Hello. First time poster here. I recently was given a 2003 Lancer ES 5spd. It came with the service engine soon light on. So i popped the hood and started inspecting to see if I could find anything. right away I noticed that it had one of those small breather filters on the breather tube that sticks out the right of the valve cover and where it was suppose to go in the 90deg elbow bfore the throttle body was completely open. So I assumed this was the cause.

I proceeded to scan the code with my Actron CP9145 and found out the code number and such, but it was manufacturer specific. Searched the database on the CD that comes with it and it says its: Manifold Differential Pressure Sensor circuit.

So i took out the little filter and routed a hose to where it's supposed to go. I erased the code and started the engine. Right away I noticed that the idle went down about 200rpm so i thought everything was fine. But 2 days later the light cam back on with the same code.

Anyone got any ideas before I take it to the dealership? The car is completely stock, cept for an Evolution type body kit minus the hood and grill.

 

you could check the MAP sensor on the intake manifold. its the only one on top. unbolt it and see if dirt got caught up in the sensor or in the pinhole on the IM to the sensor.

 

I had to replace one (MAP), mounted on top of the intake manifold.
I think its part # MD305600. I paid $92.44 for it.

 

I'm also experiencing the same issue. I have a 2003 Mitsubishi Evo GSR 8 and I've been throwing a P1400 code. Did you buy the part and see if it clears the code? I'm almost tempted to buy this too and try it out as I'm tired of clearing the code.

 

this code is being thrown on my 02 lancer oz ralled edt.
any ideas?