Okay, I have an CEL for P1400, I finally found out what the code is, but knowing that doesn't help me. It is "Manifold Differential Pressure Sensor circuit".

What the hell does that mean and what do I need to do to fix it?
Hopefully someone on here knows...

 

MAP sensor, located on top of your intake manifold.

 

that makes sense

 

its not a map sensor, and it doesnt affect your tune or how your car runs, its only for emissions....or at least im pretty sure it is.

 

So it doesn't do anything?
So how do I get the CEL to stay off when I delete the code, because it keeps coming back.

 

Replace your map sensor.

 

MAP=Manifold Absolute Pressure=Referenced to vacuum
MDP=Manifold Differential Pressure=Referenced to atmospheric
No matter what you call it, it serves the same function, it is used by the ECU to calculate engine load, which the ECU uses for a few things, like which timing map to use and when to open the EGR valve as well as open/closed loop.

I read that it happened to some people that go from a 7 bolt to a 6 bolt. The MAP on the intake manifold is to check operation of the EGR system and a MAS to meter airflow

 

This is the manifold differential pressure sensor, also sometimes incorrectly referred to as a manifold absolute pressure (MAP) sensor.
The MDP sensor measures the amount of vacuum in the intake manifold. It does not do this to measure the amount of air entering the engine. The MDP sensor measurement is instead used to monitor that the exhaust gas recirculation (EGR) emissions control system is working correctly. 1G cars used a temperature probe for this, while 2G cars use the MDP sensor.

 

you should just replace it though. its the only way to make it stop throwing the code, unless you get dsmlink.