P0400 diagnostic

[karbon]

I'm running 0 emissions equipment. Never a CEL. I don't get what the problem is that people have with this. Don't unplug your solenoids!!!
I'm hooking EGR back up for winter. I want the extra ~40 miles per tank I lost back.

 

[1fast97gsx]

I'm running 0 emissions equipment. Never a CEL. I don't get what the problem is that people have with this. Don't unplug your solenoids!!!
I'm hooking EGR back up for winter. I want the extra ~40 miles per tank I lost back.

yea exactly ... as long as all the sensors are plugged in there shouldn't be a light

 

[44pirate]

as i have said many times.......removing the egr on a gen 2 ABSOLUTELY WILL GIVE YOU A CEL.....PERIOD!!!!! let this be a lesson to anybody that tells you otherwise, the way to get rid of the cel is hook the egr back up or go to a standalone system, or re-chip your ecu if you have a 95 ecu.............

I removed my EGR crap and never got a CEL.

 

[44pirate]

yea exactly ... as long as all the sensors are plugged in there shouldn't be a light

The MDP sensor which sat on the top of the 2g intake held on by 2 bolts, you still have to run a vacumn line to the nipple of the sensor. Run it off of the P port on the TB, T it in if you have to.

 

[1LE]

Heh, I get a light even with everything plugged in and working! Everything was unhooked when I got the car, so I checked/cleaned the EGR and reconnected. Still getting lights. Replaced the solenoids. Still getting lights. Replaced MDP and vacuum hoses. Still getting P0400.

 

[1fast97gsx]

Heh, I get a light even with everything plugged in and working! Everything was unhooked when I got the car, so I checked/cleaned the EGR and reconnected. Still getting lights. Replaced the solenoids. Still getting lights. Replaced MDP and vacuum hoses. Still getting P0400.

yep that's my exact reason for starting this post. I throw the code either way as well.

 

[Boiler2]

Just some additional information for everyone. I recently got a P1400 code which is "Manifold Differential Pressure Curcuit Malfunction" according to the shop manual. The manual goes on and says to check the wire harness to this sensor, check the sensor itself using a volt meter off prong 1 in the plug, and then replace the ECU. I know I do not have a faulty ECU. The manual says nothing about the EGR system as a possible cause to this nor does it say to check the EGR system.

I simply pulled off the MDP sensor, cleaned it out and the leads to it, put it back on, and so far have not gotten another code. It has been 2 days so it is early but I have put on about 100 miles. I also bought one at a junkyard as a spare for $20 which is a pretty good deal since new ones are ~$95.

I know your code is P0400 but people are talking about the MDP sensor in this post.

 

[CanadianTSi]

I don't see what the big deal is, my CEL has been on for 2+ years now, just learn to live with it.

 

[1LE]

I don't see what the big deal is, my CEL has been on for 2+ years now, just learn to live with it.

Pretty hard to pass e-check with the MIL on

 

[karbon]

Pretty hard to pass e-check with the MIL on

Move to Stark County like I did. No E-Check!

 

[boostcreep]

Just some additional information for everyone. I recently got a P1400 code which is "Manifold Differential Pressure Curcuit Malfunction" according to the shop manual. The manual goes on and says to check the wire harness to this sensor, check the sensor itself using a volt meter off prong 1 in the plug, and then replace the ECU. I know I do not have a faulty ECU. The manual says nothing about the EGR system as a possible cause to this nor does it say to check the EGR system.

I simply pulled off the MDP sensor, cleaned it out and the leads to it, put it back on, and so far have not gotten another code. It has been 2 days so it is early but I have put on about 100 miles. I also bought one at a junkyard as a spare for $20 which is a pretty good deal since new ones are ~$95.

I know your code is P0400 but people are talking about the MDP sensor in this post.

Does anyone have a suggestion for running a vacuum line to the nipple end of the sensor its has odd dimensions and anyone who's solved this issue please pass some knowledge this way...

 

[1LE]

Does anyone have a suggestion for running a vacuum line to the nipple end of the sensor its has odd dimensions and anyone who's solved this issue please pass some knowledge this way...

The same 3.96mm vacuum hose that fits most of the other lines will fit on the MDP. Secure it with some RTV (and a ziptie as well if you're paranoid)

 

[boostcreep]

The same 3.96mm vacuum hose that fits most of the other lines will fit on the MDP. Secure it with some RTV (and a ziptie as well if you're paranoid)

I'm running high boost. The RTV will not keep that on. Is this something you've done?

 

[1LE]

I'm running high boost. The RTV will not keep that on. Is this something you've done?

Yes. I'm currently on my 2nd MDP with the hose attached this way. Never had any problems with it staying attached. How much boost are you running?

 

[1fast97gsx]

I just zip tied all my lines ... never had a problem.

 

[boostcreep]

Yes. I'm currently on my 2nd MDP with the hose attached this way. Never had any problems with it staying attached. How much boost are you running?

18 psi. on the street sometimes as high as 20 psi....

 

[1fast97gsx]

that's not high boost. I was doing 24 on the street ... then only up from there with race gas. 75% of decently modded dsms have run over 20 psi with no problems....

 

[boostcreep]

I spiked there (24psi) a few times. But I tend to blow smoke above 19 psi. I'm still trying to figure that one out. I'm hoping it's just the seals on the EVO3. My motors only got 19K on it.

Emmanuel

 

[1LE]

18 psi. on the street sometimes as high as 20 psi....

I don't run that much boost anymore, but the previous owner had it up there 18+ with no problems blowing the glued on hose off the MDP. Look at your other vacuum hose fittings sometime, a lot of them are just simple slip fit (no barb) and they'll generally hold into the low 20's with nothing else helping (zipties help though)

 

[housegsx]

1fast97gsx or 1LE, what did you do to solve this? I have a CEL and am throwing the P0400 code. This happened right after I did the Taboo vacuum line change. All of my solenoids are left plugged in and without vacuum lines attached. I need to get this resolved to pass emissions.
What if I just hook the EGR valve back to the EGR solenoid and the manifold as it was before, but no T-ing off to the EVAP canister as I do not have it anymore.