O2 Sensor Issue, Or Maybe Not?

[steve_avensis_02]

I'm being driven mad by recurring oxygen sensor problems - over the last year I've spent about the same on oxygen sensors as fuel!!!

I've had three replaced, and a week ago the warning light came on again... I went to the main dealer - they said that "it must be a faulty sensor £250, please..." "Which one?" "Bank 1 sensor 1" "Oh. that one you replaced 10 months ago?" "Ah. yes, we can do that under parts warranty... we'll order in a replacement... we've reset the engine management unit - and the light has gone out - it will probably be fine for another few thousand miles... but we can fix the sensor under warranty if you bring the car in next week... On the way home (2 miles!) the warning light came on again... and I pressed them to book it in ASAP... Today I've been back; dropped off the car; wandered around for three hours - returned... sensor replaced, they say "you shouldn't have any more trouble - the warning light is out." I get three quarters of the way home... and, guess what - the light is on again! I return to the garage - and they say the fault code says it is "Sensor 1, bank 1".

Now, while I'm no mechanic, I smell a rat. The car hasn't yet done 50K miles - and bank 1 sensor 1 seems to be remarkably unfit for purpose if one sensor does < 10K miles before it is dead - and another under two miles... I strongly suspect that this is not an oxygen sensor fault at all... it seems far more likely to me that the engine management computer has dirt on its contacts, or a contact is corroded - or something. The snag - it seems my local toyota garage doesn't know what to do if replacing the part their diagnostic unit tells them to replace doesn't fix the fault.

Can anyone here give me a hint about where to look to see if there is a bad connection?

[steve_avensis_02]

Whoops, forgot to mention - it is a 2002 (02 plate) 2.0 CDX (petrol) - it has four oxygen sensors.

[rosecott]

I posted a similar problem a few days ago. Has there been any progress with your problem? I'm back at the Toyota dealer Monday morning for another go at the diagnostics. As I said on my posting, my new oxygen sensor lasted 3 miles before the dreaded orange light re-appeared.

[pmb]

That's interesting as my Rav4 had that sensor replaced in May. Twice in the last month the light has come on but cleared after a day or two.

[moonstone mart]

Possible manivertor then, alot more expensive than a sensor though :(

Mart

[Roger H]

I'm being driven mad by recurring oxygen sensor problems - over the last year I've spent about the same on oxygen sensors as fuel!!!

I've had three replaced, and a week ago the warning light came on again... I went to the main dealer - they said that "it must be a faulty sensor £250, please..." "Which one?" "Bank 1 sensor 1" "Oh. that one you replaced 10 months ago?" "Ah. yes, we can do that under parts warranty... we'll order in a replacement... we've reset the engine management unit - and the light has gone out - it will probably be fine for another few thousand miles... but we can fix the sensor under warranty if you bring the car in next week... On the way home (2 miles!) the warning light came on again... and I pressed them to book it in ASAP... Today I've been back; dropped off the car; wandered around for three hours - returned... sensor replaced, they say "you shouldn't have any more trouble - the warning light is out." I get three quarters of the way home... and, guess what - the light is on again! I return to the garage - and they say the fault code says it is "Sensor 1, bank 1".

Now, while I'm no mechanic, I smell a rat. The car hasn't yet done 50K miles - and bank 1 sensor 1 seems to be remarkably unfit for purpose if one sensor does < 10K miles before it is dead - and another under two miles... I strongly suspect that this is not an oxygen sensor fault at all... it seems far more likely to me that the engine management computer has dirt on its contacts, or a contact is corroded - or something. The snag - it seems my local toyota garage doesn't know what to do if replacing the part their diagnostic unit tells them to replace doesn't fix the fault.

Can anyone here give me a hint about where to look to see if there is a bad connection?

Had exactly the same problem with mine but I got away with having to change the sensors as my local garage had the correct test set to check them.It then failed the MOT for emmisions and I had no choice but to take it to Mr T who were baffled. It took them 8 days (and me £374) to eventually change the Mass Airflow Sensor,according to their Service Manager some MAF problems don't show up on the diagnostic computer and they ended up swapping bits off other cars until the fault cleared.It seems to have worked as the dreaded orange light has stayed off since then although it only just passed the next MOT on emmisions - probably due to the vast quantity of oil it is consuming.

[uumode]

If the mechanics really can't find anything wrong with the sensors, and you haven't changed your Battery for about 3 years, it could be a slightly underpar Battery that is triggering sensitive warning lights (if the warning lights aren't on all the time). Although when measured using a Battery meter it appears OK, the hypersensitivity of warning systems can pick up on a less than healthy battery.

[pmb]

That's possible uumode with mine as it's the original Battery. It has come on again today - may try charging the Battery in the short term as it did clear after a run on the previous occasions.

[rosecott]

The latest in my saga is that, having again run the diagnostics with the same result that it's the sensor they already changed, they have ordered another new sensor which they will replace without charge - watch this space.

[rosecott]

Toyota dealer fitted new sensor in 20 minutes at no charge. Orange light is no more.