Oxygen Sensor - Help Me Understand

[onestar]

Hi All, again,

I posted this question last month, but to recap

Engine Light went on: Dealer for £40 said Oxygen Sensor 1 Bank 2 needs replacing: They Reset Light:

Engine Light went on: After a few miles of reset.

Engine Light went off: After two days.

Engine Light stayed off - so I cancelled the booked appointment (£350) and simply purchased the part £150.

Almost one month later light went on - On the way home, at almost the same spot.

I had bought the gendan pc diagnostics, and it said P0155, Sensor 1, Bank 2 had a heating fault.

However from the diagnostics sensor 1 bank 1 & 2 seem to working correctly - oscillating in tandem.

Sensor 2 bank 1, seems steady state high, until I de-accelerate from acceleration then it drops, and goes back up.

The fault code says I was doing 25mph (it said that the last time too!!)

So I reset the light this morning. It still off.

SO MY QUESTION :)

What the **** is going on.

Is this a ready to fail component ?

Is this something to do with the petrol I fill up with ?

Is this my driving ?

Is there something else that causes this ?

I just don't want to spend £200 to replace in labour charges (they claim its jammed and needs the manifold removed to avoid damage) - unless I really need to.

[davemh]

This may not answer your questions, but may help

About 2 years ago confronted with sudden poor running engine & an engine fault indication I was advised by Toyota to stop using supermarket fuel, since borne out by the recent problems with Tesco et all.

Since then I have stuck to branded fuels such as Shell, Esso etc. but have occasionally still had an engine warning indication & rough running, (fault code P1215 = EDU circuit ) but always soon after the tank has been filled to maximum. (within minutes)

Switching off the ignition & restarting returns the engine to normal running, & disconnecting the Battery for about 10 minutes resets the warning light.

I've been advised that I can expect oxygen sensor problem as the car has over 60K miles on the clock.

The latest event (again soon after a fill up) indicated a “malfunction of oxygen sensor” (fault code P0135) bank 1 sensor 1. Which was found to have an open circuit heater.

What I need to know is can I assume that both No. 1 sensors, ie bank 1 & bank 2, are the same.

[Cypermethrin]

The 'mare I had with the sensor in my '53 2.0vvti was only cured by getting the engine de-coked

And this after escalating the repeated O2 lights to the Toyota Group Service Manager

Since getting it decoked has been fine (> 8months) - before was going every 3 months

Local toyota dealer said it was down to how I drove the car - such an incredibly beautiful personts.

[Cypermethrin]

How off the last phase in my post above "such an incredibly beautiful personts" was inserted automatically in response to me referring to the dealer as something quite derogatory !

[silverarrow]

long standing problem with high miles on engine and low sulphur fuels and lack of lubrication.

Even toyota add fuel cleaner with a major service.

Read honest john from daily telegraph and known issue with need for new cat ecu and modified software.

^_^

[DTO]

What type of driving style creates the coking of the engine?

[Beagh1958]

I recently had cause to pull head of my D4D. Upon changing Glow-Plugs as i removed the first 2 plugs, no tips the part that glows red hot when using cold start. Nightmare time head off very time consuming job, previous owner had fitted after market components. Tips to large for drillings in head thus tips jammed in head. But this relates somewhat to your problem, I have allways put the best fuel into tank & a couple of times each year had used cleaning fluids to run through system. I'm afraid no matter how modern & clean fuels are carbon buildup is a natural proces of the 4 stroke engine cycle. I was amazed at the amount of carbon in & around cylinder head components,valves, inlet manifold etc etc. It is just a fact that people no longer think that to remove a cyl/head & give it a complete de-coke is required. New fuels may reduce carbon build up, but if head is never removed for any reason it will still be like engines from the past completey bunged up with carbon after a certain amount of milage has been put on car. Another way of keeping your cats & o2 sensors in fine working oreder is to thrash the living daylights out of your engine on ocassion, which allows your cats to really get up to some really seriously high tempertures & allows them to work as they should, just don't park on grass afterwards. Sounds brutal on engine & may sound like i am condoning breaking of speed limit but it does the trick.