Identify a component inside an RC car. Dual H Bridge?
The chip you are looking at is not just a H-bridge, it is also a RF (24 Mhz) receiver, command decoder, and motor control. The RF control can be anything, FM or AM modulation, and if you have a working remote, you should be able to capture the commands it is sending. Unfortunately it will take a "fancy equipment" to capture and decode, and it can't be done with "wet finger" such as a multi-meter. 

It will be cheaper just to replace the entire toy electronics with known H-bridge (or just with a standard motor controller shield) if you want to control the toy with Arduino.