Temperature sensors never go bad, it's either the SMC or depending on machines a mosfet gone bad.It's fixable by a Pro but of course not on a do it yourself basis. You can disable the temperature check and relevant throttling by removing the kext file relevant to your machine but then you have to use a third party utility to engage and regulate fans in order not to overheat and burn up your CPU.
It requires some time and work, but it's a good trade-in to avoid a costly repair or a new logic board. Disabling the kext differs from version to version of the OS and not knowing what you're running I'd recommend looking on the net for "IOPlatformPluginFamily.kext", with a little patience you'll find the right solution for your Mac Os version.