Modifying your vehicle using OBD2 apps can be a rewarding experience, allowing for personalized settings and features. However, it’s crucial to understand the limitations and potential risks involved, especially when using specific apps with particular car models. One user’s experience with the JScan OBD2 app and a Jeep Patriot serves as a cautionary tale for those considering similar modifications, particularly concerning tire size adjustments and Daytime Running Light (DRL) alterations.
This user encountered significant issues after attempting to change tire size and DRL settings using the JScan app on their Jeep Patriot. The modifications led to the dreaded engine light illuminating on the dashboard, and the vehicle entering limp mode. Limp mode, a safety feature designed to prevent further engine damage, severely restricts engine power and vehicle speed, making driving hazardous and inconvenient. The error code P0610, relating to the TRANS CONTROL system, was identified as the culprit behind the limp mode activation.
Troubleshooting the issue required a series of steps to reset the vehicle’s computer system. The process involved disconnecting the battery and, crucially, draining any residual electrical charge by connecting the disconnected battery cables together. This procedure, often referred to as a “hard reset,” helps to clear volatile memory in the car’s computer modules. After reconnecting the battery, the user cycled the ignition and allowed the engine to idle, giving the system time to relearn its parameters. Subsequently, using the JScan app, the user meticulously reverted all modified settings back to their original configurations. An advanced scan and code clearing using the JScan app’s functionality were performed to eliminate the error codes.
Despite these efforts, while the P0610 code and limp mode were resolved, new codes emerged: B1634, B1630, and B1638. These codes pointed to issues within the high beam control circuit of the front lighting system, indicating that the DRL modifications had potentially caused further problems. Although the engine light eventually extinguished and the car returned to normal driving operation, the user was left with persistent headlight-related error codes and unresolved issues with high beam functionality when low beams were activated.
Contacting the JScan app manufacturer provided a crucial insight: the app reportedly does not handle tire size changes effectively on Jeep Patriot models. This suggests a potential compatibility issue or limitation within the app’s programming for this specific vehicle. The user also experimented with enabling HID headlights and other settings within JScan, but these attempts consistently resulted in the reappearance of the engine light and limp mode, reinforcing the app’s instability with certain modifications on this particular vehicle.
Further complicating the situation, the user’s Jeep Patriot is equipped with aftermarket HID projector headlights wired through relays. This custom setup, where the headlight wires trigger relays to power the HID circuit, might be misinterpreted by the car’s computer system. The computer could be detecting the altered electrical load or signal from the modified headlight circuit, leading to the erroneous codes and system malfunctions.
Considering alternative OBD2 tools, the user expressed interest in trying the Appcar Diagfca app. However, the uncertainty remains whether this alternative app would successfully handle tire size and DRL changes on the Jeep Patriot without encountering similar issues. This experience underscores the importance of researching compatibility and user feedback before attempting vehicle modifications with OBD2 apps. It also highlights that while OBD2 tools offer powerful customization options, they are not universally compatible or foolproof, and can potentially lead to unintended consequences if used improperly or with unsupported vehicle configurations. Caution and thorough research are paramount when using OBD2 apps for vehicle modifications.
