Code 24 is a vehicle speed signal sensor fault, the sensor most likely does not provide a useable signal until about 25 MPH, when the computer doesn't see any signal after that speed it turns on the light. Make sense?

Hi, as I told you in the lounge the Rodeo can also be in Limp mode. When the engine warning light comes on this car goes in limp mode. Limp mode is a safe mode where the car control module limits engine to 1500rpm, and consequently speed to about 20/30mph.
Depending on the problem you may be able to reset the car from limp mode disconnecting battery cable for two minutes (ensure you have stereo anti theft code if needed). However this is not a good solution, since if warning light and limp mode are there , that means that there is a problem.
I suggest driving to the nearest garage and having the car computer module scanned to get the fault codes that can explain what is wrong with your car.