99 i30: Error Codes P0325 and P0400

The club for Nissan Maxima and Infiniti I30 / I35 owners, and the official home of Maxima Club of America!
99_i30
Posts: 2
Joined: Thu Jul 31, 2008 3:56 pm
Car: '99 I30

Post

Went to Autozone for the free diagnostics and these were the 2 codes that came up:

P0400: EGR Flow MalfunctionP0325: Knock Sensor 1 Ckt Malfunction Bnk 1 or Single Sensor

I'm not handy enough to attempt to fix these myself so will most likely take it to a mechanic. But I wanted to know how serious these problems are and how immediate of attention it warrants. Also, any estimate or general price range for how much it should cost to fix would be greatly appreciated.

I was planning on taking a little road trip next week (250 miles there and another 250 back) but would you advise that I hold off on it till I take it to a mechanic to fix? Or is it safe to keep driving even with these codes? Any similar experience you can share would be great! Thank you!!


tmars04
Posts: 1
Joined: Fri Oct 03, 2008 6:14 am
Car: 1999 Maxima, 2004 Infinity I35 (two of them)

Post

The Knock Sensor will not light the Check Engine Indicator. The EGR Flow Malfunction error is probably not the EGR Valve itself. From all that I read, they rarely go bad. I called the dealer, and he confirmed the above. Most likely a clogged hose from/to the EGR, or a temp sensor. I been driving my 1999 Maxima for a year with those codes, as the cost to repair seemed high for my Maxima with 136,000 miles on it. I periodically re-set the ECM. The Knock sensor error displays immediately, but the EGR flow indicator requires some driving to confirm the error. I'm going to clean the hoses to/from the EGR first this weekend. Other input is welcome. See other posts on this topic as well.

99_i30
Posts: 2
Joined: Thu Jul 31, 2008 3:56 pm
Car: '99 I30

Post

I had a mechanic clean the tubes/hoses and reset the ECU. It was fine for a while but the light came back on after about 300 miles. Then took it back to a mechanic and replaced the solenoid, reset the ECU. Light came back on after 275 miles. I think the next step the mechanic is saying is to take apart the manifold and replace the EGR, which can be very costly.

Any other options? Curious how it took about 275 miles each time for the light to come back on... Should I just reset my ECU after every 275 miles?

User avatar
allensteiner
Posts: 1193
Joined: Mon Oct 22, 2007 2:55 pm
Car: 1995 Nissan Maxima GLE, 2005 Pontiac Bonneville SE

Post

don't worry about the egr since it doesn't do much anyways and quite a few guys just get rid of it altogether. the knock sensor code might be caused by a bad o2 sensor (don't ask me how) so since the car has a few years and miles on it replace those if anything for better mpg.

i pulled my check engine light bulb a while ago...because i know better what's wrong than the ecu

jdjohn
Posts: 10
Joined: Sun Oct 18, 2009 4:29 pm

Post

Fine w/ me, but the emissions people seem to have a problem with it

jdjohn
Posts: 10
Joined: Sun Oct 18, 2009 4:29 pm

Post

A real answer would be nice, though. I've got the same two codes plus one of the O2 sensors (P0136). I know the KS code is bogus because the car runs fine. I have already replaced one O2 sensor, but I think I changed the wrong one. I guess I'll check the EGR tubes/hoses first as suggested for that code.

Jody

User avatar
loystock
Moderator
Posts: 2144
Joined: Sun Sep 21, 2003 9:12 pm
Car: 10 Pilot, 97&03 Q45s, 97 I30 and 06 M35 Sports (04 G35 & 99 I30-RIP)
Location: San Jose, CA

Post

You have to address the O2 sensor problem as you car may be running rich which may eventually damage the catalytic converter (OEM cat is very expensive). You also have to indicate which model year you have as there as differences in the number and location of sensors. 99 and earlier Federal emission configuration has 3 O2 sensors - 2 front and 1 at the rear (after the main cat). 99 CA and 00 and beyond Federal configuration have 4 sensors - 2 front and 2 rear and all of them mounted close to the respective pre-cats (nothing installed downstream of the main cat).

NutriaforBreakfast
Posts: 1316
Joined: Wed Sep 26, 2007 1:41 pm
Car: Nissan Maxima 1995 VQDE engine

Post

Had these same codes on my 95 Maxima. I think the PO325 code(knock sensor) is a "ghost" code which throws with the EGR codePO400

Check to see if EGR valve moves when you give it gas by feeling itwith your hand. If it does NOT move and your engine is NOT stalling orrunning poorly, the valve is closed. The reason it is closed could be formany reasons;1) EGR temp sensor is out 2) EGR Solenoid is faulty3)EGR BPT valve is not getting vacuum or carboned up4) Loose hose5) Various iron tubes clogged6)EGR valve is faulty7) Carbon is stopping something up

Use the shop manual to check these items and see if any are wornout. You will need a MYTVAC vaccuum tester and a multimeter to checkvoltage and resistance.

Anyway, since my car has been reliable, I broke down and replaced allof the items and the code never came back ($325) after they were clearedand it passed inspection.

Big problem on this car to diagnose since many of items are really buried under the plenum or low or in a tight spot. It was just easier to replace all the parts rather than onepart at a time.


jdjohn
Posts: 10
Joined: Sun Oct 18, 2009 4:29 pm

Post

Looks like the intake manifold has to be taken off to get to the EGR exhaust tube, and definitely the throttle body has to be removed to get to anything EGR-related.


Return to “Maxima Forum & I30 / I35 Forum”