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Discussion Starter #1 (Edited)
Hey everyone! I need help diagnosing the P2227 and P1487 codes that have been plaguing my '04 3.0 Mazda 6.

Here is the information that I found elsewhere and believe to be accurate about the codes:

P1487 - EGR boost sensor Solenoid valve circuit malfunction ON 2 CCM

P2227 - EGR boost sensor circuit performance problem ON 2 CCM


This seems to indicate a bad boost sensor? Well I recently replaced the boost sensor and I've still been battling the codes for about 250 miles. The car is running fine and my mileage has not changed noticeably.

What do I do next? The nearest Mazda dealership is an hour away and I would like to be able to sort this out on my own. However, I need to pass emissions by the end of the month.

Thanks!:)
 

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Sounds like the ECM doesn't think it works. We can dig up the ohms measurement for the solenoid or you can apply 12v to it while the engine is running at idle and the car should fall on its face (die/stumble). I would use a heavy test lamp at first (ground one side of valve, use test lamp from +12V to other side of the solenoid) just so you don't over current the solenoid. If it lights bright, go for the direct connections with very small gauge wire (like 18 - 22 gauge).

The other option is all the equipment is working but the EGR is plugged. Did you pull the tip out of the manifold? The ecm expects to see a vacuum difference when its active. If no change, it thinks, no worky....
Is this a Grocery getter idling around most of its life?
 

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Discussion Starter #3
I think I'm a little intimidated by the electrical checks so I'll try those second.

I would like to try checking the EGR Valve first.

Could you be more specific about pulling the tip out of the manifold?

This car commutes at highways speeds 4 days a week.

Thanks for the help!
 

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If you can get that big nut on the EGR pipe off, remove the EGR, then remove the 3 screws holding the nozzle into the intake manifold. From here you can inspect the down pipe, valve and nozzle.

if you have an ohm meter, measure the coil resistance of the solenoid. If its infinites, the coil driving the valve is bad. I'd guess its 150 to 50 ohms but need to find the spec. I might be less. Next, using small gauge wires power it up and listen for a click off and on with the car off. It should throw a tiny spark. very tiny. If nothing, a good sign its burned open.


The other option is to take off the manifold. Only takes about 25 min.
Here is what your looking for. Sorry - don't know who to give credit too for pic...
 

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To answer your question, the sensor is on the firewall, 3 pin conductor and the Solenoid is on the EGR pipe with 6 pins. Their name is nearly the same; EGR Boost Sensor vs EGR boost sensor Solenoid.

P2228 says if Terminal 34 of the ECM is 0.35V or less all the time it will be triggered.

EGR boost sensor failure
Open circuit between EGR Terminal C and PCM terminal 90
Open circuit between EGR Terminal A and PCM terminal 34
Short to GND circuit between EGR boost sensor Terminal A and PCM terminal 34.

EGR - PCM
A - 34
B - 91
C - 90
 

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Discussion Starter #7
Thanks again for your help, and explaining the differences between the sensor and the solenoid.

I found a DIY thread on removing and cleaning the EGR valve which I'm about to go try right now.

However, I'm still fairly confused on how to do the electrical checks, I have a nice multimeter but I'm not very experienced with it. I also don't have any test lamps.

If you could, (and you don't have to) I would appreciate dumbed down explanation for electrical morons like me. I just want to confirm is the solenoid does or does not work.
 

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Discussion Starter #9
OK, here is the latest update for everyone:

A couple days ago, I removed, cleaned, and modded the EGR valve, and I found a booger that seemed to be blocking the hole in the EGR Tube.

I was guessing that was the problem, however my CEL came back on last night but with only the P1487 code.

Car still runs fine, the mechanical part of the EGR valve operated smoothly, all pipes and tubes connected to the EGR valve and the EGR sensor were checked and are clear.

I haven't done any electrical tests because I don't really know how to, and I don't want to break anything.



Does this leave the EGR sensor solenoid not functioning as the only logical problem left?

Do I just replace the whole EGR assembly now?

Is the EGR Vacuum Solenoid something I should be looking into?
 

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As mentioned in pm I can take a little more time and see if I can highlight some steps. I would hold up on buying till you know the power and vacuum is there.
When is the last time it worked properly?
 

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Discussion Starter #11
I'll be out of town until the 26th, so I won't be able to work on it until then. However, my emissions test is due the 29th, so it will be crunch time when I get home.

CEL first came on about 2 months ago and I started working on it in the beginning of December.
 

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OK here is a test you can do with the EGR VALVE; P1487
Unplug the connector, It has 6 conductors, lets label them as follows. The key point being the two from the center C & D, to ALL other points is 20 ohms on the AJ. 12-16 ohms on the I4.
Looking into connector, take 4 measurements:
E-C-A
F-D-B


With your DMM short the test leads together in the Ohms mode and you should get a reading of 0 to 1 ohm. If higher (1 - 5 ohms) subtract this from your reading taken on the solenoid(s).

C -> E = 20 ohms
C -> A = 20 ohms
D -> F = 20 ohms
D -> B = 20 ohms
Below 15 ohms or above 25 ohms, its defective. Also inspect all pin for damage on the connector and trace the wires as far you can for damage.

If this test good, the 4 leads on the outer corners go to the ECM. The 2 in the center go the the "main relay" so it says. Oddly enough, there is a relay called main in my 06.



You could pull the relay and ohm between the contacts to see if the connection from the body harness to the EGR is intact. Should read less than a couple ohms.
WITH THE RELAY OUT and looking into to the connector: It has s T shape.

A - X - E
___C
___D

X is not populated. Check email... All I have time for now...
 

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Discussion Starter #13
Due to all of my flights being canceled for weather, I had time to test this today and here are the results:

C -> E = 25.2 ohms
C -> A = 25.2 ohms
D -> F = 25.4 ohms
D -> B = 25.7 ohms

Conclusive evidence that the solenoid is bad?

If so, I can't seem to find a solenoid only replacement. Everything I have seen is the whole EGR valve and solenoid together. Is this the only way to replace it?

Thank you so much for all of the help and the detailed guide!
 

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Discussion Starter #16
Well, I'm back from my vacation. I'm planning on going through the electrical checks today from the PDF you sent. If everything passes then I need to do vacuum checks?

I understand vacuum much more than I understand electricity, but I still don't know which lines and how to check them.

I'm assuming I'll be disconnecting lines with the engine running and checking for vacuum and/or a change in engine RPM?

Thanks again, and I hope everyone had a Merry Christmas!
 

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Discussion Starter #17 (Edited)
Today's update:

I just finished testing the EGR Boost Sensor Solenoid Valve and I was able to get it to function properly when applying direct battery power to it. However, I was unable to get it to function with it installed and a warm engine revved to 4k RPM. I'm not sure if that is the correct way to test it. I was trying to get the EGR Valve to open, I'm not sure how/when it opens, I'm assuming when the engine is warm and under load.

I have vacuum in the line from the EGR valve to the EGR BSSV, but no vacuum between the BSSV and the Boost Sensor.

According to this diagram it is always in the de-energized mode:







So now I have replaced the EGR Boost Sensor, tested the EGR Boost Sensor Solenoid, and tested the EGR Boost Sensor Solenoid Valve. The EGR Valve was also cleaned and seemed to open and close easily, however I have not officially confirmed it opening and closing with it installed and the engine running.

Tomorrow I will test the wiring harness and connectors according to the PDF.

Running out of options...:(
 

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Do you have a code reader of some kind and can it read anything with the EGR stuff on it? You are correct, its basical active at cruise and light throttle/loads. Not at idle and must be in gear so its not going to be seen in the driveway.

If not, another option is to test the vacuum sensor with a basic syringe and ohm meter. It should change state. Its range of operation is in the pic below. It has two leads and may be a go/no-go (on or off) and it may actually be a pressure sensor. Its range of operation is very LIMITED! Frankly a human can suck enough to trigger it I suspect. So be nice to to it. Connect ohm meter to the two leads and suck on it. Does it change state?

EGR Boost Sensor-AJ.jpg

EGR Boost Sensor-AJ.1.jpg

EGR Boost Sensor-AJ.2.jpg

Hopefully these help.
 

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Discussion Starter #19
I didn't get a chance to check the wiring harness and connectors today, but I did test the sensor by sucking on the hose that goes into the sensor, and I wasn't sure how to measure it with the ohm meter (not sure what two leads you were talking about). I did notice a change in engine RPM while I was applying suction, and another change when I stopped.

Was that the EGR valve operating that changed the RPM?

Does that mean the EGR valve and the EGR sensor seem to be working properly?
 

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Was thinking - unplug it from the car. The sensor has two leads, connect those meter leads to the sensor and set it too Ohms. Likely 0 - 500 or so and apply vacuum. Its looking for pressure drop to tell the ECM the EGR valves commanded action actually took place.

So does it still have both codes and how far have you driven it? What are you using for a code reader and what does said reader display for "Readiness"

The only thing I have up and running is a phone app Torque Pro.
 
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