Magnaflow Cat. FAILED EMMISSIONS ,
I NEED ADVICE ! Egr code P0402 !!!
Ok, this is where this POS stands.. (just frustrated, I'll take that back as soon as I pass emmisions..lol..). Ok, I ran the car for 226 miles before the "PCM" reset, that's according to the monitor that the state put in the OBDII.....then the CEL came BACK ON , I took it to my "cousins" place again to "check the codes, not clear them"... He checked the codes on the PCM, and it said that the egr valve is either bad, or plugged. Well, this is the EGR valve from my OTHER monte Carlo. (I put my "bad" egr. Alive into my good Monte Carlo and the CEL is not comming on, this is after 150-250 miles of m wife's driving, I have her good EGR in my car now). .... Now that I said that, my "Cousin" was checking the codes, and these are the codes that came up.... P0402 (EGR VALVE BAD) , then the P0420 (bad cat code).... At this time I'm pissed ! So , my cousin either ACCEDENTLY or wasn't thinking, RESET the PCM ! AAAARRRGGGGGHHHHHHhhhhhhh. ,!!!!?.. So, off I go DRIVING AGAIN to get the PCM history reset.... Then I drove another 175 miles (stopping about every 50-60 miles to turn off the car, let it set for about 10 minutes and restart... Well, NOW I'm "ready again", the monitor bells n whisles said it was ready AGAIN.. then.. 5 miles after the monitor was ready.. The damn CEL came BACK ON.. AAAAARRRGGGHHHhhhhh... I just parked it for the night... So, today took it up to AutoZone to see what codes I'm setting off now.. Well to my utter supprise, it's just the EGRvalve code... P0402.... That's exactly where I'm at now.. However, keep in mind, this is a new egr to this car, it runs fine in my other Monte and doesn't code out in that car. My question now is, what else can cause the EGR code to "fail".. What else can I clean, replace, ?????? I am at a loss.. I was gonna replace my Magna Flow high Flow Cat, but it isn't showing a cat code now (I installed the spark plug anti fouler set, seems to be working for now). There has to be something else in the system "Daisy chain" that is making it "code out". Please help me figure what can be sending a signal to the egr, or what may be causing the EGR keep that code (P0402)...... Any help would be fantastic.. Hope a lot of ASE Mech see this and. An advise me of my next step.. I Sincerly thank all of you in the Wonderful Monte Carlo Forum. Thanks.. Michael J Clemmer.......e
Monte Of The Month -- August 2014
Joined: Sep 2008
Posts: 25,145
From: Southeast PA
Here's some book information about that code:
Basically, the problem is not the valve, which explains why when you replaced it, nothing changed. When the car sets all the sensors to the ready state, the EGR flow is not what the car wants. This could be anything. o2 sensor, MAP sensor, a clog in one of the tubes, etc.
The code P0402 is often not a problem with the EGR valve itself. Rather, the EGR system is allowing excessive exhaust gases to flow back in to the combustion process or allowing them to flow when they should not, like when the vehicle is idling. Once the code P0402 has been retrieved with a scan tool, the freeze frame data should be documented and analyzed in order to determine what engine conditions were present when the code was triggered. It is recommended that the vehicle be driven in such a way as to duplicate the code setting conditions with a data streaming scan tool connected, so the behavior of the EGR actuating components and feedback sensors can be monitored. Pay close attention to the DPFE and/or EVP signal in the data stream.
Notes
Some EGR systems use two vacuum solenoids to supply and bleed vacuum to the valve. If either of these solenoids malfunction, then the valve will be open at times when it should not be, thus causing a P0402 code. Some vehicles use this type of dual vacuum solenoid EGR control.
Some EGR valves can get a piece of carbon stuck in between the pintle-shaped tip of the valve and its seat, thus causing EGR flow during improper driving conditions. This condition may not set an EGR code, but it may set misfire codes or rich running codes. One way to test for this condition is to test drive the vehicle with a data streaming scanner and study the EGR Position Sensor readings. The readings should go to 0 percent at idle. If not, there may be an obstruction in the valve, but the reading isn't off enough to set a P0402 code. This mostly happens on GM, Honda, and Acura vehicles, but it can happen on any of the Digital EGR-equipped vehicles.
Some EGR systems use two vacuum solenoids to supply and bleed vacuum to the valve. If either of these solenoids malfunction, then the valve will be open at times when it should not be, thus causing a P0402 code. Some vehicles use this type of dual vacuum solenoid EGR control.
Some EGR valves can get a piece of carbon stuck in between the pintle-shaped tip of the valve and its seat, thus causing EGR flow during improper driving conditions. This condition may not set an EGR code, but it may set misfire codes or rich running codes. One way to test for this condition is to test drive the vehicle with a data streaming scanner and study the EGR Position Sensor readings. The readings should go to 0 percent at idle. If not, there may be an obstruction in the valve, but the reading isn't off enough to set a P0402 code. This mostly happens on GM, Honda, and Acura vehicles, but it can happen on any of the Digital EGR-equipped vehicles.
Joined: Apr 2010
Posts: 12,601
From: Mentor, Ohio
Oddly, I cannot find the code in the shop book app I got, yet it sounds CRAZY familiar to me. Looking at what Chibi found, i swear I read the SAME info for a '97 Grand Prix with a 3800.
Check for vacuum leaks! Mist starting fluid around all vac lines and connections (not many line thank god). On my buddy's car, a few vac lines were BADLY dry rotted. The misting did not fruit anything but I changed the rubber pieces based on how BAD they looked!! I think I was able to replace them with pieces of hose and no more code. They were on the front of the engine.
Hope that helps some.
Check for vacuum leaks! Mist starting fluid around all vac lines and connections (not many line thank god). On my buddy's car, a few vac lines were BADLY dry rotted. The misting did not fruit anything but I changed the rubber pieces based on how BAD they looked!! I think I was able to replace them with pieces of hose and no more code. They were on the front of the engine.
Hope that helps some.
Monte Of The Month -- August 2012
Joined: Apr 2011
Posts: 6,074
From: Seattle
Also, don't forget to check the electrical portion of the EGR system. Make sure the connectors at the EGR valve and the position sensor are clean/tight and that they are receiving the correct voltage. With the negative probe of a DMM grounded and the positive probe touching the #1 terminal of the EGR harness you should see battery voltage (12.xv) with the key in the ON position. With the negative probe touching #2 terminal and the positive probe touching #4 terminal of the position sensor connector you should see 5v with the key in the ON position. If either of these circuits don't show correct voltage you need to inspect the wiring from the connectors to the PCM for damage.
If you remove the EGR to check for blockage remember to also check the adapter and piping (#3 & #4 in pic below) as well as the manifold passage. They often get overlooked.
If everything checks out okay then (as mentioned in Mike's post) a scanner will be required to test the EGR valve to determine what conditions were present when the code was triggered.
If you remove the EGR to check for blockage remember to also check the adapter and piping (#3 & #4 in pic below) as well as the manifold passage. They often get overlooked.
If everything checks out okay then (as mentioned in Mike's post) a scanner will be required to test the EGR valve to determine what conditions were present when the code was triggered.
Last edited by 03SSLE; Jan 2, 2014 at 10:08 PM.
I took the egr back off, looks very clean, I cleaned it out again, just to make sure.. I also looked at the tubing with a flashlight and all looks very good. I sprayed it with carb cleaner ,cleaned it up real good and put back together. .. I checked all the lines that I could see, everything looks great.. Where are the Vacuum lines located that you were mentioning? Also, just to let you know, the car is running GREAT... No issues at all.. I was reading a lot on the egr system, and most of it refers to an engine that's running bad, or has running issues of some kind, ie.. Won't idle, won't stay running...etc... That's why I am baffled.. Can't believe this sh&@, I mean BS.. LOL... ALSO, TOOK IT FOR ANOTHER 25 mile drive after cleaning... Still CEL ! Aaaarrrrgggghhhhhhh !
The picture that you posted with the numbers on it with the parts accompanied to it. Do you have the parts list for each of the numbers? Thanks.. Mjclemm...n
Where is the DPFE sensor located? I believe I am gonna replace that and see if it helps. Also, I want to change the bank 1 o2 senser to make sure it's not that as well. I just don't want to spend $1000s of dollars in parts replacing with out a benifit. Just doesn't make sence. I would have spent $150 on a NEW EGR Valve if I didn't have a back up Monte.. That's bs... If the code at Autozone says. BAD EGR, REPLACE.. And info and still have the same codes, I think you should be able to return the part.. Right ? I am going on THIER instruction, he said BAD EGR, period, I then said, what if its not the egr, he said. "it is, take my word for it"..lol.. I went in today and told him what I did, he said the egr is still bad... What is this ?..lol.. Wow.. I'm lost... Mjclemm
Where is the DPFE sensor located? I believe I am gonna replace that and see if it helps. Also, I want to change the bank 1 o2 senser to make sure it's not that as well. I just don't want to spend $1000s of dollars in parts replacing with out a benifit. Just doesn't make sence. I would have spent $150 on a NEW EGR Valve if I didn't have a back up Monte.. That's bs... If the code at Autozone says. BAD EGR, REPLACE.. And info and still have the same codes, I think you should be able to return the part.. Right ? I am going on THIER instruction, he said BAD EGR, period, I then said, what if its not the egr, he said. "it is, take my word for it"..lol.. I went in today and told him what I did, he said the egr is still bad... What is this ?..lol.. Wow.. I'm lost... Mjclemm
The EGR code is exactly as follows. P0402. A) possible bad egr, B) to much gas in the EGR C) excessive pressure in the EGR Valve. I am at a loss.. Thanks.. Mjclemm...
Just wondering, has everyone washed there hands on this ? Lol.. No biggie I suppose..lol.. I'm gonna end up CUBING the son a bitch soon.. Then use it as a coffee table !!!
