O2 Sensor Question

[Benlake]

Hi

After changing my exhaust for a sports cat I picked up a P0141 error code.

Just wondered if I can use my spare pre cat sensor which was left over from my 2zz conversion?

The faulty one is post cat and my spare one is pre cat, they do look a bit different (pre cat one has a fatter end) but thought I might check before shelling out on a brand new one.

I thought it was odd that it was suddenly faulty after working fine for 2-3 years since I did the conversion.

[Call the midlife!]

Theoretically they should be the same sensor, just the post cat needs longer wires than the two manifold cats.

[1979scotte]

Disturbing O2 sensors on the 2 does seem to upset them.

What cat did you fit 400cel 200 100???
Is the sensor definitely FUBAR and not just giving a code because your cat is far less restrictive?

[Ardent]

@Benlake

As above.
And, before shelling out. Maybe, Reset the code and monitor.

Do you have a obd dongle and torque Pro, just so you can see it is completely gone, or just the heater part.

[Benlake]

The cat is 200 cell the previous was pipe with no cat in at all.

I check it was tightened up nicely, it is a bit white near the screw end maybe some water got in? Yeah it would be really annoying to buy a new one and get the same code!

Cat has gotten more restrictive than before I hoped the ECU would just deal with it but seems a little unhappy about something.

[Benlake]

Just have a standard reader its a hand held plug in one Fox something

[Ardent]

Ideal for code reading.
But for not many wine tokens, a dongle and  torque Pro opens up a lot more info.

If you are an apple user, will cost more tokens. Something to do with Bluetooth standards or something

[1979scotte]

The cat is 200 cell the previous was pipe with no cat in at all.

I check it was tightened up nicely, it is a bit white near the screw end maybe some water got in? Yeah it would be really annoying to buy a new one and get the same code!

Cat has gotten more restrictive than before I hoped the ECU would just deal with it but seems a little unhappy about something.

Did it have a defouler fitted on the 02 sensor?
I thought running without a cat would throw a code without one?

[paulj]

If you are an apple user, will cost more tokens. Something to do with Bluetooth standards or something

Choosing a WiFi connected dongle will bypass a lot of the fruit based Bluetooth woes, and keep spare tokens available for wine

[1979scotte]

If you are an apple user, will cost more tokens. Something to do with Bluetooth standards or something

Choosing a WiFi connected dongle will bypass a lot of the fruit based Bluetooth woes, and keep spare tokens available for wine

But it's a ball ache because it removes your Internet connection for instantanuous code look ups.

[paulj]

Good point.  I use auto doctor app and that one holds over 18,000 codes in the app to help overcome this!

[Benlake]

The cat is 200 cell the previous was pipe with no cat in at all.

I check it was tightened up nicely, it is a bit white near the screw end maybe some water got in? Yeah it would be really annoying to buy a new one and get the same code!

Cat has gotten more restrictive than before I hoped the ECU would just deal with it but seems a little unhappy about something.

Did it have a defouler fitted on the 02 sensor?
I thought running without a cat would throw a code without one?

Yep it gave me the cat problem code after the conversion I bought a little screw in extension it just pulled the sniffer end out far enough to keep mr ecu happy

[1979scotte]

The cat is 200 cell the previous was pipe with no cat in at all.

I check it was tightened up nicely, it is a bit white near the screw end maybe some water got in? Yeah it would be really annoying to buy a new one and get the same code!

Cat has gotten more restrictive than before I hoped the ECU would just deal with it but seems a little unhappy about something.

Did it have a defouler fitted on the 02 sensor?
I thought running without a cat would throw a code without one?

Yep it gave me the cat problem code after the conversion I bought a little screw in extension it just pulled the sniffer end out far enough to keep mr ecu happy

Have you removed that now then?

[Benlake]

Yes its still attached to the old decat mid pipe. I fitted my spare o2 sensor and cleared the code will run it for a while and see if it comes back.
Was planning on swapping mid pipes quite frequently for track days and then swap back for road use, as only took me 30 mins to swap them.

[1979scotte]

Yes its still attached to the old decat mid pipe. I fitted my spare o2 sensor and cleared the code will run it for a while and see if it comes back.
Was planning on swapping mid pipes quite frequently for track days and then swap back for road use, as only took me 30 mins to swap them.

Eery time you change pipe there is a chance it will throw a wobbler.
I've never had any 02 sensor issues but that's what people seem to think.
I don't think I'd bother either stay with the decat and just swap for MOT or keep the cat.
If you're running stock 2zz ECU really don't think the minimal performance increase is worth the hassle.

[Benlake]

Yeah I might have just bought the cat version first time round with hindsight.

It is interesting comparing the two pipes though, the cat actually feels better lower down the rev range but it's definitely lacking power at the top end when in lift.

[JB21]

P0141 error code is a heater circuit fault. If its post cat and you don't need an MOT anytime soon, just leave it as its not doing any harm to the running of the car.

You can also use a multimeter to check the resistance, could be both sensors are shot.

[Benlake]

Thanks will try that, if the code comes back I'll prob by a new sensor. I don't like running with codes as might miss a bigger problem.

[Benlake]

Ended up buying a new sensor seems to have done the trick.

[Mr2paul]

I just got a plug in reader for £25 and it does the job for me. Reset code and ran through some cataclean as Gazmrs suggested and all is well for me.