尽量 means do the best he/she can(having the ability to do something but only trying to find the will to do it). For example, "我尽量少说话。" ("I'll try to speak less", you are able to decide how much you speak but you only try to speak less) 尽力 means do the best he/she can(not having the ability to ensure it but try one's best to work on it) For example, "我尽力在下周一前把这个项目做完。"("I'll try my best to finish this project by next Monday", you don't have the ability to ensure it, but you'll work on it) 尽可能 means as much as possible. If you are not sure when you should use 尽量 or 尽力, then use 尽可能 to save yourself some trouble. Though nowadays 尽量 and 尽力 seem a bit interchangeable and people generally don't bother to distinguish them. Still there is a difference when talking to your Chinese boss(if you have one, perhaps in the future), with 尽量 you sound much lazier but with 尽力 you sound much more determined.

尽量是力求在一定范围内达到最大限度 尽力是竭尽自己全部的力量，竭尽全力。 尽可能可以和尽量互换，基本差不多意思。 希望对你有帮助，不明白欢迎再问.

你好！Eduardo Baptista， 很高兴再次看到你的问题，你学习很努力！ 这三个词有一些细微的区别，区别如下： 【尽量】有2种用法： 一种是强调：to the best of one's ability。比如：我虽无法做得十全十美，但会尽量小心，减少错误。 另一种是强调：to the full 比如：对病人的合理要求，医院尽量给予满足。 【尽可能】：the whole way 比如：我们要尽量减少额外开支。 【尽力】：strive 竭尽全力，比如：孩子的病我知道你已经尽力了，能做的都做了，你也不要自责了。 希望对你有所帮助，欢迎大家讨论补充~