OhRDX

So I have searched the hundreds of threads about bad O2 sensors and still cannot figure out what is wrong. I bought my '02 TL P with 160K a couple of months ago while the CEL was on. A quick scan showed O2 was bad.

I have done EGR and manifold cleaning (wasn't that bad), TB cleaning, new plugs, air filter, replaced both O2 sensors and still cannot get rid of the light. I have reset the CEL with port from Autozone, pulled the fuse, and unplugged the battery. After every time the light comes right back on. I have Bosch parts, and double checked that they are plugged in and nothing visible is wrong.
Cat seems to be working fine as well.

What else can I do to figure this out? Going to the dealership is not only a waste of money, but waiving the white flag and not something I want to do. I am out of ideas.

TLer trash

First, did you clear the code after you installed the sensors? The pcm won't supply a ground to complete the heater circuit if you haven't cleared the code(s). Second, some people have had bad luck with bosch o2 sensors. Ntk or denso are better, sometimes you have to go o.e. Make sure the application is absolutely correct. This is usually where the dealer listings are the most precise. As an example; I just bought o2 sensors for my wife's, and my daughter's cars, a00tlp, and an 03 tls. Rock auto has one number for the front, and one for the rear; the dealer lists 4 different sensors. Sometimes the differences are minimal, like lead length or color. Sometimes the differences are huge like a 12 ohm spec for a ulev car, and a 2 ohm spec for the sulev model. I think this code applies only to the rear sensor. Also check all your fuses.

OhRDX

I meant Denso. Bought both O2 sensors from rock auto.

I tried clearing everything after both sensors were replaced. I'll check all fuses, but would be surprised if I find anything. Thanks for ideas.

fsttyms1

I would start by checking the wiring for an open or short to ground in the wiring harness. Another thing to check/test is the coolant temp sensor. The ECU uses that to determine (based on coolant temp) that too much time elapsed before the oxygen sensor began operating properly.

OhRDX

How do I check the wiring for open or short? I can do almost all thing mechanical, but when it comes to electrical I'm screwed.

I do not think its the coolant temp. Sensor. The CEL lights up too quickly after resetting and starting the car for it to be that. After a reset it only takes about 3-5 seconds before light comes back on which leads me to believe its an electrical issue somewhere. If that is the case, what is the solution to that?

fabricator

Check you inbox,I sent you som troubleshooting.

OhRDX

Thanks!

This is what makes these communities great.

3.2TLc

Yeah, if ya find out ....let us know what ya did to fix it !!! Thanks.

JRhodes88

iTrader: (2)

I know this was a long time ago but what was the solution?

01tl4tl

neither of the members involved in the thread are active, ck their info
try fsttyms1