I have a friend who has a 99 Maxima with 102K miles on it. The warranty is up now so she doesn't feel pressured to take it to the dealer anymore and is looking for some advice.

The Service Engine Soon light keeps coming on. The code is EGR Flow Malfunction P0400. She got a quote of $400 for the dealer to "clean" the EGR valve so she decided to buy a new one for only $120 and do it herself. All was well for a week or so and light came back on.

Took the EGR off again and ran a brush through the stiff metal tube at the bottom of the EGR and sprayed a bunch of carb cleaner in there. All was well for a couple of hours and the light came back again. After a couple of weeks it occurred to her that she should have waited for the carb cleaner to clear out before she reset the light. So she reset the light again and was light free for about 3 weeks, until last week when it came on again.

The last 2 times it came on when she was slowing down to stop. Don't know if that is significant or not.

She has checked it every time the light came on, has always been P0400 - EGR Flow Malfunction. A few days ago, however, it was EGR and Knock Sensor, an added bonus.

I found a few threads on here (listed below) but haven't gotten any definative fixes for this problem.

Any suggestions?

http://forums.maxima.org/showthread.php?t=399282
http://forums.maxima.org/showthread.php?t=357902
http://forums.maxima.org/showthread.php?t=351657
http://forums.maxima.org/showthread.php?t=368817

 

The small pipe going into the back of the upper-intake manifold is clogged, as is the port in the upper IM. I have the same problem right now - as do many others with those CEL codes.

You can pull the EGR and that tube and clean that tube and port out manually. I think I'm just going to replace that tube and clean out the intake port. Taking off the upper IM is the easiest way to make sure you have it clean.

 

Btw, my CEL tripped while I was sittling idle at a light. Got both the 0302 (EGR function) and 0304 (knock sensor) codes. My knock sensor has since reposted (I check for codes again) - even though the EGR one has not. I haven't hard time to go through the diagnosis of the solenoid and the valve itself, but my guess is the EGR passages to the IM are clogged.

 

I have this exact problem she has. Same year (99) same codes 302. 304. The 302 (EGR flow) causes the 304-(Knock Sensor) to trip.? I have read.

 

It might be a selonoid, mine also trips the 0302 sometimes when at a stop light. Car is vibrating alot more too when it throws the CEL. EGR passages are clean(the two tubes). I need to fix mine, the car turned off at a light when it threw the CEL again.

 

That was going to be my next question. My 99 SE has been doing this for about 2 months now, and I was wondering if it would ever cut off on me while at stop light n traffic.

 

Everyone is having EGR problems these days.

 

9 times out of ten its not just the port and tube on the back of the manifold, check the vacuum lines going to and from the diaphram. I'd seen quite a few of those plugged with some nasty **** causing a hi/low flow code

 

Even after having my tube cleaned and a cracked (original - with over 190K miles) knock sensor replaced, I too kept getting the 32 (EGR) code.

I took a chance and replaced the easiest of the 3 EGR valves - the solenoid valve, just over $90 from the dealer - and the code disappeared. So I'd suggest just throwing in a new EGR and canister control solenoid valve. It worked for me, and only took about 20 minutes to replace.

 

oh look, a 4 year old thread!

 

Holy hell, I completely forgot about this thread. Mainly because it's from 2005

 

IBTL!!