Chrysler ECUs utilize various communication protocols, including SCI, PCI, 11-bit CAN bus, and even 29-bit CAN bus. While SCI and PCI are less common, understanding their low-level logic is crucial for module flashing. Determining which Engine Control Modules (ECMs) specifically use 11-bit versus 29-bit CAN bus remains challenging due to limited online resources. The difference likely lies between GPEC2A and GPEC2 ECM types, but concrete information is scarce. Furthermore, acquiring new Chrysler ECUs proves difficult, with limited availability and inflated prices.
Investigating the Security Key Immobilizer Module (SKIM) reveals that its status can be checked via a request, suggesting a Diagnostic Identification (DID) query verifying a specific value. An inactive state is likely indicated by a value of FF or 00. Another critical aspect is the SRI (Software Reset Indicator or Service Reminder Indicator), representing the odometer reading within the ECU. This value, retrievable through a DID request, must match the instrument cluster reading for the odometer to function correctly and for successful engine computer replacements.
Chrysler ECUs also employ internal bootloaders for read/write operations. However, many post-2013 models are reportedly “locked,” preventing custom tuning. The nature of this lock remains unclear. While dealerships can perform updates, it’s speculated that encryption or digital signatures might be involved, similar to GM vehicles. Unlocking these ECUs, potentially through bootloader modification or replacement with an older, unprotected version, is a necessary step for custom tuning. However, concrete information on these procedures is scarce online.
Reports indicate that some online unlocking services render ECUs incompatible with commercial tuning software like HP Tuners. This suggests that the bootloader code may be custom-edited for each specific commercial solution, potentially creating compatibility issues. This highlights the complexity and challenges associated with Chrysler Specific Scan Tool Module Flashing and the need for reliable information and tools.
