How do I fix this code P0123 for a Mazda Protege 2002?

SOURCE: what is code P1195 on 97 mazda protege?

That code is for the EGR boost sensor. It has an open or a short in one of the wires.

SOURCE: Timing Belt on 2002 Mazda Protege

every 90,000 to 100,000miles and yes it is strongly recomended to replace the water pump with it

SOURCE: where is the blower motor resistor on a 2002 mazda protege?

just remove the glove box and its right behind it just take the white pug out and the two phillips screws to remove the resistor out, replace with the new one and cool off!!!! Hope this helps

SOURCE: obd2 code p0300 on mazda protege 2002

Just had one of these with a maxima, the code is multiple random misfire, when a misfire occurs, to start is do the basics, replace the plugs, check fuel pressure, clean throttle body, and coolant is topped up. also I have seen if the O2 sensor is not working correctly is can cause a misfire, you will need a scan tool to look at what the O2 sensor is doing, o rby back probing the sensor (don't damage the O2 sensor wires). If it wires replace them as well, if it has coils they usually dont give that code if one fails, it will pinpoint that a certain coil if one fals.

SOURCE: code po705 mazda protege lx shaking rough start

The Code you refer to is P0705 Transmission Range Sensor Circuit malfunction (PRNDL Input). It is a possiblility that because this code is present, this sensor is malfunctioning. If it is malfunctioning, that means the engine needs to "guess" the value that this sensor is responsible for. In most cases when this happens, the engine will go for a value that ensures the car runs. The engine will not try to run smooth or efficently, it will only try to run. It is my guess that if you have the sensor checked and replaced, the problem might be fixed. Please let me know if this answers your question and please rate my response. Thank you

Testimonial: "that is good. where is the trasmission range sensor circuit located "