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99 Outback emissions monitors won't stay set


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41 replies to this topic

#1 himile99

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Posted 19 June 2013 - 01:59 AM

It's almost inspection time, and this year the wagon threw me a new curve! Every time I turn the engine off, 3 readiness monitors go to "not ready". Ever since I've owned it, the catalyst monitor has done this. Now the O2 and HO2 monitors are doing it too. It throws no codes and all applicable monitors are "ready" after my 25 mile commute, with the engine still running. Then I turn key off and back on without restarting, and bam, 3 "not readys". I'm only allowed 2 to be "not ready", anyone know what's going on here?  :/



#2 Legacy777

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Posted 19 June 2013 - 11:49 AM

Welcome to the USMB.

 

I haven't run across you issue before, but have you tried clearing the ECU's memory by disconnecting the battery for an hour or so?



#3 himile99

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Posted 19 June 2013 - 11:50 PM

I'll give it a shot tomorrow, I don't need to drive it for a couple of days. Fingers crossed...



#4 Cougar

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Posted 20 June 2013 - 06:40 AM

I suspect there could be a problem with the memory power lead to the ECU but since you say the monitors clear as soon as you shut off ignition power it might possbly mean there is a real problem with the ECU memory and you may have to replace the ECU. Check the fuses in the panel under the hood and make sure power is gets through both sides of each fuse.



#5 Fairtax4me

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Posted 20 June 2013 - 04:07 PM

O2 and Ho2 are just the oxygen sensor.
The O2 sensor will show "not ready" until it is warmed to operating temp.
After driving if you start the engine how long does it take for the monitor to reset? It should only take a few seconds if the engine and exhaust pipes are warm.

#6 himile99

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Posted 21 June 2013 - 01:27 AM

Thing is...O2 and HO2 always stayed set before, and if it was a memory failure with the ECU, why would some of them stay set?  :/



#7 nickb21

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Posted 21 June 2013 - 02:05 AM

Sounded sorta familiar.. but guess this doesn't apply to '99.. unless the ECU was swapped or something?

 

http://www.obdcleari...6_OBD_check.pdf


Edited by nickb21, 21 June 2013 - 02:07 AM.


#8 himile99

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Posted 21 June 2013 - 09:11 AM

I've had the car for 6 years and never touched the ECU. I believe the emissions inspection is done with the key on, engine off, right?



#9 himile99

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Posted 22 June 2013 - 12:38 AM

From a cold start the HO2 went ready before the scanner booted, O2 was not ready, but went ready in under 8 miles. Catalyst was still not ready at that point. Didn't check it after that because I was pressed for time. 



#10 johnceggleston

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Posted 22 June 2013 - 07:47 AM

how old are the sensors?

 

catalyst not ready means a sensor is measuring the cat performance.

if that is done by an an old and worn o2 senor that may be your answer.

if that sensor is also one that is not ''ready at start up, well .......

 

o2 sensors fail to work properly long before they throw a code.

 

just a thought.


Edited by johnceggleston, 22 June 2013 - 07:48 AM.


#11 himile99

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Posted 22 June 2013 - 10:25 AM

Hmmm...good thought!   :)  I did do the O2 sensors shortly after I got it, They've got just over a 100,000 miles on them. Might also have a very slight exhaust leak somewhere up there. Maybe this all ties in....



#12 grossgary

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Posted 22 June 2013 - 10:50 AM

ever had water in the passengers side floorboard?  that's where the ECU and wiring are.  and sometimes drains for the HVAC can leak into the cabin there, though i've never seen/heard of those that leak having ECU issues.

 

if an O2 sensor was failing i would think it would set a check engine light?  i've seen compromised O2 (and other) sensors *not* set a check engine light. the way it's failing isn't within the confines of what the ECU is looking at/for, so it doesn't see anything at all out of the ordinary.  if it's out of range for some reason that's causing the ECU glitches, like in your case, seems like it should trigger a check engine light.

 

that being said - you've obviously got a rare, non-traditional failure or symptom going on here.  the sad part is that we are positive on one thing -that it's something very simple.  tracking that something simple down may prove difficult.

 

ECU's are worthless since they almost never fail and they're super easy to swap out, i think i'd swap in another 97-99 EJ25D ECU.  someone on here no doubt has one. only one i have is 96 EJ25D and it will work just fine on yours but 96's already have readiness monitor issues and are exempt from emissions in that regard, but that wouldn't jive with emissions for a 99 vehicle.



#13 ivans imports

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Posted 22 June 2013 - 10:54 AM

They check your car every year crazy glad i live here no emition testing of any kind. I whould start by making shure no exhaust leaks of any kind reset ecu and drive it see what codes come back. Have been having lots of bad 02 s latly also check flow of egr if equiped



#14 himile99

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Posted 23 June 2013 - 01:22 AM

Here's a quick update. Swapped out the front O2 sensor for one with a lot less miles this afternoon. Fired it up and HO2 set quickly as normal. Got called in to work and managed to get there without setting the O2 monitor, but the catalyst had set!   :huh: I figure I didn't open the throttle enough. The exhaust is solid before the front cat, might be a small leak before the second cat, but I didn't have a helper today. Since both O2 sensors are in the front cat, it shouldn't affect anything. Everything set on the way home, until I turned the key off... same 3 monitors not ready...grrr!



#15 Cougar

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Posted 23 June 2013 - 04:04 AM

Well if other things are staying in the memory except those three monitors I believe you have some faulty memory positions and are going to have to replace the ECU. There really is nothing else that can cause that kind of issue.



#16 himile99

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Posted 23 June 2013 - 10:46 AM

Cougar, that is soooo not the answer I  wanted to hear...   :(



#17 grossgary

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Posted 23 June 2013 - 12:47 PM

Cougar, that is soooo not the answer I  wanted to hear...   :(

a $25 15 minute fix is not what you wanted to hear? i'd be hoping it's the ECU and not some wonky wiring, prior shady work, water infiltration related degrading wiring that crops up later too....ECU's are cheap and easy.

 

this is an easy fix. post in the parts wanted forum.  i even have one, but someone else will have more time.

 

crawlerdan is parting out a 99 OBW:  http://www.ultimates...ing-out-99-obw/

 

this yard in PA has them for $35 each, 1-814-635-3203



#18 Fairtax4me

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Posted 23 June 2013 - 12:53 PM

I have a working ECU for a 2.5 but its from a 97 so it wouldn't do you any good. However, ECUs are usually only like $35 at a u pull it yard, and since they practically never to bad people leave them in the cars so they're very easy to find. IIRC any 98 or 99 Legacy ECU should work in that car. Obviously you have a higher chance of success with an ECU from a 99 Outback, which should not be too difficult to find.

#19 grossgary

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Posted 23 June 2013 - 03:23 PM

I have a working ECU for a 2.5 but its from a 97 so it wouldn't do you any good. .

a 97 EJ25 ECU is the same isn't it?  i know it'll plug in and run the car just fine with no check engine light...not sure about the readiness monitors though?


Edited by grossgary, 23 June 2013 - 03:24 PM.


#20 Fairtax4me

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Posted 23 June 2013 - 04:17 PM

Pinouts changed in 98 IIRC from looking up info for my own ECU replacement several months ago. 95, 96-97, and 98-99 all have different pinouts, thus the ECU may not work correctly. Oddly, the plug was still the same, but the pinout was different.

#21 grossgary

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Posted 23 June 2013 - 05:04 PM

yeah odd - the engines are completely plug and play interchangeable but ECU's are not?  odd indeed. but wiring usually confuses me.



#22 himile99

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Posted 23 June 2013 - 08:59 PM

Relegated myself to finding a new ECU, so I went to grab the numbers off it. Voila, junkyard pen on it! So it's not original after all. I can't be sure it's the right one. Anyone know the correct ECU numbers for a 49 state, 2.5L, MT? Cougar, I know it's an easy fix, but finding the right one, in working condition, for under an arm and leg is going to be the hard part.



#23 Fairtax4me

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Posted 23 June 2013 - 09:49 PM

They all have some paint pen markings on them. Quality control marks or something. Both of the ones I got from the junkyard had paint pen on them while they were in the car.

There are so many different numbers and versions its almost impossible to find the exact same one, but the good news is they're mostly interchangeable. I'd just try to find an Outback. MT or AT doesn't really matter. The ECU works for either one and the wire harness in the car determines if the ECU looks for AT or MT credentials.

#24 himile99

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Posted 23 June 2013 - 10:31 PM

I actually googled the name written in paint pen. It turned up a salvage yard in Scranton, PA, the same city I bought the car in. So at least that makes sense.  :) Spent an hour looking around ebay and came up with an ECU from a 99 legacy GT, 49 state, MT, build date 7/98 (same as my OB), code AD67A. Code on my ECU is AC910. I can't see why a GT would be any different. At 110 bucks, I'm keeping it in mind. Heading for the U-Pull It in the morning. Got my fingers crossed.... 



#25 Fairtax4me

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Posted 23 June 2013 - 11:40 PM

Oooh, a name written on it is different.
So you have a repeat offender!
Have to wonder the reason for replacement of the original.




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