Question, O2 upstream sensor for Trailblazer 2003 4.2L

Greetings,

I have a 2003 LS series Trailblazer 4WD with a 4.2L engine. It has
44,000 miles on it, so far it only needed one part, still under
warranty, the engine... Well, It has been a year since the engine was
replaced, going to work the other day the check engine light came on.
I took it to advance auto parts and they put it on the machine to get
the error codes out of it. It came up with error code P0172, System
Too Rich. I pulled the old one out and checked it for continituity,
it is a 4 wire unit, the heater checked OK and then I put a volt meter
across the sensor lines and heated it up a little with a propane
torch, it never read over .065 volts. I thought it might be the O2
sensor, so, I picked one up. They gave me a Bosch 15285. I took out
the old one and when I was putting in the new one I noticed that it
didn't have any slits on the side like the original. I tried it in
the opening and it fit, so, I put it in. Well, the next day the check
engine came on. I thought the the computer module may need cleared so
I disconnected the battery for half an hour or so and hooked up the
battery, Check engine light came on after 20 or so miles. I know that
it may be something else. I had the check engine come on one time
because the gas cap was loose. My question would be is the Bosch
15285 the proper sensor for the upstream sensor? Is there any cheap
error reading units out there on the market?

As always, Thanks in advance,

Markus

Goto your local autozone they will probally be nice enough to put it on a
scanner for you.

The code is telling you the pcm sees a rich mixture, not necessrily a bad
sensor, a full scan should be done to properly diagnose the problem, many
things can cause the rich mixture to the point the pcm cannot adjust with
it's maximum fuel trim programming and sets a code.

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Yes, 15285 is the correct sensor in the upstream position.

Yes.
Thing is, reading the trouble code is only 5% of the diagnostic
process, although, if all you're interested in is swapnostics,
you'll be fine.

Did you use a high impedance volt meter when you tested with the
propane torch?

Greetings,

Yes I did use a impedance volt meter, I do electronic repair and used
one of my Fluke meters. I did some more reading about o2 sensors.
Found a good article about o2 sensors at.
http://www.aa1car.com/library/o2sensor.htm
I'm stuck at home today, couldn't do any testing today.
I'll keep you posted on what I find with the latest code. In the
repair business they call it shotgun repair, of course, 5 bucks for a
fist full of capacitors is a lot cheaper than these sensors.

Take care,

Markus

If it is under 5 years old and under 50K miles it is still covered by
the emissions warranty for this so a dealer should fix it for free.
-----------------
TheSnoMan.com

Snojob, that has NOT been the case for 12 model years.

The EPA mandated warranty on O2 sensors has been 2/24 since the
implementation of OBD2.

Why do you think it is an O2 sensor problem? Too rich could be any number of
things. O2 codes would be in the 130-167 area. Just getting a code is really
of little value. You need to hook it up to a scanner and see how everything
is interacting. Pull the freeze frame data and see just what was going on
when the code was set. I would think a 172 code would be more of a leaking
or dirty injector.

Hey Ahole, you can make a coment without getting nasty. ALso I do
question that comment because they have not relaxed the 5year 50K
emission standard as you suggest and they are tlking about extending
it in the future. In order to sell a car they have to certify it to
meet emissions for this period above, not just for 24K miles.
-----------------
TheSnoMan.com

Hey Snoball, you can make a comment without being wrong most of the time.

Do you live in a fucking cave or what?
Since MY 1996, it's been minor components 2/24, major components 8/80 or 10/100.

Yeah, certify to meet emissions as I stated them, 2/24 and 8/80.
This is such old news, one has to wonder how long you've had
Alzheimer's, not to mention that it's so frickin easy to learn
about on the internet. (the following link makes the big
assumption that you can actually -read-)

http://www.epa.gov/oms/consumer/warr95fs.txt

Do you see 5/50 anywhere in there?

I sure don't.

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2 22nd August 01:33 adam f External User Posts: 1	Question, O2 upstream sensor for Trailblazer 2003 4.2L Goto your local autozone they will probally be nice enough to put it on a scanner for you.

4 22nd August 02:10 aarcuda69062 External User Posts: 1	Question, O2 upstream sensor for Trailblazer 2003 4.2L Yes, 15285 is the correct sensor in the upstream position. Yes. Thing is, reading the trouble code is only 5% of the diagnostic process, although, if all you're interested in is swapnostics, you'll be fine. Did you use a high impedance volt meter when you tested with the propane torch?

6 22nd August 02:10 snoman External User Posts: 1	Question, O2 upstream sensor for Trailblazer 2003 4.2L If it is under 5 years old and under 50K miles it is still covered by the emissions warranty for this so a dealer should fix it for free. ----------------- TheSnoMan.com

7 22nd August 02:10 aarcuda69062 External User Posts: 1	Question, O2 upstream sensor for Trailblazer 2003 4.2L Snojob, that has NOT been the case for 12 model years. The EPA mandated warranty on O2 sensors has been 2/24 since the implementation of OBD2.