pcmhacking.net

Tazzi wrote:I have been approached a few times about this, asking about resetting SKIM on chrysler/Jeep (FCA) engine computers.
For those that don't know what that is, SKIM (SENTRY KEY IMMOBILIZER MODULE) is the security system of the vehicle. The SKIM is its own module, but the ECM looks for a pass or go message that occurs from the SKIM system which is why the industry standard seems to the ECM SKIM reset (Basically ECM security reset).
From what I have read, the J2534 toolbox by drewtech does the older stuff but none of the newer (GPEC3 ect).

I have only found a couple places indicating selling software, one of which has a terrible reputation and has scammed multiple people with incomplete software, or stuff and just does not work

It appears people use the wording SKIM reset or SKIM removal. Personally I would think its two different things but it appears to be the same. Once the SKIM is reset in the ECU, effectively it has cleared the old security information (Back to new ecu state) so the ECU is ready for new security information. By design of the SKIM system, if the actual SKIM module is disconnected and the ECU is then fitted, this keeps the ECU in a non security state thus allowing the vehicle to start, but if that SKIM module is fitted again, the ECU detects the security and will activate its SKIM security internally.

Now thats been cleared up, there appears to be a couple methods to achieve this reset :
1) Use factory replacement methods which appears to require a PIN (not well documented).
2) Read security flash (tuning style) and write back in a fresh ecu section (VIN writing required after this).


Here is a copy paste of the actual replacement procedure:

Record the flash part number in the original Powertrain Control Module (PCM).
Have the vehicle Personal Identification Number (PIN) available.
Connect a battery charger to the vehicle.
Connect the diagnostic scan tool.
Position the ignition to the RUN.
Manually enter the Vehicle Identification Number (VIN) in diagnostic scan tool to identify what vehicle you are working on.
When the diagnostic scan tool successfully identifies the vehicle, locate the correct flash and flash the PCM software. Follow the diagnostic scan tool prompts. Position the ignition off for 90 seconds then cycle the ignition as directed.
Perform the “PCM Replaced” routine in “Misc Functions” menu under the Body Control Module (BCM).
Perform the “ Proxy Configuration Alignment ” located under the Guided Diagnostics menu in the activities section of the left margin. This routine will copy the PROXI into the PCM and write the PCM VIN. Manually enter the VIN into the PCM using the “Check PCM VIN” misc function under PCM.
Select the PCM view and then select the “ Misc Functions ” menu.
In the PCM “ Misc Functions ” menu, select and run the “ Learn ETC ” routine. This routine is necessary to learn the throttle position voltages and the accelerator pedal position. Follow the prompts shown on the diagnostic scan tool.
In the PCM “ Misc Functions ” menu, perform the “ Cruise Control Learn ” routine. Follow the prompts shown on the diagnostic scan tool.
Module programming is now complete.

Its interesting it says you require the PIN, but none of the steps actually indicate it. Further readings indicate that its appears to be a "Yes or No" message sent to the ECM to tell it to start along with a VIN. So if the VIN is correct, vehicle should start.

What leads me to believing that is the below statement:

Theory of Operation
The Powertrain Control Module (PCM) stores a copy of the vehicle’s module build configuration in its EEPROM. If the stored information in the PCM does not match the information sent over by the Body Control Module (BCM) of what modules are active on the Controlled Area Network (CAN) Bus, the DTC will set.
Set Conditions:
The vehicle’s topology does not match the original factory programming.This can be from a module being added, subtracted, or replaced without performing a proxi alignment procedure.
This DTC can set if the PCM was replaced and the VIN was not programed before the proxi alignment procedure was performed.

With all this said, has anyone had experience with using a used GPEC3 ECU (Chrysler 200) and fitting to a vehicle?