Serpentine Belt and Throttle Body Sensor

If you're referring to the throttle position sensor, they have a very low failure rate, and it isn't related to the belt. You repair it by replacing it. What symptoms or problems led you to the sensor?

The TPS has almost nothing to do with how much fuel goes into the engine. Now you're mentioning smoking too. Please start at the beginning and include all the details. The Check Engine light tells us there is a diagnostic fault code stored in it. Have you read that code? What was smoking? Out the tail pipe? The new belt? Oil on the engine, etc.

Dandy. The first thing you must be aware of is diagnostic fault codes never say to replace parts or that they're bad. They only indicate the circuit that needs further diagnosis. About half of the time the sensor referenced in a code is actually defective, but the other half of the time, especially when there's two related codes, it's a wiring problem related to them. In this case, both sensors share a common 5.0 volt feed and a common ground wire. A break in either wire would trigger both codes. It's much more likely a shredded serpentine belt flung a piece around that cut a wire. Those sensors are pretty tough, and they're not close to the belt, so testing the wiring is the next step.

Unplug either sensor and measure the three voltages on the three wires with the ignition switch on. (That alone will also set a fault code). You should find 5.0 volts on the feed wire, 0.2 volts on the ground wire, and 5.0 volts on the signal wire in the middle. That signal wire voltage should drop to around 0.5 volts if you plug the sensor back in and back-probe through the rubber seal around the wire.