Chrysler Grand Voyager P0731 and P0792 Error Codes After Gearbox Replacement

Hi, I own a Chrysler Grand Voyager (European model, equivalent to the Town & Country) and recently had my gearbox replaced due to mechanical failure. Two weeks after the replacement, I started experiencing an issue: while driving slowly in the city at very low speeds, when I pressed the throttle, the transmission failed to engage properly. The car would stall or not shift, but once I stopped and restarted, it functioned normally. I took the vehicle to the official dealership, where they diagnosed P0731 and P0-than 2 error codes. They indicated this could be an 'occasional failure' and advised me not to worry. However, one week later (this morning), the same symptoms occurred again—exactly in the first five minutes of driving. I haven't yet taken it to a specialist for further diagnostics, but I suspect the issue may be related to cold-weather performance or a faulty component that behaves poorly when the engine and transmission are cold. The fact that it happens consistently during initial operation after startup raises concerns about underlying mechanical or sensor-related faults. Any insights or suggestions on how to diagnose or fix this would be greatly appreciated. Best regards, [User Name]