Code P0420-Catalyst Efficiency Below Threshhold Bank 1

[Carl 1 Lucky Texan]

Carl..
Thanks for your response.
The CATS are original - 165,000+ miles. Ditto the 02 sensors.
Never blown headgaskets or run the car rich (unless the computer chose
to do so).
Technician did say that one was just above the pass threshhold, which
I assume means he measured something? Not sure if that addresses any
of the suggestions in your first paragraph (not being a technician). I
can run those by him.

Jim

Well, 165K is getting elderly for a lot of components - buthat would be
a pretty extreme lifespan for the original sensors I think. many are
getting lazy at 80-120K.

It comes down to this, it would be better to be wrong about the sensors
than wrong about the converter. bya factor of 15-20! personally, I would
want to try changing the front O2 sensor (it is exposed to more heat and
somewhat more corrosive gasses than the rear one) and clear the codes
and wait to see if any return. Start saving your money, and maybe
research discount/online dealer prices for the converter (try
www.subarugenuineparts.com) and maybe the local dealership will match
the price.

basically, these two sensors are monitoring the gasses entering and
exiting the converter. If readings are outside some limit, they set the
code. There is no 'direct' converter measurement so, if an O2 sensor is
reading incorrectly - it could throw the very same code, erroneously
'blaming' the converter. Kinda like a person going blind and telling
people the lights need replacing! Of course there is a 'heater' circuit
that could also fail in the (front I think?) converter. But that doesn't
seem to tbe the case here.

hey, I'm just some guy that reads a lot on the internet and occasionally
tinkers with cars. If you feel the dealership is being up-front about
everything and has done the proper testing - then you probably should
proceed.

good luck

Carl

 

[Carl 1 Lucky Texan]

Well, 165K is getting elderly for a lot of components - buthat would be
a pretty extreme lifespan for the original sensors I think. many are
getting lazy at 80-120K.

It comes down to this, it would be better to be wrong about the sensors
than wrong about the converter. bya factor of 15-20! personally, I would
want to try changing the front O2 sensor (it is exposed to more heat and
somewhat more corrosive gasses than the rear one) and clear the codes
and wait to see if any return. Start saving your money, and maybe
research discount/online dealer prices for the converter (try
www.subarugenuineparts.com) and maybe the local dealership will match
the price.

basically, these two sensors are monitoring the gasses entering and
exiting the converter. If readings are outside some limit, they set the
code. There is no 'direct' converter measurement so, if an O2 sensor is
reading incorrectly - it could throw the very same code, erroneously
'blaming' the converter. Kinda like a person going blind and telling
people the lights need replacing! Of course there is a 'heater' circuit
that could also fail in the (front I think?) converter. But that doesn't
seem to tbe the case here.

hey, I'm just some guy that reads a lot on the internet and occasionally
tinkers with cars. If you feel the dealership is being up-front about
everything and has done the proper testing - then you probably should
proceed.

good luck

Carl

Try googling some O2 and cat con info. here's coupla sites I found
quickly;
http://www.gnttype.org/techarea/ecmsensors/O2sensors.html
http://www.autohausaz.com/html/emissions-oxygen_sensors.html


Carl

 

[Carl 1 Lucky Texan]

Try googling some O2 and cat con info. here's coupla sites I found
quickly;
http://www.gnttype.org/techarea/ecmsensors/O2sensors.html
http://www.autohausaz.com/html/emissions-oxygen_sensors.html


Carl

another good write-up;
http://www.troublecodes.net/articles/catfailure/

 

[kaplan3jiim]

Got the subject code for check engine light pulled at Auto Zone.
Car is a '97 Subaru with 165,000 miles.

Could this be the catalytic converter? Auto Zone person said it could
be 0xygen sensor. How does on ascertain what the actual problem is?
Is the O2 sensor easily accessible on the 2.2l engine?

TIA
Jim

500 miles after replacing the two cat cons, the code came back. Shop
exmaine everything and crimped a couple connections they said might
have a tiny air leak. 500 miles later code came back and now I am
being told the front 02 sensor is definitely failing. They did say
they went through fairly exhaustive checks (as detailed elswhere in
this forum) to ensure the origina problem was the cat cons.

Here's the new wrinkle: today the alternator failed (suddenly it
seemed). After replacing the alternator and 8 year old battery, the
CEL is not on, but I'm assuming it will come back on. Unless...is
there some possibility of the code having been set my a malfunction
due to erratic voltage from a failing alternator?

TIA
Jim

 

[Todd H.]

500 miles after replacing the two cat cons, the code came back. Shop
exmaine everything and crimped a couple connections they said might
have a tiny air leak. 500 miles later code came back and now I am
being told the front 02 sensor is definitely failing. They did say
they went through fairly exhaustive checks

oh that was a terrible joke.

(I loved it)

(as detailed elswhere in
this forum) to ensure the origina problem was the cat cons.

Here's the new wrinkle: today the alternator failed (suddenly it
seemed). After replacing the alternator and 8 year old battery, the
CEL is not on, but I'm assuming it will come back on. Unless...is
there some possibility of the code having been set my a malfunction
due to erratic voltage from a failing alternator?

I'm fighting with this code too, and have no insight for ya. It
seems the "mechanic" I had who supposedly replaced my cat either
didn't, or replaced it with a used cat. At any rate, there's a big
hole in my cat that explains the code, and welding it up hasn't seemed
to solve it, unfortunately.

The front o2 was replaced earlier.

Sorry I don't have any answers, but I can comiserate. Now when I
reset the code it goes away for about 80 miles, but then comes back.

 

[kaplan3jiim]

500 miles after replacing the two cat cons, the code came back. Shop
exmaine everything and crimped a couple connections they said might
have a tiny air leak. 500 miles later code came back and now I am
being told the front 02 sensor is definitely failing. They did say
they went through fairly exhaustive checks (as detailed elswhere in
this forum) to ensure the origina problem was the cat cons.

Here's the new wrinkle: today the alternator failed (suddenly it
seemed). After replacing the alternator and 8 year old battery, the
CEL is not on, but I'm assuming it will come back on. Unless...is
there some possibility of the code having been set my a malfunction
due to erratic voltage from a failing alternator?

TIA
Jim

The saga continues. NEw 02 sensors eliminated the CEL for a few
hundred miles and a second set of catalytic converters for 1200 miles
but now it is back, same code as ever. The cat cons are not Subaru
OEM, but do have an 8 yr/50,000 mile warranty and were $600 less than
Subaru ones.

Any other more offbeat ideas of what's going on here?

TIA
Jim

 

[Carl 1 Lucky Texan]

The saga continues. NEw 02 sensors eliminated the CEL for a few
hundred miles and a second set of catalytic converters for 1200 miles
but now it is back, same code as ever. The cat cons are not Subaru
OEM, but do have an 8 yr/50,000 mile warranty and were $600 less than
Subaru ones.

Any other more offbeat ideas of what's going on here?

TIA
Jim

There are diagnostic tests. A scope will indicate to a competent
technician if the sensors are switching fast enough with the proper out
put voltage. tailpipe gas sniffers should tell a tech what's up with the
converters. A coupla other ideas - bad ground or other electrical
connection. bad/intermittent ECU.


Carl

 

[weelliott]

The saga continues.  NEw 02 sensors eliminated the CEL for a few
hundred miles  and a second set of catalytic converters for 1200 miles
but now it is back, same code as ever.  The cat cons are not Subaru
OEM, but do have an 8 yr/50,000 mile warranty and were $600 less than
Subaru ones.

Any other more offbeat ideas of what's going on here?

TIA
Jim- Hide quoted text -

- Show quoted text -

I propose that perhaps your car is just messing with you. When my car
does this, I just smack it hard. It never helps though...

But seriously. I have the same code, and am hoping it is the O2
sensor. I have a 95, and the rear O2 sensor is on the rear cat. I
tried to get it out for about 45 minutes this weekend with no luck.
It's hard to get enough torque on it to bust it loose. It seems that
one of two things always happens, I have the wrench lines up correctly
so that it holds, but then the damn sensor won't rotate, or I have it
off a little and it just slips, slowly rounding the hex part of the
sensor. I tried a plumbers wrench, but couldn't get it in there. I
also tried some PB'laster, which usually loosens rusted on crap pretty
well. I also tried running the car to heat up the cat. None of this
worked. Any ideas? I've considered a torch on the cat close to the
bung for the sensor, but dont[ know how smart that is. I don't know
how much heat it can take. Any better ideas?

I could just take it to a shop, but I feel silly takign my car to a
shop to have them unscrew something, and screw another right in.

Bill

 

[kaplan3jiim]

There are diagnostic tests. A scope will indicate to a competent
technician if the sensors are switching fast enough with the proper out
put voltage. tailpipe gas sniffers should tell a tech what's up with the
converters. A coupla other ideas - bad ground or other electrical
connection. bad/intermittent ECU.


Carl

This is getting pretty frustrating. I'm sure it would be at least as
much so if I were actually a DIY person.

I know they scoped the O2 sensors both prior to replacing the front
one (just checked the service record and only the front one has been
replaced) and after replacement when the CEL came on again (and they
were responding properly), I assume they did a sniff test (this is a
state recommended emission repair facility) and I have repeatedly
since the initial cat replacement) mentioned my concern about
electrical and computer issues.

I suppose now they could tell me it's the rear O2 sensor. But I have
no plans to replace anything further until after the car fails the
state emission test in a couple months (they just read the codes, no
actual tailpipe test) because I want any further expenditures credited
toward a waiver if one is required. I'm environmentally concerned, but
not convinced there's a real emissions issue (see last sentence of
Carl's post above)

 

[kaplan3jiim]

This is getting pretty frustrating. I'm sure it would be at least as
much so if I were actually a DIY person.

I know they scoped the O2 sensors both prior to replacing the front
one (just checked the service record and only the front one has been
replaced) and after replacement when the CEL came on again (and they
were responding properly), I assume they did a sniff test (this is a
state recommended emission repair facility) and I have repeatedly
since the initial cat replacement) mentioned my concern about
electrical and computer issues.

I suppose now they could tell me it's the rear O2 sensor. But I have
no plans to replace anything further until after the car fails the
state emission test in a couple months (they just read the codes, no
actual tailpipe test) because I want any further expenditures credited
toward a waiver if one is required. I'm environmentally concerned, but
not convinced there's a real emissions issue (see last sentence of
Carl's post above)

The next step is going to be Subaru cats, but given that the shop says
they have had no problem with the supplier/mfr of the ones they used
first and still on my car, I have a sneaking feeling this will not put
an end to this continuing saga. I hope I am wrong.

 

[kaplan3jiim]

The saga continues.  NEw 02 sensors eliminated the CEL for a few
hundred miles  and a second set of catalytic converters for 1200 miles
but now it is back, same code as ever.  The cat cons are not Subaru
OEM, but do have an 8 yr/50,000 mile warranty and were $600 less than
Subaru ones.

Any other more offbeat ideas of what's going on here?

TIA
Jim- Hide quoted text -

- Show quoted text -

I propose that perhaps your car is just messing with you. When my car
does this, I just smack it hard. It never helps though...

But seriously. I have the same code, and am hoping it is the O2
sensor. I have a 95, and the rear O2 sensor is on the rear cat. I
tried to get it out for about 45 minutes this weekend with no luck.
It's hard to get enough torque on it to bust it loose. It seems that
one of two things always happens, I have the wrench lines up correctly
so that it holds, but then the damn sensor won't rotate, or I have it
off a little and it just slips, slowly rounding the hex part of the
sensor. I tried a plumbers wrench, but couldn't get it in there. I
also tried some PB'laster, which usually loosens rusted on crap pretty
well. I also tried running the car to heat up the cat. None of this
worked. Any ideas? I've considered a torch on the cat close to the
bung for the sensor, but dont[ know how smart that is. I don't know
how much heat it can take. Any better ideas?

I could just take it to a shop, but I feel silly takign my car to a
shop to have them unscrew something, and screw another right in.

Bill

Check engine light has gone out for a week or so. Burned out, or
problem solved itself, or more likely, car messing with me...

 

[Todd H.]

57:23 -0500, (e-mail address removed) wrote:

Got the subject code for check engine light pulled at Auto Zone.  
Car is a '97 Subaru with 165,000 miles.  

Could this be the catalytic converter?  Auto Zone person said it could
be 0xygen sensor.  How does on ascertain what the actual problem is?
Is the O2 sensor easily accessible on the 2.2l engine?

TIA
Jim

500 miles after replacing the two cat cons, the code came back.  Shop
exmaine everything and crimped a couple connections they said might
have a tiny air leak.  500 miles later code came back and now I am
being told the front 02 sensor is definitely failing.  They did say
they went through fairly exhaustive checks (as detailed elswhere in
this forum) to ensure the origina problem was the cat cons.

Here's the new wrinkle: today the alternator failed (suddenly it
seemed).  After replacing the alternator and 8 year old battery, the
CEL is not on, but I'm assuming it will come back on.  Unless...is
there some possibility of the code having been set my  a malfunction
due to erratic voltage from a failing alternator?

TIA
Jim

The saga continues.  NEw 02 sensors eliminated the CEL for a few
hundred miles  and a second set of catalytic converters for 1200 miles
but now it is back, same code as ever.  The cat cons are not Subaru
OEM, but do have an 8 yr/50,000 mile warranty and were $600 less than
Subaru ones.

Any other more offbeat ideas of what's going on here?

TIA
Jim- Hide quoted text -

- Show quoted text -

I propose that perhaps your car is just messing with you. When my car
does this, I just smack it hard. It never helps though...

But seriously. I have the same code, and am hoping it is the O2
sensor. I have a 95, and the rear O2 sensor is on the rear cat. I
tried to get it out for about 45 minutes this weekend with no luck.
It's hard to get enough torque on it to bust it loose. It seems that
one of two things always happens, I have the wrench lines up correctly
so that it holds, but then the damn sensor won't rotate, or I have it
off a little and it just slips, slowly rounding the hex part of the
sensor. I tried a plumbers wrench, but couldn't get it in there. I
also tried some PB'laster, which usually loosens rusted on crap pretty
well. I also tried running the car to heat up the cat. None of this
worked. Any ideas? I've considered a torch on the cat close to the
bung for the sensor, but dont[ know how smart that is. I don't know
how much heat it can take. Any better ideas?

I could just take it to a shop, but I feel silly takign my car to a
shop to have them unscrew something, and screw another right in.

Bill

Check engine light has gone out for a week or so. Burned out, or
problem solved itself, or more likely, car messing with me...

If it makes you feel any better, I haven't done anything to mine, and
it's coming and going with that code. I know I have a small hole in
that cat though, according to the mechanic. Which of course is
irritating because I'd paid a mechanice (who's since fled to Mexico)
for a new cat about a year ago.

Seems maybe that brand of gasoline makes some sort of difference, but
I can't say exactly how.

The rubber will meet the road here soon though--emissions testing
flyer came in the mail last week. LOL.

 

[kaplan3jiim]

On Feb 6, 11:24 pm, (e-mail address removed) wrote:
57:23 -0500, (e-mail address removed) wrote:

Got the subject code for check engine light pulled at Auto Zone.  
Car is a '97 Subaru with 165,000 miles.  

Could this be the catalytic converter?  Auto Zone person said it could
be 0xygen sensor.  How does on ascertain what the actual problem is?
Is the O2 sensor easily accessible on the 2.2l engine?

TIA
Jim

500 miles after replacing the two cat cons, the code came back.  Shop
exmaine everything and crimped a couple connections they said might
have a tiny air leak.  500 miles later code came back and now I am
being told the front 02 sensor is definitely failing.  They did say
they went through fairly exhaustive checks (as detailed elswhere in
this forum) to ensure the origina problem was the cat cons.

Here's the new wrinkle: today the alternator failed (suddenly it
seemed).  After replacing the alternator and 8 year old battery, the
CEL is not on, but I'm assuming it will come back on.  Unless...is
there some possibility of the code having been set my  a malfunction
due to erratic voltage from a failing alternator?

TIA
Jim

The saga continues.  NEw 02 sensors eliminated the CEL for a few
hundred miles  and a second set of catalytic converters for 1200 miles
but now it is back, same code as ever.  The cat cons are not Subaru
OEM, but do have an 8 yr/50,000 mile warranty and were $600 less than
Subaru ones.

Any other more offbeat ideas of what's going on here?

TIA
Jim- Hide quoted text -

- Show quoted text -

I propose that perhaps your car is just messing with you. When my car
does this, I just smack it hard. It never helps though...

But seriously. I have the same code, and am hoping it is the O2
sensor. I have a 95, and the rear O2 sensor is on the rear cat. I
tried to get it out for about 45 minutes this weekend with no luck.
It's hard to get enough torque on it to bust it loose. It seems that
one of two things always happens, I have the wrench lines up correctly
so that it holds, but then the damn sensor won't rotate, or I have it
off a little and it just slips, slowly rounding the hex part of the
sensor. I tried a plumbers wrench, but couldn't get it in there. I
also tried some PB'laster, which usually loosens rusted on crap pretty
well. I also tried running the car to heat up the cat. None of this
worked. Any ideas? I've considered a torch on the cat close to the
bung for the sensor, but dont[ know how smart that is. I don't know
how much heat it can take. Any better ideas?

I could just take it to a shop, but I feel silly takign my car to a
shop to have them unscrew something, and screw another right in.

Bill

Check engine light has gone out for a week or so. Burned out, or
problem solved itself, or more likely, car messing with me...

If it makes you feel any better, I haven't done anything to mine, and
it's coming and going with that code. I know I have a small hole in
that cat though, according to the mechanic. Which of course is
irritating because I'd paid a mechanice (who's since fled to Mexico)
for a new cat about a year ago.

Seems maybe that brand of gasoline makes some sort of difference, but
I can't say exactly how.

The rubber will meet the road here soon though--emissions testing
flyer came in the mail last week. LOL.

I think my emissions test invite is due any day now too. Last done in
June of 2007.

 

[kaplan3jiim]

The saga continues.  NEw 02 sensors eliminated the CEL for a few
hundred miles  and a second set of catalytic converters for 1200 miles
but now it is back, same code as ever.  The cat cons are not Subaru
OEM, but do have an 8 yr/50,000 mile warranty and were $600 less than
Subaru ones.

Any other more offbeat ideas of what's going on here?

TIA
Jim- Hide quoted text -

- Show quoted text -

I propose that perhaps your car is just messing with you. When my car
does this, I just smack it hard. It never helps though...

But seriously. I have the same code, and am hoping it is the O2
sensor. I have a 95, and the rear O2 sensor is on the rear cat. I
tried to get it out for about 45 minutes this weekend with no luck.
It's hard to get enough torque on it to bust it loose. It seems that
one of two things always happens, I have the wrench lines up correctly
so that it holds, but then the damn sensor won't rotate, or I have it
off a little and it just slips, slowly rounding the hex part of the
sensor. I tried a plumbers wrench, but couldn't get it in there. I
also tried some PB'laster, which usually loosens rusted on crap pretty
well. I also tried running the car to heat up the cat. None of this
worked. Any ideas? I've considered a torch on the cat close to the
bung for the sensor, but dont[ know how smart that is. I don't know
how much heat it can take. Any better ideas?

I could just take it to a shop, but I feel silly takign my car to a
shop to have them unscrew something, and screw another right in.

Bill

Car continues to mess with me.

CEL light was on, then off for 750 miles or so, and is now back on.
Proposal is to return the aftermarket cats and replace with Subaru
ones. But I do wonder about one thing. When the CEL came on again
after being off,, I took the car in to have the ECU scanned. While
code P0420 remains in memory, according to the shop, the car was
listed as currently passing all tests (my paraphrase of what he said).
So although the shop insists the ECU itself cannot be an issue, I
wonder if the CEL light on but "currently passing all tests" make
sense. I know it can go off by itself after coming on from the P0420
code.

Jim

 

[StephenH]

My 2 cents.

Subaru implemented a program last year to help the Subaru tech
ACCURATELY diagnose the p0420 code. It seems as tho Subaru Warranty
was replacing too many of them that were not defective.
Unfortunately, the test requires a scan tool that can graph live data
and are watching for specific reactions between the ft AF ratio sensor
(or o2 sensor in older vehicles) and the rear sensor. It requires
driving at specific speeds and letting off on the throttle to trigger
a response.

Having worked in the aftermarket world, I do not support the use of
aftermarket o2 sensors and cats. On my dad's own truck, the
aftermarket o2 sensor didn't work correctly and required a ford OEM
sensor to cure the issue. Aftermarket cats often do not fit correctly
(Mom's car caught fire right after she traded it in - I had nothing to
do with that!) or don't quite work correctly.
The data is in a pdf format on the shops laptop/scantool, and I cannot
seem to be able to transfere it to show you. I will try to transfere
some of the important parts of it soon.

 

[S]

Hi Jim, All!

Car continues to mess with me.

I fixed this issue on a late 90s Legacy by swapping out the entire
Y-pipe/CAT/O2 sensor assembly with one from a wrecked car.

Technically, I don't think the salvage yards are supposed to resell
emission control hardware, but if you ask nicely, and ask for a
"Y-pipe" or "Front exhaust pipe" rather than a "CAT and O2 sensor",
you'll probably be able to land one.

It's been awhile, but I seem to remember spending $150 for the
assembly.

Hope this helps.

ByeBye! S.

Steve Jernigan KG0MB
Laboratory Manager
Microelectronics Research
University of Colorado
(719) 262-3101

 

[kapjim]

57:23 -0500, (e-mail address removed) wrote:

Got the subject code for check engine light pulled at Auto Zone.  
Car is a '97 Subaru with 165,000 miles.  

Could this be the catalytic converter?  Auto Zone person said it could
be 0xygen sensor.  How does on ascertain what the actual problem is?
Is the O2 sensor easily accessible on the 2.2l engine?

TIA
Jim

500 miles after replacing the two cat cons, the code came back.  Shop
exmaine everything and crimped a couple connections they said might
have a tiny air leak.  500 miles later code came back and now I am
being told the front 02 sensor is definitely failing.  They did say
they went through fairly exhaustive checks (as detailed elswhere in
this forum) to ensure the origina problem was the cat cons.

Here's the new wrinkle: today the alternator failed (suddenly it
seemed).  After replacing the alternator and 8 year old battery, the
CEL is not on, but I'm assuming it will come back on.  Unless...is
there some possibility of the code having been set my  a malfunction
due to erratic voltage from a failing alternator?

TIA
Jim

The saga continues.  NEw 02 sensors eliminated the CEL for a few
hundred miles  and a second set of catalytic converters for 1200 miles
but now it is back, same code as ever.  The cat cons are not Subaru
OEM, but do have an 8 yr/50,000 mile warranty and were $600 less than
Subaru ones.

Any other more offbeat ideas of what's going on here?

TIA
Jim- Hide quoted text -

- Show quoted text -

I propose that perhaps your car is just messing with you. When my car
does this, I just smack it hard. It never helps though...

But seriously. I have the same code, and am hoping it is the O2
sensor. I have a 95, and the rear O2 sensor is on the rear cat. I
tried to get it out for about 45 minutes this weekend with no luck.
It's hard to get enough torque on it to bust it loose. It seems that
one of two things always happens, I have the wrench lines up correctly
so that it holds, but then the damn sensor won't rotate, or I have it
off a little and it just slips, slowly rounding the hex part of the
sensor. I tried a plumbers wrench, but couldn't get it in there. I
also tried some PB'laster, which usually loosens rusted on crap pretty
well. I also tried running the car to heat up the cat. None of this
worked. Any ideas? I've considered a torch on the cat close to the
bung for the sensor, but dont[ know how smart that is. I don't know
how much heat it can take. Any better ideas?

I could just take it to a shop, but I feel silly takign my car to a
shop to have them unscrew something, and screw another right in.

Bill

Car continues to mess with me.

CEL light was on, then off for 750 miles or so, and is now back on.
Proposal is to return the aftermarket cats and replace with Subaru
ones. But I do wonder about one thing. When the CEL came on again
after being off,, I took the car in to have the ECU scanned. While
code P0420 remains in memory, according to the shop, the car was
listed as currently passing all tests (my paraphrase of what he said).
So although the shop insists the ECU itself cannot be an issue, I
wonder if the CEL light on but "currently passing all tests" make
sense. I know it can go off by itself after coming on from the P0420
code.

Jim

Well, I gave in an had a Subaru branded cat put on in July and the CEL
has never reappeared. I guess the problem really was in the prior
replacements.

 

[1 Lucky Texan]

On Mon, 9 Feb 2009 04:57:37 -0800 (PST), weelliott

On Feb 6, 11:24 pm, (e-mail address removed) wrote:
57:23 -0500, (e-mail address removed) wrote:
Got the subject code for check engine light pulled at Auto Zone.  
Car is a '97 Subaru with 165,000 miles.  
Could this be the catalytic converter?  Auto Zone person said it could
be 0xygen sensor.  How does on ascertain what the actual problem is?
Is the O2 sensor easily accessible on the 2.2l engine?
TIA
Jim
500 miles after replacing the two cat cons, the code came back.  Shop
exmaine everything and crimped a couple connections they said might
have a tiny air leak.  500 miles later code came back and now I am
being told the front 02 sensor is definitely failing.  They did say
they went through fairly exhaustive checks (as detailed elswhere in
this forum) to ensure the origina problem was the cat cons.
Here's the new wrinkle: today the alternator failed (suddenly it
seemed).  After replacing the alternator and 8 year old battery, the
CEL is not on, but I'm assuming it will come back on.  Unless...is
there some possibility of the code having been set my  a malfunction
due to erratic voltage from a failing alternator?
TIA
Jim
The saga continues.  NEw 02 sensors eliminated the CEL for a few
hundred miles  and a second set of catalytic converters for 1200 miles
but now it is back, same code as ever.  The cat cons are not Subaru
OEM, but do have an 8 yr/50,000 mile warranty and were $600 less than
Subaru ones.
Any other more offbeat ideas of what's going on here?
TIA
Jim- Hide quoted text -
- Show quoted text -
I propose that perhaps your car is just messing with you. When my car
does this, I just smack it hard. It never helps though...
But seriously. I have the same code, and am hoping it is the O2
sensor. I have a 95, and the rear O2 sensor is on the rear cat. I
tried to get it out for about 45 minutes this weekend with no luck.
It's hard to get enough torque on it to bust it loose. It seems that
one of two things always happens, I have the wrench lines up correctly
so that it holds, but then the damn sensor won't rotate, or I have it
off a little and it just slips, slowly rounding the hex part of the
sensor. I tried a plumbers wrench, but couldn't get it in there. I
also tried some PB'laster, which usually loosens rusted on crap pretty
well. I also tried running the car to heat up the cat. None of this
worked. Any ideas? I've considered a torch on the cat close to the
bung for the sensor, but dont[ know how smart that is. I don't know
how much heat it can take. Any better ideas?
I could just take it to a shop, but I feel silly takign my car to a
shop to have them unscrew something, and screw another right in.
Bill

Car continues to mess with me.  

CEL light was on, then off for 750 miles or so, and is now back on.
Proposal is to return the aftermarket cats and replace with Subaru
ones.  But I do wonder about one thing.  When the CEL came on again
after being off,, I took the car in to have the ECU scanned.  While
code P0420 remains in memory, according to the shop, the car was
listed as currently passing all tests (my paraphrase of what he said).
So although the shop insists the ECU itself cannot be an issue, I
wonder if the CEL light on but "currently passing all tests" make
sense.  I know it can go off by itself after coming on from the P0420
code.

Jim

Well, I gave in an had a Subaru branded cat put on in July and the CEL
has never reappeared.  I guess the problem really was in the prior
replacements.

thanx for updating the group on this. It may help someone doing a
search for info in the future!

 

[Dave__67]

24 pm, (e-mail address removed) wrote:
57:23 -0500, (e-mail address removed) wrote:
Got the subject code for check engine light pulled at Auto Zone.  
Car is a '97 Subaru with 165,000 miles.  
Could this be the catalytic converter?  Auto Zone person said it could
be 0xygen sensor.  How does on ascertain what the actual problem is?
Is the O2 sensor easily accessible on the 2.2l engine?
TIA
Jim
500 miles after replacing the two cat cons, the code came back.  Shop
exmaine everything and crimped a couple connections they said might
have a tiny air leak.  500 miles later code came back and now I am
being told the front 02 sensor is definitely failing.  They did say
they went through fairly exhaustive checks (as detailed elswhere in
this forum) to ensure the origina problem was the cat cons.
Here's the new wrinkle: today the alternator failed (suddenly it
seemed).  After replacing the alternator and 8 year old battery,the
CEL is not on, but I'm assuming it will come back on.  Unless...is
there some possibility of the code having been set my  a malfunction
due to erratic voltage from a failing alternator?
TIA
Jim
The saga continues.  NEw 02 sensors eliminated the CEL for a few
hundred miles  and a second set of catalytic converters for 1200 miles
but now it is back, same code as ever.  The cat cons are not Subaru
OEM, but do have an 8 yr/50,000 mile warranty and were $600 less than
Subaru ones.
Any other more offbeat ideas of what's going on here?
TIA
Jim- Hide quoted text -
- Show quoted text -
I propose that perhaps your car is just messing with you. When my car
does this, I just smack it hard. It never helps though...
But seriously. I have the same code, and am hoping it is the O2
sensor. I have a 95, and the rear O2 sensor is on the rear cat. I
tried to get it out for about 45 minutes this weekend with no luck.
It's hard to get enough torque on it to bust it loose. It seems that
one of two things always happens, I have the wrench lines up correctly
so that it holds, but then the damn sensor won't rotate, or I have it
off a little and it just slips, slowly rounding the hex part of the
sensor. I tried a plumbers wrench, but couldn't get it in there. I
also tried some PB'laster, which usually loosens rusted on crap pretty
well. I also tried running the car to heat up the cat. None of this
worked. Any ideas? I've considered a torch on the cat close to the
bung for the sensor, but dont[ know how smart that is. I don't know
how much heat it can take. Any better ideas?
I could just take it to a shop, but I feel silly takign my car to a
shop to have them unscrew something, and screw another right in.
Bill
Car continues to mess with me.  
CEL light was on, then off for 750 miles or so, and is now back on.
Proposal is to return the aftermarket cats and replace with Subaru
ones.  But I do wonder about one thing.  When the CEL came on again
after being off,, I took the car in to have the ECU scanned.  While
code P0420 remains in memory, according to the shop, the car was
listed as currently passing all tests (my paraphrase of what he said).
So although the shop insists the ECU itself cannot be an issue, I
wonder if the CEL light on but "currently passing all tests" make
sense.  I know it can go off by itself after coming on from the P0420
code.
Jim

Well, I gave in an had a Subaru branded cat put on in July and the CEL
has never reappeared.  I guess the problem really was in the prior
replacements.

thanx for updating the group on this. It may help someone doing a
search for info in the future!

There's always the anti-fouler trick...


Dave

 

[Dave]

On Jan 5, 6:43 pm, (e-mail address removed) wrote:
snip



thanx for updating the group on this. It may help someone doing a
search for info in the future!

There's always the anti-fouler trick...


Dave


Hey Dave,

What is the anti-fouler trick?

Thanks,

Dave K