So I am after some help diagnosing this.
There are lots of things I can do, and though I would like to have the car running yesterday - I have more time than money.
What I am particularly looking for help is isolating the problem.
I can probably manage to transfer the eeprom or whatever has the magical coding from an old key to a new key if that is the problem.
But playing arround with the key is going backward if the problem is the EIS or the ECU.
Oh, I forgot that in the "history" The car has been reporting "check engine electronics" for probably a decade.
There has been alot of advice in some of the posts. But it is all over the place and I need to try to isolate the problem before desoldering chips from the Key or trying to find somebody to clone my ECU or ....
I am gathering the EIS and the Key are at the top of everybodies most likely culprits list - would that be correct ?
If I pull the DTC from CAN/J1939 am I going to be able to tell whether it is the Key or EIS ?]
If the key is not turning you will not be able to connect an OBD2 scanner and read the codes (not engine related codes anyway, as the ECU is not powered up, so no communications). You need to be able to turn the key first. For EIS related codes you "may" be able to read codes from the EIS but only through the 38 pin diagnostic connector. The EIS is powered up and woken up when you insert the key. But you need a special type of scanner to read the EIS data. I never tried this with the key not turned.
Am I correct that the car will only recognize 8 keys - without resorting to electronic hacking of the vehicle ?
I thought it is like 3 rows times 8 columns but I may remember it wrong.
In any case, if the keys were made due to key losses (as declared), they may have been erased, due to theft presentation measures
Am I correct that the EIS is where the Key programming is stored ?
One of the places, but the EIS also needs to match the ECU and the ESL, as well as the keys.
It appears there are people who do key reprograming of EIS's - can I get my EIS "cleaned" do that I can add more keys ?
I am sure you can.
Can I verify that all the Key slots for my EIS are used ?
If you can read the EIS data, it will tell you key slots status
If the EIS is dead can I buy another off ebay and find someone to clone it from the dead one ?
You can get the chips transferred provided that the chips are OK,
If the key is dead does that typically mean - totally dead, or is it still possible to move a chip to a new key and recover ?
No, it can be partially dead (remote only, or ignition only) or totally dead (chip problem, common power circuit problem)
There are probably other questions and I probably have not asked the right questions.
But the first step is to isolate the problem - so given the level of expertise I have described how do I do that ?
You need to start from somewhere, and I would start from the key as I described previously. You can make a tool to try to isolate the problem too.
Some of the questions imply that I have read some things on this on the web and have guesses as to the answers.
But I am here asking people who hopefully know more than I do about MB's
Though I am begining to think that I am in the wrong business. That I might be able to pay my mortgage if I learn how to reprogram ECU's and EIS's and .....
Start with what you can do first. (Key tests).
And I get peved when I am told I need some 50K software hardware combination to reprogram some car computer.
I wrote the software to do that for tractors and skid steers and ....
It is not that complicated. The hard part is getting the secret knowledge needed.
And even if you can not get that. reprogramming most programmable chips is not all that hard either.
The hard part is knowing what to put in or take out.