Question regarding the origins of DTC 0302 - EGR Valve issue
04-17-2003, 05:52 AM
#1
Question regarding the origins of DTC 0302 - EGR Valve issue
In my research, I can't tell who here has received a 0302 code on 99 model Maximas. I state this because the EGR system for 99 Maximas is entirely different from 95 to 98 Maximas. Right now I'm trying to determine how to tackle my issues.
A little history:
Early summer of 2002, I replace my spark plugs with copper NGKs.
Late summer of 2002, I get the wonderful 0201 ignition code, indicating one or more coil packs are toast. Of course, I don't get the corresponding cylinder misfire. Reverse felt like the engine was shaking off its mounts, idling would occasionally get rough, only tended to occur in extreme temp conditions (really cold, really hot) as well as high humidity conditions, all indicating one or more faulty coils. I eventually replace the cylinder 2 and cylinder 4 coil packs (the middle of each bank) in around December 2002.
0201 code has not returned since. However, a "miss" still occasionally occurs and it occasionally shakes in reverse. I haven't really noticed the weather conditions.
The past few weeks I have received the 0302 code twice, which is EGR insufficient or excessive flow.
I believe my issues are coincidental and not related
My questions:
Is cleaning the EGR system any different/more difficult than the 95 to 98 models?
Would bad coil packs then leading to overly fouled plugs cause an EGR issue?
Will replacing the other 4 coil packs going to solve my issues or will I be throwing money at something that theoretically ?
I realize these questions won't have clear cut answers, as it's possible one action/solution is dependent on another. I'm sort of in brainstorming mode at this point.
ADTHANKSVANCE
A little history:
Early summer of 2002, I replace my spark plugs with copper NGKs.
Late summer of 2002, I get the wonderful 0201 ignition code, indicating one or more coil packs are toast. Of course, I don't get the corresponding cylinder misfire. Reverse felt like the engine was shaking off its mounts, idling would occasionally get rough, only tended to occur in extreme temp conditions (really cold, really hot) as well as high humidity conditions, all indicating one or more faulty coils. I eventually replace the cylinder 2 and cylinder 4 coil packs (the middle of each bank) in around December 2002.
0201 code has not returned since. However, a "miss" still occasionally occurs and it occasionally shakes in reverse. I haven't really noticed the weather conditions.
The past few weeks I have received the 0302 code twice, which is EGR insufficient or excessive flow.
I believe my issues are coincidental and not related
My questions:
Is cleaning the EGR system any different/more difficult than the 95 to 98 models?
Would bad coil packs then leading to overly fouled plugs cause an EGR issue?
Will replacing the other 4 coil packs going to solve my issues or will I be throwing money at something that theoretically ?
I realize these questions won't have clear cut answers, as it's possible one action/solution is dependent on another. I'm sort of in brainstorming mode at this point.
ADTHANKSVANCE
04-17-2003, 06:12 AM
#2
Member who somehow became The President of The SE-L Club
iTrader: (19)
Join Date: Jun 2001
Posts: 16,033
Bill I think you have 2 isolated issues going on. The miss is probably a coil or it could be the copper plugs throwing it also. For 60 bucks I'd throw the Plats back in there. It could be a much cheaper fix then coil packs. While your in there check all the coils throughly for any cracks in the stalk where you could get an arch to the valve cover. Some have solved the miss problem by wrapping them with black tape. I find this to be gettoh (sp?) but might be worth a shot.
Now onto the EGR issue. This may sound crazy but my buddies I30 would throw EVAP and EGR codes regularly. He just lived with the check engine light.
Then we cleaned his TB one day, including making the car injest the cleaner while it was running as a last step. That was over a year ago and the car has never thrown a code since. I think he had a vacuume line that runs from around the TB area that may have been plugged with grime. He doesn't change his oil regularly and the blow by he gets is really dirty and gums up his TB pretty good.
That might be a long shot, but it may also save you a lot of time in troubleshooting as well. The whole system is vacuume operated and if a line is slightly plugged up someplace, the EGR valve may not be opening enough to allow sufficent flow, thus giving you that code. I can't believe that your 99 would have enough carbon built up to clog your EGR system by now, especially the way you maintain your car. So check the system that activates it first.
Hope that helps you out.
Now onto the EGR issue. This may sound crazy but my buddies I30 would throw EVAP and EGR codes regularly. He just lived with the check engine light.
Then we cleaned his TB one day, including making the car injest the cleaner while it was running as a last step. That was over a year ago and the car has never thrown a code since. I think he had a vacuume line that runs from around the TB area that may have been plugged with grime. He doesn't change his oil regularly and the blow by he gets is really dirty and gums up his TB pretty good.That might be a long shot, but it may also save you a lot of time in troubleshooting as well. The whole system is vacuume operated and if a line is slightly plugged up someplace, the EGR valve may not be opening enough to allow sufficent flow, thus giving you that code. I can't believe that your 99 would have enough carbon built up to clog your EGR system by now, especially the way you maintain your car. So check the system that activates it first.
Hope that helps you out.
04-17-2003, 06:12 AM
#3
Senior Member
Join Date: Feb 2003
Posts: 204
Re: Question regarding the origins of DTC 0302 - EGR Valve issue
Originally posted by bill99gxe
In my research, I can't tell who here has received a 0302 code on 99 model Maximas. I state this because the EGR system for 99 Maximas is entirely different from 95 to 98 Maximas. Right now I'm trying to determine how to tackle my issues.
A little history:
Early summer of 2002, I replace my spark plugs with copper NGKs.
Late summer of 2002, I get the wonderful 0201 ignition code, indicating one or more coil packs are toast. Of course, I don't get the corresponding cylinder misfire. Reverse felt like the engine was shaking off its mounts, idling would occasionally get rough, only tended to occur in extreme temp conditions (really cold, really hot) as well as high humidity conditions, all indicating one or more faulty coils. I eventually replace the cylinder 2 and cylinder 4 coil packs (the middle of each bank) in around December 2002.
0201 code has not returned since. However, a "miss" still occasionally occurs and it occasionally shakes in reverse. I haven't really noticed the weather conditions.
The past few weeks I have received the 0302 code twice, which is EGR insufficient or excessive flow.
I believe my issues are coincidental and not related
My questions:
Is cleaning the EGR system any different/more difficult than the 95 to 98 models?
Would bad coil packs then leading to overly fouled plugs cause an EGR issue?
Will replacing the other 4 coil packs going to solve my issues or will I be throwing money at something that theoretically ?
I realize these questions won't have clear cut answers, as it's possible one action/solution is dependent on another. I'm sort of in brainstorming mode at this point.
ADTHANKSVANCE
In my research, I can't tell who here has received a 0302 code on 99 model Maximas. I state this because the EGR system for 99 Maximas is entirely different from 95 to 98 Maximas. Right now I'm trying to determine how to tackle my issues.
A little history:
Early summer of 2002, I replace my spark plugs with copper NGKs.
Late summer of 2002, I get the wonderful 0201 ignition code, indicating one or more coil packs are toast. Of course, I don't get the corresponding cylinder misfire. Reverse felt like the engine was shaking off its mounts, idling would occasionally get rough, only tended to occur in extreme temp conditions (really cold, really hot) as well as high humidity conditions, all indicating one or more faulty coils. I eventually replace the cylinder 2 and cylinder 4 coil packs (the middle of each bank) in around December 2002.
0201 code has not returned since. However, a "miss" still occasionally occurs and it occasionally shakes in reverse. I haven't really noticed the weather conditions.
The past few weeks I have received the 0302 code twice, which is EGR insufficient or excessive flow.
I believe my issues are coincidental and not related
My questions:
Is cleaning the EGR system any different/more difficult than the 95 to 98 models?
Would bad coil packs then leading to overly fouled plugs cause an EGR issue?
Will replacing the other 4 coil packs going to solve my issues or will I be throwing money at something that theoretically ?
I realize these questions won't have clear cut answers, as it's possible one action/solution is dependent on another. I'm sort of in brainstorming mode at this point.
ADTHANKSVANCE
04-17-2003, 06:24 AM
#4
Re: Re: Question regarding the origins of DTC 0302 - EGR Valve issue
Originally posted by supercobraz
Say, when you got those codes about the EGR, did you get a check engine light first or did you just check for codes? Reason I ask is I think I have problems with my EGR system on my 98, but not sure
Say, when you got those codes about the EGR, did you get a check engine light first or did you just check for codes? Reason I ask is I think I have problems with my EGR system on my 98, but not sure
04-17-2003, 06:26 AM
#5
Senior Member
Join Date: Feb 2003
Posts: 204
Re: Re: Re: Question regarding the origins of DTC 0302 - EGR Valve issue
Originally posted by bill99gxe
The check engine light appeared first, then I checked the codes. Only the 0302 one has surfaced with regards to the EGR system.
The check engine light appeared first, then I checked the codes. Only the 0302 one has surfaced with regards to the EGR system.
04-17-2003, 06:33 AM
#6
Originally posted by njmaxseltd
Bill I think you have 2 isolated issues going on. The miss is probably a coil or it could be the copper plugs throwing it also. For 60 bucks I'd throw the Plats back in there. It could be a much cheaper fix then coil packs.
Bill I think you have 2 isolated issues going on. The miss is probably a coil or it could be the copper plugs throwing it also. For 60 bucks I'd throw the Plats back in there. It could be a much cheaper fix then coil packs.
I didn't notice a change for several months with the coppers in there. I think/hope that's a red herring.
However, I do think the coppers would foul quicker if one or more coil packs are bad/continue to be bad.
While your in there check all the coils throughly for any cracks in the stalk where you could get an arch to the valve cover. Some have solved the miss problem by wrapping them with black tape. I find this to be gettoh (sp?) but might be worth a shot.
Hmmmm...interesting suggestion. I'll look into that. I have yet to get a coil pack to bench test "bad"; replacing 1 didn't stop the CELs from coming, but replacing 2 of them did. Of course, that doesn't mean it's "fixed" either.
Now onto the EGR issue. This may sound crazy but my buddies I30 would throw EVAP and EGR codes regularly. He just lived with the check engine light. Then we cleaned his TB one day, including making the car injest the cleaner while it was running as a last step. That was over a year ago and the car has never thrown a code since. I think he had a vacuume line that runs from around the TB area that may have been plugged with grime. He doesn't change his oil regularly and the blow by he gets is really dirty and gums up his TB pretty good.
Then we cleaned his TB one day, including making the car injest the cleaner while it was running as a last step. That was over a year ago and the car has never thrown a code since. I think he had a vacuume line that runs from around the TB area that may have been plugged with grime. He doesn't change his oil regularly and the blow by he gets is really dirty and gums up his TB pretty good.
Two things here:
I have yet to clean the TB, so I am intending on doing that. I'll also check the vacuum lines while I'm at it.
Blow-by is possible with me since my viscosity is in a high 40-weight oil range with the Amsoil 1 year oil replacement approach. I'm thinking this could contribute to EGR "plugging" up as well. Needless to say, my oil intervals will be changing (looking at 8 month intervals now after doing a couple of 3 to 4 month intervals to normalize the viscosity).
One other thing:
Would replacing the PCV valve be wise at this point (56k)?
04-17-2003, 06:42 AM
#7
Senior Member
Join Date: Feb 2003
Posts: 204
Originally posted by bill99gxe
I didn't notice a change for several months with the coppers in there. I think/hope that's a red herring.
However, I do think the coppers would foul quicker if one or more coil packs are bad/continue to be bad.
[/B]
Hmmmm...interesting suggestion. I'll look into that. I have yet to get a coil pack to bench test "bad"; replacing 1 didn't stop the CELs from coming, but replacing 2 of them did. Of course, that doesn't mean it's "fixed" either.
[/B]
Two things here:
I have yet to clean the TB, so I am intending on doing that. I'll also check the vacuum lines while I'm at it.
Blow-by is possible with me since my viscosity is in a high 40-weight oil range with the Amsoil 1 year oil replacement approach. I'm thinking this could contribute to EGR "plugging" up as well. Needless to say, my oil intervals will be changing (looking at 8 month intervals now after doing a couple of 3 to 4 month intervals to normalize the viscosity).
One other thing:
Would replacing the PCV valve be wise at this point (56k)? [/B]
I didn't notice a change for several months with the coppers in there. I think/hope that's a red herring.
However, I do think the coppers would foul quicker if one or more coil packs are bad/continue to be bad.
[/B]
Hmmmm...interesting suggestion. I'll look into that. I have yet to get a coil pack to bench test "bad"; replacing 1 didn't stop the CELs from coming, but replacing 2 of them did. Of course, that doesn't mean it's "fixed" either.
[/B]
Two things here:
I have yet to clean the TB, so I am intending on doing that. I'll also check the vacuum lines while I'm at it.
Blow-by is possible with me since my viscosity is in a high 40-weight oil range with the Amsoil 1 year oil replacement approach. I'm thinking this could contribute to EGR "plugging" up as well. Needless to say, my oil intervals will be changing (looking at 8 month intervals now after doing a couple of 3 to 4 month intervals to normalize the viscosity).
One other thing:
Would replacing the PCV valve be wise at this point (56k)? [/B]
04-17-2003, 07:16 AM
#8
Member who somehow became The President of The SE-L Club
iTrader: (19)
Join Date: Jun 2001
Posts: 16,033
Originally posted by bill99gxe
One other thing:
Would replacing the PCV valve be wise at this point (56k)?
One other thing:
Would replacing the PCV valve be wise at this point (56k)?
Good luck Bill, do try the TB cleaning and PCV valve first. Let us know how you make out.
Tom
04-17-2003, 07:22 AM
#10
Originally posted by njmaxseltd
It is part of the EGR/EVAP system and it's only a few bucks.
Good luck Bill, do try the TB cleaning and PCV valve first. Let us know how you make out.
Tom
It is part of the EGR/EVAP system and it's only a few bucks.
Good luck Bill, do try the TB cleaning and PCV valve first. Let us know how you make out.
Tom
supercobraz,
I'm thinking the PCV changing could help due to possible blowby and my (lack of) oil change history....
04-17-2003, 07:32 AM
#11
Senior Member
Join Date: Feb 2003
Posts: 204
Originally posted by bill99gxe
Thanks, will do.
supercobraz,
I'm thinking the PCV changing could help due to possible blowby and my (lack of) oil change history....
Thanks, will do.
supercobraz,
I'm thinking the PCV changing could help due to possible blowby and my (lack of) oil change history....
05-13-2003, 11:09 AM
#12
UPDATE: Here's what I've done:
PCV Valve Changed - It was stuck from all the oil blowby; changing that thing sucks
Throttle Body Cleaning - Again, oil blowby contributed to gumming it up pretty good
Copper Plugs Replaced - Only one was out of gap or looked bad, and it was attached to one of the two coils that had gone "bad" last year
Fuel Filter - Had been on there 30k; replaced with another 300z oversized filter
IACV cleaned - Purchased a new OEM IACV gasket 23875-AD100 for a whole $1.24, took the housing off and cleaned out the IACV housing (fairly nasty) and the IACV itself (black oblong piece held on to the IACV housing with two screws). Bench tested the IACV and terminals were at 38 to 40 ohms.
Theoretically, it should be 30 ohms always.
EGR Valve bench tested - Tested exactly in-spec for the 1999 specific part according to the Chilton's manual. I believe it's 20 or 24 ohms at each terminal.
Re-set the idle adjusting the throttle plate screw. I think it's now idling around 700rpm. MUCH better overall when sitting still.
Results:
Still getting a 0302 code every 2 to 3 days.
Where to go from here:
Not sure. I can't really trace any vacuum lines in or around the EGR area, so if any are plugged I don't really know what to look for.
IACV tests "bad", but I'm not sure if the ambient temperature has a significant effect on the resistance values of the IACV. Service manual just says replace. 0302 code mentions nothing about the IACV being the issue......
EGR tests "good", but DAVEB @ South Point thinks this is the issue as the 99 EGR valves aren't known for their reliability.
I do think I am a commercial for why not to extend your oil drains for 1 year with "severe" stop and go driving conditions. The effect of higher oil viscosity obviously "gummed up" the works so to speak in the intake and exhaust components.
Any other suggestons?
PCV Valve Changed - It was stuck from all the oil blowby; changing that thing sucks
Throttle Body Cleaning - Again, oil blowby contributed to gumming it up pretty good
Copper Plugs Replaced - Only one was out of gap or looked bad, and it was attached to one of the two coils that had gone "bad" last year
Fuel Filter - Had been on there 30k; replaced with another 300z oversized filter
IACV cleaned - Purchased a new OEM IACV gasket 23875-AD100 for a whole $1.24, took the housing off and cleaned out the IACV housing (fairly nasty) and the IACV itself (black oblong piece held on to the IACV housing with two screws). Bench tested the IACV and terminals were at 38 to 40 ohms.
Theoretically, it should be 30 ohms always.EGR Valve bench tested - Tested exactly in-spec for the 1999 specific part according to the Chilton's manual. I believe it's 20 or 24 ohms at each terminal.
Re-set the idle adjusting the throttle plate screw. I think it's now idling around 700rpm. MUCH better overall when sitting still.
Results:
Still getting a 0302 code every 2 to 3 days.
Where to go from here:
Not sure. I can't really trace any vacuum lines in or around the EGR area, so if any are plugged I don't really know what to look for.
IACV tests "bad", but I'm not sure if the ambient temperature has a significant effect on the resistance values of the IACV. Service manual just says replace.
0302 code mentions nothing about the IACV being the issue......EGR tests "good", but DAVEB @ South Point thinks this is the issue as the 99 EGR valves aren't known for their reliability.
I do think I am a commercial for why not to extend your oil drains for 1 year with "severe" stop and go driving conditions. The effect of higher oil viscosity obviously "gummed up" the works so to speak in the intake and exhaust components.
Any other suggestons?
05-13-2003, 08:34 PM
#13
Supporting Maxima.org Member
Join Date: Jul 2002
Posts: 205
The egr will cause a misfire if it is leaking. What you can try is remove the valve and make a gasket to cover the passages. You will still get the 0302 code because you just disabled the egr system. This will only tell you if your valve is leaking and causing the misfire.
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