Code 25 Update: So I'd been doing some more reading in addition to the advice given in this thread. It just seemed to ironic that I had i was throwing a code 25 the next day after replacing my alternator and my o2 sensor(s) were shot.

So I reset the ecu a couple times over the past week to keep my CEL & TracOFF dummy lights from illuminating with full intention of find & seeking out the problem today on my day off.

So here's what I found out.
A. replacing a fuel filter is a huge pain in the A$$!
B. don't do it in your Pepsi work-issued clothing - (gas / oil / de-icer) is a tough stain to get out
C. When replacing the alternator I must have disconnected one of the vacuum hoses accidentally. (See picture)

Other Work Performed Today:
1. Replaced thermostat.
2. Replaced Coolant Reservoir (Thanks Turbodremz )
2. Drained / Replaced Engine Coolant / Antifreeze
3. Ran a Seafoam Treatment per these instructions

All n all. Pretty good days work. Drove the car about 40 miles after the Seafoam treatment. No coolant leaks, no thrown engine codes. Hopefully this is the last time I need to update this thread due to the code 25 issue.

Thanks to all that chimed in with suggestions.

 

Well..... Strike one on the Code 25 repairs..... Apparently it's not the fuel filter....
Like on the other thread I've been reading - I'm guessing it's either the o2 sensor AND / OR cat...

Sure wish there was a way to tell which it is without blindly dumping more money into it.
If there is a DIY on replacing the o2 sensors on this forum ANYWHERE I would sure love a link for it. As of right now I've saved 15% just by switching to Geico and by doing the repairs myself. If replacing an o2 sensor isn't too difficult I'm planning on taking a stab at that too..

 

Replacing the o2 sensor is very basic. All you need is an open end wrench, PB blaster, Penetrating oil, WD40, and any other lubricating oil.
This link/thread is kinda similiar to the SC. o2 sensors are o2 sensors. It will be the same on a cavalier.
https://www.clublexus.com/forums/per...placement.html

 

Slide.. so clutch .. Thanks for the link

 

let us know what happens. I really hope my code 25/26 stays off. I tightened gas cap, ran lucas fuel additive, did cap and rotor. so far so good, still have new plugs and fuel filter on my shelf in case it comes back on.

 

o2 sensors need to be changed every 100k or so at the least. when they go you just waste gas. its worth it if you are getting the codes.

If your o2 sensor looks like the screw on type without the flange, use a good o2 sensor socket to get them off or they will strip out. IF they are the 2 bolt flange type then those are easier a regular socket will do.

 

Thanks for that Tip Ali.

Finding a shop an Import shop in town is tough. However, I did talk to someone who could do diagnostics on my car and see what the issue(s) at hand is. My fear of course is replacing the upstream o2 sensors & then it not being the problem. Obviously it's good to have new sensors but with mortgage, daycare, and other monthly expenses I'm not able to just throw money at a problem that might not be the cause. After speaking to the Automotive Shop, he also suggested that. Said his rate for a full hour would be 75 dollars.

Opinions?

Should I just bite the bullet and let them do the diagnostics on the code 25. He said it could potentially be a Coolant Temperature Sensor? or anything. Not necessarily an o2 sensor. Also stated that o2 sensors are one of the most frequent misdiagnosed car problems that shadetree mechanics make.

Please chime in. Thanks.

 

I'm on Rockauto looking at o2 sensors. I'm seeing the BOSCH Part # 13470 OE Type - Exact Fit; Heated; Wires: 4; Length (in): 9.4
UPSTREAM for 51.79.

Am I needing to purchase two of these? I believe it was mentioned there are 2 Upstream o2 sensors and 2 downstream o2 sensors. BOSCH seems to be the only plug n play style replacement o2 sensors I'm not really feeling like splicing wires and all that other Jazz. A Little help here.. Thanks.

 

bump this please

 

Alright gang,

Help me out here.... I'm looking for the o2 sensor on the drivers side - pre cat converter. I've been scouring around for a picture of it, a DIY for it, anything I could find, but my venture has been fruitless. Is there anyone who can help me out here on locating it, and give me some instructions on the best way to tackle the replacement. My replacement o2 sensor arrived today. If it wasn't 5º outside right now. I'd be on this. So I may need to wait till tomorrow in hopes it warms up..

Thanks.

 

Like stated before it is very basic. Unplug battery, jack up the car, pull the emergency brake, use jack stand and lift under car. You will the 02 wrench socket, has a slit in it, or slide a 7/8 wrench around it. Spray PB Blaster or WD40 on it also if needed. Let it sit, then try to loosen. If not, spray again, then use a pry bar over the ratchet or wrench. If this doesn't get it, then apply a little heat and go from there.

I am not sure which ones, but you will need to pull the carpet back inside the car to access the plug, unless you are cutting and splicing. I am not sure which version you have bought or considering buying. You might also need to remove the supporting brackets on the exhaust to help get your wrench and socket on there properly. One on each side, then put back when done, held in by four bolts I think.

 

Sorry... I must have overlooked your DIY 1JZPWRD... I picked up the bosch

 

1JZPWRD, just wanted to say thanks for the DIY information on the o2 sensor.. Other than the grime from the oil pan it was a very easy fix. No need to pull back any interior carpet. The clip was probably the hardest thing to remove located on the outside of the car.

New timing belt, power steering pump, water pump, & belt tension pulley to be tackled tomorrow.

Here's a look at my o2 sensor at 133,300 miles.

 

Sorry to bring up a very old thread but I am also having the same problem, code 25/26. jomosc400, how did you determine which O2 sensor to replace? Or did you go ahead and replace all 4?

 

I ended up replacing both upstream o2 sensors to remedy the code 25 problem I was having.