O2 Sensor Replacement Help?

Hey everyone.

So I drive an 03 1.8L VW Jetta. It’s not a TDI but this is the best place I’ve found to get advice when I find myself in a jam.

Recently my engine light came on, and we checked the code and it’s coming up for O2 sensor which makes sense since I’ve recently been seeing some performance issues that would likely be related (like lagging in acceleration, and trouble turning over on occasion but not always).

Anyway, family wants to do the repair themselves, and these home repairs have not ALWAYS gone well. I’ve watched a couple videos on YouTube and just want to see if anyone has any advice before I delve elbow deep into this mess and end up with a bigger problem?

Don’t tell me to just take it to a mechanic because that out of the question. Really I’m just looking for advice on what part to avoid/prefer, what might make this easier and what not to do. ?

Any help is appreciated, even if my stepdad probably won’t listen until it’s too late.

Well, first the HO2 sensor usually fails because of other problems (running rich, running lean, burning oil, etc.) so just throwing a sensor on it probably won't be the fix. I have a '02 1.8T Jetta. There is a spaghetti mess of vacuum and breather hoses on this thing. And all of it is know to be brittle and crack/leak.

I know you don't want to hear it, BUUUUUUUT this is the car to leave to someone who has done it before. DEFINITELY NOT A BACK YARD MECHANIC CAR. It will run worse, it will break down more, it will cost A LOT MORE to make it right after stepdad has monkeyed with it.

That said I have gotten "kits" with a lot of the common hoses and parts that fail for cheap and save $$$ over dealer prices. Just need someone who knows this engine to put it together.

Jason

I almost garuntee the problem is rust. It sat in a field for a while before I bought it and I don’t want to put a ton of money into it since I honestly don’t know how long it’s going to be mine. This is the only problem right now, and it needs regular maintenance before winter (tires, oil, etc) which I can barely afford right now with other things going on in my life. As it is right now it doesn’t leak anything and ran amazing before that engine light came on and I have absolutely no clue why that engine light came on. It came out of a field, and I put 50k km on it right quick for which it ran amazingly, and then the engine light came on and performance has gone drastically downhill since.

Really just want to solve the necessary problem and go from there. My stepdad is pretty handy with the American made cars but this is the first German made in the family and it’s proven more difficult but I’d still like to keep it out of a shop- I CAN NOT afford to put $600 into something we can possibly fix for $150.

If it is the sensor, this may help.

https://partsavatar.ca/product/bosch-oxygen-sensor-17014/3arxaj528n

Their prices are good, but in my experience, customer service should be improved.

boodles said:

.....................Really just want to solve the necessary problem and go from there..................

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Sure, and we'll try to advise best we can over this interweb thing. Just because the code says O2 sensor doesn't mean the sensor is the root problem. Seems odd you've have performance degradation just cause of a bad sensor, but who knows.
Get it high up in the air, soak it with PB Blaster or better, heat, bang, repeat. You may need the special socket to get good purchase.

Alchemist said:

If it is the sensor, this may help.

https://partsavatar.ca/product/bosch-oxygen-sensor-17014/3arxaj528n

Their prices are good, but in my experience, customer service should be improved.

Click to expand...

You think this is the part to replace?

BobnOH said:

Sure, and we'll try to advise best we can over this interweb thing. Just because the code says O2 sensor doesn't mean the sensor is the root problem. Seems odd you've have performance degradation just cause of a bad sensor, but who knows.
Get it high up in the air, soak it with PB Blaster or better, heat, bang, repeat. You may need the special socket to get good purchase.

Click to expand...

Well yea. I don’t know it seems to make sense to me. Trouble accelerating, trouble turning over always when the tank is emptier, rough idle, are all listed as symptoms of a bad sensor. If the engine hasn’t got what it needs, it makes complete sense no? If there’s no gas it’s not going to perform �� pretty sure it’s just nearly choking out all the time.

There are 2 sensors, so make sure you get the correct one. One before, and one after the first section of the catalyst, and they have different plugs to keep them on the correct circuit for the ECU.


If you do it when cold, the sensors should back out and screw in without too much horror, but since they are on top of the converter, you'll want to drop the down pipe. Either end will do so you don't really have to do both, but neither end will be easy. Due to heat and rust, even if the car were from Phoenix, it would still be rusted. Add in winter salt and lots more moisture, well... good luck as it will not be lots of fun. You can do it with patience and the afore mentioned PBBlaster to get the pipe down sufficiently to get to the O2 sensor(s).


Good luck,


PH

Thanks for the tip. Picked up the part today, going to dive in first thing tomorrow.

Kind of disappointed so many people are giving me flack for replacing an O2sensor. Most people are saying they aren’t worth replacing and my problems are clearly from something else. I’m pretty convinced that my problem is the sensor and just the sensor... but I guess we’ll find out tomorrow/over the next week or so if I blew $150 or if I was right all along.

boodles said:

Most people are saying they aren’t worth replacing

Click to expand...

Hmmmm... I think what some folks are trying to suggest that replacing an O2 sensor that's telling you it sees a problem may end up being like replacing a smoke detector because it is trying to tell you your house is on fire or got melted in the fire... ie the sensor may be doing its job.

Fingers crossed for ya, though.

Most opinions have been that they simply clear the codes and leave it be, or that faulty O2 sensors aren’t enough to actually affect the car. however I’ve read plenty blaming O2 sensors for exactly what my car has been doing, and clearing the code isn’t going to make the symptoms go away. I can’t just leave it, and if the O2 sensors are bad it’s going to affect the car, I’d rather waste $150 there than start throwing $500 at larger companants when the code reads sensor.

It’s the principle of parsimony.

Did anybody check the wiring for chewed up insulation. Since the car sat in a field for a year I would suspect rodent damage.

Rodents aren’t really a problem around here- snow is��

Well... the code was definitely for O2 sensor and I could see why when I got under the car, however I’m pretty sure this is going to be a slow and painful adventure as someone has evidently tinkered with this before. One sensor is definitely pooched and it’s clear someone tried to replace it and couldn’t and settled for repair- leaving both the cat and sensor in rough shape. Yay me.