For those who have issues with your gps, you need to verify it urself by trying out this method in order to know what caused the problem.

1st,
Try change different ur telco from your current telco you are using right now.
Example; change from u mobile to maxis or digi. You can just borrow ir friend's sim card and straight away test drive using waze or gmaps. Don't forget to turn on ur data. Check if problem is solved by using different telco.

2nd,
Check your smartphone's network spec. Make sure your phone's bandwith supports your network/telco provider. For example, certain smartphones doesn't support certain network. Especially imported phones. If so, then you have no choice but to upgrade or change your phone.

3rd,
There are certain smartphone gps degrades when it's updated. Example android update from marshmallow to lollipop. You can try google it out for any reported case regarding gps issues after updating the OS. If possible, you can try downgrading your android yourself or sending it to someone you can rely or even a servise shop.

You can also test your gps by simple turn on both gps and data, search for a location you would like to test (at least 10km) when it's locked, start driving, if your gps looses signal, turn off your data & check if the gps could lock afterwards or still loose its signal.

Hope this could help you guys out a little.

Jimra.