'99 SW2 next problem...P0133
 

Got the Check Engine Soon light on the dash driving the car in to work this morning, borrowed a reader and it gives me P0133 (Oxygen Sensor circuit slow)...how many O2 sensors am I looking at on the dohc 1.9?

edit: ah, search helped me out this time! looks like 2 sensors, one in the ex manifold and one further downstream to monitor cat...wonder which one the P0133 might be referring to??

edit2: So, I guess the P0133 indicates slow response from sensor 1...should I be leaping to the conclusion that it is the ex manifold sensor that is designated sensor 1? And, does slow response indicate replacement is necessary, or just cleaning or wiring problems?

this code is for the front 02 sensor in the exhaust manifold. It gets contaminated over time and its response time to the exhaust gas contents slows down and pisses off the pcm, which then starts adding extra gas and screws up the air/fuel mix, causing your mileage to suffer.

I personally recommend you use a denso brand replacement -- don't remember who carries them but it is essentially the aftermarket version of the Saturn Denso OEM part without the markup.

DENSO Part # 2341022 at rock auto. Double check me.
Autozone carries this identical sensor for twice the price special order.
You can shop around.
I found my sattys run like poopy on bosch O2's. Others may have different results.

You'll need an O2 socket which you can find at autozone etc. Not too expensive.

Slightly warm the car up before attempting to remove existing one. remember it has been seeing nasty hot exhaust gases and elevated temperatures for years and rust will be involved.

I think the new one will come with anti-seize compound already on the threads. If not, apply some or you will never get it out come replacement time.

Enjoy

On my way to O'Reilly's to see what they've got...

Thanks a mil, Derf!

Advance Auto shows to have the Denso O-2 sensor part# 234-1022 for $47.99 at my local store.

twice the price of rock auto

I found one here in Livermore for $49.00....only one in the nearby vicinity, as far as i can tell...

Goes to show what a profit margin they really have, doesn't it?

FYI, I used a generic Bosch one wire sensor that cost me around $15, crimped the old connector to the new wire and haven't had any issues with it.