Mazda World Forum banner
41 - 49 of 49 Posts

·
Registered
Joined
·
26 Posts
Well, knock on wood, I'm hoping I've finally licked it....

I've had a P0400 anfd P0404 code popping up for a long, long time. I had been scared away from the EGR valve itself, thinking it was hard to get to. (It's not!!)

I've tried most of the other solutions in this forum without any success. But finally I decided to do a dry run at a u-pull-it yard, and over a few weeks pulled and bought 4 different used egr valves. Took them apart, got to know them. I'm pretty good at pulling them now!

I would say the most surprising thing I learned was that some EGR valves have coolant lines running through them, and some don't. This was confirmed in another post above here.

So I go to pull my own, and I can't get the darn bolt to budge on the driver side. Smartly, I brought it to my favorite local shop. Took them 3 hours and $200 to break and then drill/tap that bolt out. But at least my $8 replacement egr valve has kept the CEL from popping on (so far).

If that fixed it, then at $208 I'm still way ahead of a lot of others. And I'm smarter now than I used to be!
 

·
Registered
Joined
·
53 Posts
The EGR valve does not need to be cleaned. My 140K miles EGR valve looks reasonably dry and clean. However, you can remove the EGR valve to check that the air can flow from the EGR ports to the EGR valve easily. You can use compressed air blower to check air passage by blowing into the EGR port. The air will be blown back to the opened mounting holding the EGR valve.

II) To remove the EGR valve easily, do:
1. Remove the electrical wire and mounting bracket on top of the EGR valve to get access.
2. Remove the vacuum hose on top of the EGR valve.
3. Remove the EGR valve mounting bolts.
4. Remove the EGR hose feeding into the EGR valve. This hose is dotted red.
5. Remove the water hose feeding into the EGR valve. This hose is
Thank you for a good recipe.
I suspect that if you find lot of crud and deposits in the air intake after the throttle body, the EGR valve and the passage from the EGR to the air intake downstream from the throttle body will also be dirty.
I believe in not touching something that's not broken. Since the throttle body is already off and there was lots of carbon build up there and in the EGR ports, I figure cleaning up the EGR is not a bad idea.
I have a 2001 Millenia 2.5. I have checked the EGR valve position sensor operation, by measuring its resistance with and without vacuum. The resistance is close to the specs. I have checked the EGR solenoid (vent) operation.
I have procured the EGR gasket and am going to remove the EGR and clean the valve and the EGR ports at both ends. I can see the two water hoses, and the vacuum line. The two EGR bolts can be removed easily too.
I don't see any EGR input hose. I know the EGR has to have two ports, an input port for exhaust gases to enter the EGR and an output port to send it to the incoming air just past the throttle body. It makes sense that there could be an input hose or output hose.
To me, it seems that there are no hoses for the exhaust gases. How does the gas enter and leave the EGR? Are there holes in the manifolds that align with the two (input and output) ports of the EGR valve or am I not looking hard enough. I looked and tried to feel with my had too, but I don't feel or see anything. In some cars there is a metal hose and pressure fitting screwed on to the EGR. How is on the 2001 Millenia?
 

·
Registered
Joined
·
53 Posts
The metal hose coming from the exhauat does not have to be disconnected. The EGR valve can be removed without touching it. The worst part was removing the coolant hoses.
Why does Mazda use this type of hose clamps? As suggested above by someone else, I will replace them with worm gear type clamps.
I was able to remove the coolant hose closer to the firewall with some difficulty, but couldn't undo the other coolant hose. So I I undid the two mounting bolts and once the EGR valve was free, I was able to remove the other coopant hose by turning the EGR valve back and forth, since everything else had already been disconected from the valve.
The valve itself needs to cleaning, but the passages do.
 

·
Registered
Joined
·
334 Posts
Hey i have the same issues. At first i was getting p0300 and my car would stumble and wanna stall but drive good. So all of a sudden one day i get a CEL for P0404 and since then my car would stumble and stall once i put it in drive or reverse. But it idle good, only stall when i put it in drive, and if i give it gas it doesn't stall when i drive

Zoning
 

·
Registered
Joined
·
2 Posts
(new-b) with P0400 on '02

Long-time reader, new member. Thanks to all out there sharing their expertise with those of us who have none.

Short version of long story...bought a '02 millenia about 5 years ago. immaculate records in great shape (little did I know...). Engine light has intermittently plagued me ever since (various durations and codes - sometimes going away on its own).

Most recent - P1521, P0400. swapped the two VRIS solenoids and watched the code change to 1522, so replaced the bad solenoid hoping both codes would go away. Only 1521 did. Based on all the help in this thread and other references, bravely removed and cleaned EGR valve and replaced gasket, cleaned throttle body (was dirty) and fussed with vacuum hoses, replacing a few links where felt like it would help. After reset, P0400 still came back

Based on the milleniatech info posted somewhere, p0400 could be:
Map sensor, map solenoid
EGR valve/gasket, EGR vent solenoid, EGR vacuum solenoid
ECU

Auuuugghhhh!!!
I have limited confidence and limited tools but would sure like to lick this. Is there a likely sequence of failure to the components above or at least a sequence of things a novice could try to isolate the defective part/function?

I have found the Map sensor and solenoid (pretty easy to get to), the EGR vent and vacuum solenoids (less easy to get to). I took the map solenoid off today and applied voltage (9V battery) and got a click, suggesting it works.

My longer term dilemma is if I fix it do I keep it, or sell it before it happens again...

Thanks for enduring the long post. Any insights welcome.

Tim
 

·
Registered
Joined
·
3 Posts
Looks like i have these codes. i took the intake manifold off to see if there was alot of carbon build up. it was fully caked in black buildup but how much is to much and which is the best way to clean it without getting carbon down into the manifold ports?
 
41 - 49 of 49 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top