Sorry not to answer sooner but kept forgetting to look up code 24 in the workshop manual at work. Anyway it is shift motor fault, or wires to it. I would check everything is clean and dry again, some insulation may have shorted across when wet and now be tracking. I have known it to be false readings though, as the fault code system seems to rely on ecu sending voltage to motor, and angle sensor detecting movement. If it doesn't, it fault codes, but some angle sensor faults mean they don't send a signal back to motor.