97 mazda protege....P1195 and P0400

This is on a 97 Mazda Protege SE, 5sp, 1.5L.

I have 2 codes, P1195 and P0400. I have had the P0400 for a little while (it comes and goes for some reason), but just today i put my scanner on again and there was also the P1195. The whole reason for putting the scanner on today was to verify the P0400 again and to erase it to see if it comes back.....i did a couple things with the EGR boost circuit and was hoping it would do the trick. Normally the after erasing the 0400 takes a while to set again, but the light came on in traffic almost right away....it was the 1195. I reset again and when on the highway to work it never set....as soon as i got off and in stop and go again the 1195 set again.

What i have done so far (for the original 0400):
- checked all vacuum lines associated with the EGR system (ok)
- checked EGR valve for proper resistance as per specs (ok)
- checked EGR boost sensor harness for proper voltage readings with key on as per specs (ok)
- checked EGR boost solenoid valve air flow when not energized (ok). Couldn't find wire at the time to apply voltage and see if air came out the other port.
- cleaned the contacts for the solenoid valve and harness as they were heavily corroded....was hoping that was the problem, but i guess not!

My vacuum pump is screwed so i couldn't apply vacuum to the boost sensor to check for changing voltage yet.

One other thing i have noticed is that when the car is cold and you start it, it revs up high initially for about 1 second and then drops down.....kind of like if there were a vacuum leak. Not when warn though and no other symptoms of a leak (ie stalling etc).

For the 1195 code though i am confused. My scanner said something like "Baro circuit malfunction" but in searching on the net i have also found (all related to Mazdas, not neciessarily proteges) "fuel air metering"; "SCP HBCC Failed to Initialize"; "boost/map sensor circuit malfunction "; and on this site under Mazda "EGR Boost Sensor Circuit". How do i even know which it is supposed to be and why are there so many variants?

any help would be appreciated,

thanks.

anyone?

Lots of egr issues on mazda's! i think you need to either try replacing the egr vlave or get it to shop for diagnosis.

First of all, I have no idea what you're referring to when you say "EGR boost valve". It's a nonexistent part. THere is no such thing. If youre vehicle is turbocharged than you're referrring to the BOV or blow off valve, which has nothing to do with the EGR. Re post . `

This is on a 1997 Mazda Protege with a 1.5 liter engine automatic trans.
I replaced the ECM two days ago on this car. The old one gave some strange
voltage readings at the harness ends of many of the sensors. After tracing the wires, checking for continuity, shorts, opens, and sensor operations, I decided to replace the ECM. It was a good call and now the Mazda runs!!!
I checked the codes in the system and found P1195, Fuel and air metering fault. In one post, someone said it would be a EGR Boost Sensor problem.

I checked for vacuum at the solenoid for the Boost Sensor, OK. I checked the ground/return wire (black/red) for continuity to the TPS and the engine processor, OK. I checked the grey/red wire at three sensors for the 5 volt reference, that was OK also. I checked the vacuum solenoid to the EGR boost sensor with power and ground circuit. The solenoid clicked as I did this. So I am assuming it works! The ohms for the solenoid were 43 ohms.

Any ideas on what this can be?

Still likely a problem with the solenoid circuit or the valve itself! Are you sure you have the correct pcm!

"EGR Boost Sensor" not valve....and yes, it is a valid part. All the docs refer to it and it even says it right on the sensor. I would post a pic if i could.

Update:

A while back i did more....tested the boost solenoid by putting power to it and it clicked and also changd the airflow through the ports, so it's ok. I put a vacuum pump to the boost sensor and voltage increased with vacuum as per spec, so it's ok.

I then read about the port on the back of the manifold being a problem with these cars so, due to tight access, decided to take the manifold off and clean out the ports good. The 400 code seemed to disappear and only the 1195 was left. A couple weeks later I then cleaned off all the goop (sil-glyde for spark plug boots) that i put on the boost solenoid contacts wondering if that really was dielectric grease....and sure enough, no more 1195 now. that lasted for about 3 days and now the light is back on with 400!

The EGR valve coils seem to test ok but i was thinking maybe grab one from the wreckers just to see?

Any thoughts?

I'd use a new part but that's just me!

You can post a pic. Just snap a pic and then post it.

At $350-400 for a new one, that is an aweful expensive guessthat i am not keen on unless i know for sure (especially when it "tests" ok).

Well if it "tests" okay now then I guess it wouldn't be intemittently failling! Have you checked for any tsbs or recalls from mazda for this! Like I said egr problems are common on mazda

actually i did some searching today again for info on code p0400 and found 2 tsbs that can set it. I forgot the sheets at work though....i think one was to do with the boost sensor maybe and the other a sticking egr valve i think, so ya never know!

One thing that seemed to come up over and over was the intake port to the boost sensor (solenoid actually) and then the port going up to the TB getting plugged. But i took off the intake and cleaned those pretty good. However the one article said two ports behind the TB and i thought i remember only one, so i may have to check that again as well.

Anytime anyone wants to explain how this EGR boost sensor works, Im still waiting. Otherwise this thread is going nowhere fast.