I'm not sure if anyone here has specific knowledge on this, but I'm trying to figure out how the SKIM/ immobilizer works on the bosch ECU. I know its possible to delete the immobilizer since the VW guys do it pretty frequently, but I haven't seen anyone here talk about it.

In our system there are three things that have to work together for the immobilizer to let the vehicle run. The key, the SKIM receiver, and the ECU.

You can take a matched ECU/SKIM/KEY and install those into any CRD and it will allow a start.

Additionally each vehicle has a PIN, and as the owner you can request the PIN for free from any Jeep dealer, I got 3 printed out today, one for my daily, one for CRD#2, and one for my parts CRD.

The impetus for all of this is that I am trying to use a 2005 ECU in a 2006. If I can figure out how to delete the immobilzer, or reprogram the PIN for the immobilzer in the ECU, I should be one step closer to making it work.

It seems to me that the MPPS pulling the EEprom file is not enough - otherwise we would not be able to copy tunes around. EG if you loaded someone elses 808 Hot tune it would make your ECU look like theirs, VIN PIN and all, and it wouldn't run.

This makes me think the VIN information, vehicle mileage, PIN, and other vehicle specific stuff must be saved in the ECU in some other eeprom than the MPPS accesses.

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http://www.Colorado4Wheel.com
"Its not about what you can DO with your Jeep, its about where you can GO with your Jeep."
Knowledgeable - But Caustic

With regards to an 05 vs 06 ECM, I think there are other considerations.
Such as the 06 having 4 ABS sensors and traction control. Where the 05 has only 3 ABS sensors and no traction control.

But as far as the SKIM module is concerned, I believe it can be defeated.
AFAIK, the key identification only occurs in the SKIM module.
If the SKIM module is happy with the key then it tells the ECM to allow the engine to keep running. If it not, it tells the ECM to shut the engine down within 2-3 seconds.
So the key ID parameters are not stored in the ECM.
The ECM is programmed to listen for the commands from the SKIM and that part cannot be undone. But there are workarounds already built into the system that allow the engine to started and run in emergency situations.
If that workaround can be exploited then a properly programmed key is not necessary.
I did a search and found one possible solution but it's not convenient.

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U.S. Army Retired

Yes, and all the VSS ties into the airbag computer, not the Bosch ECU. Bosch ECU reads speed on canbus. Though this may be related to other compatibility issues.



I have a matched ECU, SKIM, and KEY from a 2005 in a 2006. These three items together are required to get the engine to start and run for longer than 3 seconds.

If I take the SKIM and KEY from the 2006 which match the vehicle, the ECU will not recognize them and shut off after 3 seconds.

I cannot use any combination of vehicle key/donor SKIM other than the above. So yes, the ECU most definitely is looking to read a key or PIN from a particular SKIM.

_________________
http://www.Colorado4Wheel.com
"Its not about what you can DO with your Jeep, its about where you can GO with your Jeep."
Knowledgeable - But Caustic

Yes the ECU definitely stores the required code that the SKIM will send to it everytime....not sure where this code is stored!
It is not a case of the SKIM Module sending an "I am happy with the code" message to the ECU.

I saw one post that claimed that a Dealer could program the ECU to think that no SKIM module is installed...you remove the the SKIM module and it should work but I have my doubts that this will work... although the SKIS system was not standard on all KJs so the ECU would not have been programmed on those Jeeps to await a code from the SKIM module.

We can of course jumper out the ASD relay but all that does is send acknowledgement to the ECU that it..the ASD relay...has energized....if the ECU in the meantime has not received a valid SKIM code it will not fire up the injectors!

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2002 Export CRD 2.5 Sport

I had some luck tonight, it seems that I got the ecu to start off of the vehicle key. The vehicle pin was necessary and then under the vtss/skim menu there was a Bosch ecm replaced option. I followed that menu and the ecm seems to learn the vin from the skim unit.

The skim unit also had an option for skin replaced. I wonder if I could have gone the other direction and learned a used skim to the vehicle ecu.

I'm still having some other issues that may be related to using an 05 ecu in an 06.

_________________
http://www.Colorado4Wheel.com
"Its not about what you can DO with your Jeep, its about where you can GO with your Jeep."
Knowledgeable - But Caustic

I did find out recently that MPPS does not flash the entire tune. I was playing around with some stuff and noticed that any changed prior to a certain address do not change once I flash a tune and then read it back to verify it. In fact, probably 90% of the hex addresses in the tune will likely not flash without a more powerful programmer.

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2006 CRD - GTB2056 turbo by Dieselguy86, Eco Trans Tune, Lift Pump, Week's, HDS Tstat, Racor Filter, ARP's, OME 790's+Top Plate, JBA 2.5", JBA UCA, Moab's+265/75R16, ARB Bull Bar, 4.10's, TrueTracs

Interesting.

I have the bin file from before and after the VIN reprogramming from the DRBIII. I should do a comparison and see if the vin information was written somewhere in it.

Then the question is if the MPPS keeps you from writing that information to save your own skin.

_________________
http://www.Colorado4Wheel.com
"Its not about what you can DO with your Jeep, its about where you can GO with your Jeep."
Knowledgeable - But Caustic

Comparing the ECU pinouts between the 2005 and 2006 models they seem to be identical.

The 2005 does interrupt some of the lines going to the ECU by having the FCM in the way but in theory the FCM has no drivers inside so should not be making any changes to the signals....what goes in to the FCM must be the same as what comes out and then proceeds to the ECM.

Must be a programming issue somewhere?

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2002 Export CRD 2.5 Sport

Agreed, both pinouts are the same between the 05 and 06, and the engine harness its self is the same.

The big difference between them is the Front Control Module or Gateway.

The FCM or Gateway as its referred to both ways in the 05 manual, takes a few signals and broadcasts them on the PCI and CAN bus.

They are:

Engine Oil Pressure
Water In Fuel
A/C Pressure
Fused ASD Relay output
Gen Field Control
Fuel Level Sensor

And supply voltages and ground.

Now ideally it doesn't matter where these things are on the bus. The module takes it out and there is a fixed address per the CANBUS automotive spec and it puts the data there.

However there are some other differences on the 06 related to the traction control/esp. These may require the software rev from an 06 ECU.

I don't think AC pressure is currently being read correctly by the ECU from CANBUS with the 05 ECU in the 06. If this is an obvious issue then there may be more that I cannot see.

More investigation is required, but this is also a good learning opportunity for me and the community.

_________________
http://www.Colorado4Wheel.com
"Its not about what you can DO with your Jeep, its about where you can GO with your Jeep."
Knowledgeable - But Caustic