turn off check engine light, read diagnostic trouble codes.
But not sure if can help you fix it up
It is called Porsche piwis cable

good luck

Donna pwis cables are meant for dealer repair and cost a lot. It would be cheaper to replace the entire cluster than to buy a cable in hopes of a reset, besides this problem doesn't look like a reset issue to me; looks like some kind of permanent display damage just my 2 cents. Another idea would be to go to a dealer with pwis and negotiate a reset, just know it might not work in your cost calculations, good luck.

It looks as if something is scratching it from behind. It is weird. Could there possibly be a loose wire or something behind there?

Tiny cats... Tiny tiny cats....

Loss of liquid crystal resulting in cavitation ;)
Sometimes called crazing, though this is incorrect.

It looks like you found the etch-a-sketch function.

'99 986 LCD speedometer
 

All,

I have a '99 986.
The LCD speedo is difficult to see unless you shine a light on it just right. it works and shows the correct speed, just the visibility. Is there a bulb that needs replacing or do I have to change the whole cluster?

Any info would be appreciated.

tim

Yes, the bulb is probably out.
It's fairly easy to remove the cluster to replace the bulb.

Instrument
 

Your LCD is gone. It can not be replaced unless you have unusual elect. repair skills.
If you want it corrected you will need a new instrument set.

You're replying to a 2 year old post :D

FWIW, the HSC ribbon is really easy to remove and reattach if the proper tools are used. These are 180°C ribbons.
If you have this problem, you can find a bad cluster with good LCDs and swap them out ;)
I'll do a full write up on the procedure soon.

I had the same problem with a 996 cluster that I swapped into my car. I couldn't find anyone willing to swap lcd's for me and I didn't think that I had the required skills. You can read about my experience here:
http://986forum.com/forums/general-discussions/43017-carrera-gauge-swap.html

FWIW, the information provided to me indicates that the problem with the lcd's is caused by contaminants that get between the layers of materials during the manufacturing cycle. Time and perhaps temperature change eventually cause the layers to de-laminate and the result is what you see in the original post. This seems to make sense, but I have not seen any information from an official source confirming it. Considering that Porsche eventually adopted a dot matrix displays in lieu of lcd's seems to confirm that this was a flaw with the technology or manufacturing technique.

If anyone needs cluster programming instructions, send me a PM with you e-mail.

I had this issue on my red car and two months later it started getting better. Now you cannot tell it ever had that issue. Whats up with that?

Sent from my SM-T310 using Tapatalk

cluster
 

Particlewave, I'd love to see a write up on how to replace the LCDs. I'm sitting on a 996 cluster that has all three LCD delaminated. I'd love to be able to swap my 986 LCDs into the 996 cluster but every tech I talk to says it can't be done without all kinds of special equipment. SHOW US HOW and we will owe you big time.
Thanks, Reebuck1

If Particleweave can provide an easy method for swapping the lcd's that would be great.

However there is another way to accomplish the same result. What you need to do is swap the entire board with the lcd's from your 986 cluster to the 996 cluster and then program the 986 board to think that it is a 996. You can actually swap the board and everything except the voltmeter will work fine without the programming. There may also be a speedometer error. The only special equipment you need is an EPROM programmer and a clip to attach it: http://www.amazon.com/GQ-4X-Universal-EPROM-programmer-full/dp/B009N9HHL4

PM me with your e-mail address if you want the full instructions. If you are a Renntech contributing member, you can view them here: http://www.renntech.org/forums/tutorials/article/377-programming-a-carrera-instrument-cluster-for-transplant-to-a-boxster/

You may also want to contact a Board member with the user name of GavinYuill. He has programmed several boards for folks.