P0403 - EGR circuit problem

Hello everyone

I've recently (just yesterday) just installed an upgraded TMIC (CP-E) for the 3 MPS and performed the coolant bypass mod.

After installing I drove it 20 or so minutes on the saturday night and nothing had come up as a CEL until starting car up for a drive just now (sunday night) for another 20mins. The CEL appeared straight away and the AP diagnosed it as a P0403 - EGR control circuit problem. I was only monitoring boost pressure (spiking to 21.7 psi) and that seems to be in check so am I right in presuming my pipes were tightened down properly? (i was conscious of tightening down all piping properly so triple checked when i installed the TMIC).

My other thought was potentially it may have been the coolant bypass mod that caused the CEL? I did lose some coolant whilst performing the mod, but i didn't think i lost enough to cause a problem? I also haven't checked my coolant levels knowing i did lose some...i will check this tomorrow evening. According to the instructions, I plugged the bottom inlet nipple (the one closer to the front of the car) with the one i removed from the top inlet nipple and plugged the top nipple with a snug rubber inlet thingy. I did the mod according to instructions at this website: Mazdaspeed 3 Throttle Body Coolant Bypass DIY | Mazdaspeed3 Extreme Performance

Anyway, right at the end of the drive i started to hear this fan noise near the front radiator (is it a radiator? it looks like a stock FMIC..?) like it was struggling / starving for air. The 'fan' continued to run after i turned off the engine for a little bit (5 seconds or so).

Has anyone experienced this CEL and/or this fan noise after installing a TMIC and/or a coolant bypass mod? Not quite comfortable with the fan noise it's producing 15mins into driving. Anyone know where potentially the fault could be?

If it helps, i've also got engine upgrades on the following:
downpipe
cat back
HPFP
SRI and TIP
TMIC + coolant bypass + ITV22s (did these all in one go)
EGR mod
bypass value
stage 2 AP tune for DP+SRI+TIP+HPFP+IC

Cheers
mps3er

---EDIT---

Ok I was anxious to know what went wrong, so i went and checked the coolant levels and low and behold, there's absolutely no coolant left in the tank..oh oes....

So that definitely narrows it down to something going wrong in the coolant bypass mod. It all the coolant suppose to drain out after you perform this mod? If I fill up the coolant again, what's stopping it from draining all out again..?

Currently, both throttle body nipples that connect into piping have been blocked off (as above, the nipple closer to the front of the car is replaced by the piping in the other nipple, and that one is blocked off by a rubber stopper/cap)...the loose pipe is just zip tied to another random pipe so it doesn't go wandering about...

If the coolant is leaking somewhere, you could just fill up the coolant, leave overnight and see where its leaking from.

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Hmmm
I didn't unplug any radiator plugs. The only other thing I can think of is the rubber cap has fallen off from the nipple inlet going into the throttle body?
what's the directional flow of the coolant anyway? Does it come from the piping into the TB or the other way around...or have I got something completely wrong..:s

Its coming from the engine side into the TB and out back towards the engine. Losing the rubber cap on the throttle body wouldn't leak much at all. (Would be less than what's leaked when you first unplug the hose)

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Quote:

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Originally Posted by mps3er

Hmmm
I didn't unplug any radiator plugs. The only other thing I can think of is the rubber cap has fallen off from the nipple inlet going into the throttle body?
what's the directional flow of the coolant anyway? Does it come from the piping into the TB or the other way around...or have I got something completely wrong..:s

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So you did a coolant bypass and failed to check coolant levels after it, now above questions not even knowing where the coolant flows..amazed you still have an engine that starts.
Sorry if it sounds like im bein a dick but not checking levels on things etc after changing a mod that effects some sort of fluid is just..........

I don't see why one need to check the level as the bypass would only leak so little tiny bit of coolant, so i'm not surprised that he didn't check it after. However, the problem now is, the entire reservoir is gone......which is a mystery.

yeah that was my logic. very little was lost.

anyway, after doing some more searching, I think i have found where i went wrong...i'm going to be trying to connect the two coolant pipes together with a brass connector instead, then fill coolant reservoir and monitor the levels. if this fixes it, then the instructions i went off were a bit misleading....

Did u used a plastic connector in the first place?

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nope. not according to the instructions...as i said i think the instructions were a bit misleading, especially the pictures..

anyway, after connecting the two coolant pipes up, i filled the reservoir back up with coolant yesterday and idled it for about 10mins and did a rev here and there. The level has seemed to remained. Unfortunately after driving it for a short while this morning, the reservoir seemed to have emptied itself out again T_T...however there was no coolant 'splutter' in the engine bay area so it appears the leak isn't coming from the pipe joins...

No idea where this possible leak is as I hadn't touched any other piping when doing the bypass...this is a complete mystery to me!! ><

If anyone knows of any other tips/places to look at that would be helpful. there is no clear sign of any leakage in and around the piping, radiator or the engine bay.

Will take it to a service on Monday if no diagnosis is imminent.. sigh*

The MPS 3 coolant overfill bottle has been known to leak , check it to make sure it isnt leaking or has any cracks.

i let a filled reservoir sit overnight and checking it the next morning, the levels were the same.. it's only when i go for a short drive that it decides to drain itself.

anyway, attached a couple of pics

pic of plugging the nipples into the throttle body photo 2.JPG
pic of the join of the coolant hoses..photo 1.JPG

on second inspection, it appears there is spluttering of coolant around the engine bay...perhaps the join is not airtight enough?....

Hmmm...can't tell much, but the connector used, is quite different from the one I used...

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Yeah , that almost looks like a check valve - you should just use a brass barbed fitting and use worm clamps not those tension clamps, they tend to leak.

This is what i used

http://farm6.staticflickr.com/5524/1...b7e5a39b_c.jpg

Still the tension clamps, but considered how the brass connector's slightly bigger than the actual hole size of the hose, its a pretty tight squeeze for any leak to happen

hey guys, an update - took the car in for a diagnosis and it turns out there was an air bubble stuck inside the cooling system. There was no actual leakage - they confirmed with a pressure check (tho i actually swapped out the original brass connector and fitted a straight thru barb) then did a complete flush and now everything's back to normal.

moral of the story is i guess, do a proper coolant system flush afterwards, or clamp down the coolant hoses before unhooking them from the TB so minimal/no air gets inside.

a cheap mod turned out to be rather exp..lol

anyway, thanks guys for helping anyway.

???? Don't see how a (or a few) air bubble can block the whole cooling system??? Thing is, didn't you say you only lose very little coolant when you do the initial install?? If yes, then how would some air bubble make the reservoir tank looked empty??

Suggest to monitor it abit longer and see...

drove it for a good 30mins and levels are good...yeah im not sure how the coolant escapes the system..should've asked while at the dealership..