After replacing two sensors, My truck now throws a 14 code, which is MAP sensor voltage too low. What does that mean? How do I fix it? Could it just be a bad map sensor or what? Sorry for all the questions, but I really want to get this thing goin. It wont idle for the first minute or so, and then after that its alright. I can also see the battery voltage guage having larger fluctuations when its about to stall (When first started). Can somebody shed some light???


THANKS!!!

 

I could be wrong, but I believe the MAP sensor and other similar sensors use a voltage regulator to send the signals. There are two ways sensors can send an electrical signal, either through voltage changes or resistance changes. Again, I could be wrong, but I believe the sensor voltage too low means its reading outside the "normal" range. That can either be because its a bad sensor or the manifold is not at the required pressure. Start by changing that sensor and go from there.

As for the voltage gauge, that would be because if the motor is running at an excessivly low RPM (assuming by "won't idle" you mean low idle), it can't spin the alt fast enough to produce it's typical 14.4 volts. If the alternator gets below 12.8 volts (or whatever the battery is typically charged to), power will start coming from the battery rather than the alternator.

This is all just my understanding of the the system works, feel free to correct me.