Масло коробки по проводам затекло в разъём

Fluid travelling along a wire inside its insulation from a failed case connector seal into the module's connector. It is the same mechanism as oil ingress on the engine — capillary action along the conductor — and the destination can be a long way from the source.

Fluid in a connector does not short the circuit; it insulates it. So the fault is intermittent and resistive rather than a clean failure, and it worsens with temperature and vibration. Codes name solenoids and sensors that are perfectly healthy, and often several at once, because the fluid reaches every pin in the connector it fills.

The transmission's own case connector is the entry point, and its seal is the part that fails. Check the module end as well as the transmission end — fluid that has travelled the harness arrives at a connector nobody thought to open, and a module can be destroyed by it. Replacing the seal without cleaning or replacing the affected harness section leaves the fluid already in it, which is why this fault so often returns after an apparently correct repair.