Do I have the right DME?
 

Hi, folks. I have a 2000 S that I bought last winter. While tinkering with the car, I apparently fried the DME. Rather than having the DME rebuilt, I purchased a DME/Immobilizer/Key Fob kit from a salvage yard, and installed it. It came from a 2002. The installation was successful, and I was able to run my car without problems (mostly).

Ever since the swap, my cruise control light has remained lit on the dash regardless of the button position on the stalk, but I have no cruise control. I have always attributed this to the thought that the "new" DME came from a car that didn't have cruise. I figured that I would just need to take it to the dealer to have the cruise map turned on in the DME. I had never bothered with it until now, as cruise is a luxury, and didn't really affect my driving.

However, in driving it this spring, I discovered that my A/C compressor doesn't seem to be working. I decided to take it to the dealer to fix the A/C and the cruise. The dealer states that he read a CAN-BUS error, and that my '02 DME is not compatible with my '00 car. I thought that I was fine, as long as I didn't get an '03+ DME. The salvage yard is willing to work with me to find a '00 DME, but they say that they have never heard of an issue like this.

SO, the big question is......do I need specifically an '00 DME/Immobilizer/Key Fob, or is there some other issue with my '02 DME?

Thanks for the assistance!

I'm not a pro, and I hope a pro can chime in here and help you. My knowledge of these systems (relatively the same for other vehicles) is that all CAN-bus controllers have software in them that needs to be downloaded into a new controller that's being replaced. Since 2000-02 uses DME 7.2, your 2002 DME controller would most likely work but would need to be programmed to mate up with the rest of the controllers on the CANbus. The other controllers you have (key fob, immobilizer) would also have to go thru this reprogramming if they are replacing their existing counterparts.

The dealer found that CANbus error because there are controllers on the network that are not properly mapped. The A/C doesn't work because the A/C controller has to talk to the DME as A/C puts a load on the engine and the DME has to consider this in its load calculations -- this communication is not happening (think of it as being similar to a computer network with IP addresses).

A dealer or indy can fix all this for you but it's all labor and will cost a lot.

Sorry I can't offer you any solutions.

Regards,
paul...

In 2000, the DME did not use CAN bus technology, in 2001 the DME had some CAN bus routed systems, in 2002 the DME use of CAN bus technology was more widespread. So while the DME software version remains the same, a lot of other things are programmed differently. It is my understanding that this can be overcome by reprogramming, but that is going to be costly and time consuming as it requires the use of a PST II or PIWIS system.

You would probably be better off getting a quote to repair the original unit, or find another 2000 DME.

JFP,

Thx for jumping in here (and helping Black Stallion) and for the education (for me)!

Regards,
paul...

Thanks, JFP. That's pretty much what I gathered as well, though my understanding of which years used it was off. Regardless, my dealer (who surely has a PIWIS or PST-2) has never expressed an ability or desire to actually re-program the '02 DME.

I guess I'm on the look-out for a used '00 DME. I will swap you out for a great '02 DME!!! :p

I'm guess I'm still a bit surprised that the car even runs with the '02 DME. Am I correct in thinking that I won't need a new immobilizer/key fob, just the right DME?

Alan

The correct DME will accept the IPASS codes for your immobilizer, etc.

JFP,

Forgive my ignorance, but are you saying that I DON'T need to have the dealer re-program the next DME that I get? That I can just find a DME from a '00 Boxster S (manual), plug it in, and it will communicate with the immobilizer by itself so that my car will start? Thanks for your expertise!

Alan

No, it will not communicate all by itself, it has to be coded.