"engine Malfunction"

[steve_avensis_02]

I own an 02-plate Avensis 2.0CDX (petrol) - and, recently, it has been giving me _loads_ of grief. The car has done just 42K and has been religiously serviced at main-dealers.

The saga started September 2006 - I was late for work and, at reasonably high revs (though not red-lining) an orange picture of an engine appeared on my dash. The car continued to drive fine... so I called the main dealer and they had me take it in for a day... the answer 8 hours later was that it needed a new oxygen sensor... which, after two hire cars and one !Removed! expensive sensor set me back ~£400... but I considered the problem solved.

One week later the same light came on - this time at moderate revs (I wasn't rushing) and I angrily returned to the main dealer who I'd asked to fix the fault a week (and about 100 miles) previously. They said that the other sensor was faulty too (they hadn't told me there was more than one initially!) and this set me back a similar amount. I verified exactly what sensors had been replaced and have documents showing it to be the top right and top left (i.e. - as I understand it - the two sensors closest to the engine - hence the hottest - hence the most likely to fail.)

About two thousand miles and three months later, this morning, at modest revs/speed, the same warning light came on... and I'm _extremely_ suspicious that the oxygen sensors were not faulty in the first place... which makes me hesitant to return again to the same dealer who has twice failed to resolve the problem satisfactorily.

One thing that I find very curious is that I'd filled up from the same petrol station 10 miles prior to the warning light coming on for both most recent occasions - a Tescos Metro... and I'm wondering if this is in some way significant? I can't remember details about fuel immediately before the first problem.

Have others had a similar problem with their Avensis?

Can anyone tell me how likely it is that more oxygen sensors have failed on a car of this age and mileage?

Am I right to be suspicious that fitting a new oxygen sensor might be a lucrative task for the main dealer which doesn't actually address the real problem?

Is it credible to suspect that Tesco petrol is to blame? [i filled up with the cheapest unleaded... takes between ~50 and 52L - so, I guess, the tank has always had at least 8L left when I re-fuelled.]

Can anyone suggest something I can do to self-diagnose... or am I doomed to have to accept the word of a main-dealer with the equipment to read-off the fault codes?

To what extent should I worry that this might do further damage?

To guess my fuel consumption, my trip-computer gave a range of 340 miles when I last filled up. Is this usual? [Assume that I don't have a very efficient driving style. :-) ]

I've found a garage owned by someone else who specialise in Toyotas... Is there anything I can do to minimise the risk that I'm given bum information to encourage me to sign-off an unnecessary replacement parts which don't solve the problem?

[Starensis]

Well, I can honestly say you have been ripped off! £400 for an Oxygen sensor!! :censor:

They cost £70-£80 from Toyota & take 15 mins to change. I would question the garage as to why it's so much. What is on your bill?

I also had sensor go at 48,000 miles............ just after filling up with supermarket fuel. It was Sensor 1 Bank 2. You have 3 sensors in total, 2 at manifold & 1 post catalytic converter.

These are common sensors & can be purchased from internet for £60 ish.

Since I had mine go, I only use BP unleaded fuel. Car performs better & hopefully will not knock out one of my sensors. So far, so good.

My advise is find a garage you can trust ( does not have to be main dealer ) & stick with them. Providing they can read fault codes, repairs should be straight forward. Try to arrange a price before they start any work. Once they have read the code they should be able to give you one easily. Don't accept first price though.

[chrisstyles]

If you are in to dabbling yourself, you can buy a connector and software over the internet which will tell you which oxygen sensor has failed. Thats assuming your avensis supports the OBD interface. You can then buy one over t'internet as starensis says. Worth a google.

[steve_avensis_02]

Well, I can honestly say you have been ripped off! £400 for an Oxygen sensor!! :censor:

Well, to be honest, the price rose significantly as I had to get it done during the working week - so that cost "to me" includes, for each sensor, the price of two hire cars; delivery and collection for each - all at "last minute" maximum prices. I think it was about £250+VAT just to "do" each sensor if I could have hung about for two half-days... but I couldn't.

I also had sensor go at 48,000 miles............ just after filling up with supermarket fuel. It was Sensor 1 Bank 2. You have 3 sensors in total, 2 at manifold & 1 post catalytic converter.

I've paid (so far) to do both of the manifold sensors... so, if this is a sensor... it has to be the one post catalytic converter... unless one of the sensors already fitted was faulty... or work wasn't done. The main-dealer actually told me that there were two manifold sensors - and two later... just one does make more sense.

These are common sensors & can be purchased from internet for £60 ish.

So, if it is a sensor, I should be hoping to pay no-more than around £150 - to allow a reasonable profit margin... I hope. :-) I don't have time or equipment to attempt this myself these days... unless, of course, it is a _very_ easy job.

Since I had mine go, I only use BP unleaded fuel. Car performs better & hopefully will not knock out one of my sensors. So far, so good.

Is it known that some types of fuel are more likely to cause problems? I use Tesco only because it is convenient - they own the three stations I actually pass on a regular basis! Why should performance improve with BP fuel?

My advise is find a garage you can trust ( does not have to be main dealer ) & stick with them. Providing they can read fault codes, repairs should be straight forward. Try to arrange a price before they start any work. Once they have read the code they should be able to give you one easily. Don't accept first price though.

Well, if I assume that the expensive main-dealer garage I've used for the first two sensors isn't a good choice, then I've got my work cut out. I refuse to use the closest main dealer as I think, but can't prove, they defrauded me over an extended warranty and definitely weaseled-out of another honest warranty claim that, in my opinion, should have been covered - "because they could" - as well as giving contradictory quotes about "essential work" - and, to top it off, under a different trading name - at a different address - sold to someone else a car they had already sold to me (deposit paid!) The second nearest main-dealer I'd assumed was just expensive - but it now seems also incapable of resolving the root problems! A third main dealer around here entirely failed to instil confidence when I reported an intermittent faulty handbrake... they insisted it was "all in my imagination" - then it failed completely at a junction on a steep hill on my way home!

I've found an "independent" Volvo/Toyota place - and, as it seems I need the fault codes read, I'll give them a try. It is a pain in the backside that I seem to be travelling further and further afield to find someone honest and capable. Hrrumph!

[Starensis]

As far as I'm concerned they should only charge the following:-

Diagnosis = 15 mins, change sensor = 20 mins. Therefore labour should cost £45 at most & sensor £60.

Add the dreaded VAT & should cost around £125, main dealer.

Non dealer should be alot cheaper than that. The family run garage will also possibly do a better job as their reputation is at stake.

Get the code read first before you make any assumptions. Sensors do need replacing after every 50k ( ish ).

Believe me it IS a very easy job!! You just need 22mm ring spanner & ability to disconnect & reconnect connector.

Not sure why BP fuel is better. They do add additives to their fuel which may help the engine run cleaner & not :censor: up the sensors. BP fuel is not far off Supermarket prices anyway.

Don't forget to ask them for a price after they have read the codes. If they can't give you a reasonable price, ask them for the code ( I have a list of what they relate to ) & pay them for there 10 mins of work, then walk away.

[silverarrow]

clean your maf and use fuel injector cleaner comma and keep revs up for a half a tank of fuel

[steve_avensis_02]

clean your maf and use...

Please forgive my ignorance... What is a maf?

I've made some progress... The main dealer wants to charge me £150 for the sensor; £37.50 for diagnosis (a prerequisite to starting the job) and a further £75 to fit it. So... ~£278.50+VAT this time from the main dealer - per sensor.

I've managed to get the car hooked up to a diagnostics unit for free (with a bit of wrangling) and it says "Bank 2 sensor 2" - which Is one of my two remaining original sensors - according to the mechanic.

Having had three of my four sensors fail in the last 3 months, I suspect that the fourth is likely to follow suit soon too... so, I'm thinking that maybe I should replace both remaining sensors to avoid having my car inconveniently back in the garage in a week or two's time... but... this - obviously - gets expensive at main dealer prices!

I'm finding that generic "Lambda" sensors sell for about £30->£50 on the internet - and, while I didn't want to be bothered, I am capable of changing spark plugs - and this doesn't look much more difficult... if I can identify a suitable generic replacement. It seems that most places don't say that their sensors are compatible with the 2.0VVTI engine... I wonder what, if anything, is so different about my car's Oxygen sensors?

Would I be right in thinking that I can double-check the diagnosis by using a digital multimeter on the sensor in question? Would I be right in thinking that I should get a resistance reading of ~30 ohms across the heating element (engine off/cold) - and somewhere between 0 and 1 volt across the sensor itself when the engine is running?

[Starensis]

Check this site out Lambda sensors

It will provide you with most of the info you need.

[steve_avensis_02]

Check this site out Lambda sensors

Thanks...

I've read all their stuff... but they don't list any 2.0 Avensis engines - just the 1.6.

I've emailed them now though...

I need sensors for the 2.0VVTI one... Interesting general information though...

Steve

[Starensis]

All you need to know is if your sensor is 4,3 or 2-wire. Your's is 4-wire & usually has 2 black, Blue & white wires.

All 4-wire sensors are heated. All you need is 4-wire & the site listed will show you how to rewire. I used a Ford sensor on mine & just swapped the wires around. They all work the same way!

[steve_avensis_02]

All you need to know is if your sensor is 4,3 or 2-wire. Your's is 4-wire & usually has 2 black, Blue & white wires.

My sensors are definitely 4-wire and have two black (top of connector) and one white and one blue (bottom of connector)... just like in the wiring diagram on www.lambdasensor.com Acording to that site, however, there are four different kinds of sensor on the market - all of which are available in 4-wire 18mm form... and I assume 18mm form with "no flange" would be right for the 2.0vvti Avensis?

(1)Zirconia 'thimble' type

Heater resistance: 2 to 6.5 ohms

Output signal: oscillating 0.1 and 0.9 volts

(2)Zirconia thick film type

Heater resistance: 12 to 15 ohms

Output signal: oscillating between 0.1 and 0.9 volts

(3)Titania

Heater resistance - 4 to 7 ohms.

Output signal - oscillating between 0 and 1 volt or between 0 and 5 volts (depending on make and number of wires)

(4)Lean Burn

Heater resistance - 12 to 15 ohms

Output signal - discrete voltage levels between 0 and 5 volts

This is what left me uncertain about "type" of sensor... I should be able to distinguish between types 1 and 2 by measuring the resistance of one of my "known-good" sensors... checking to see if the heater resistance is above 10ohms. I've a good digital multimeter I've not used for years... I expect I should be able to identify if a sensor is reading above 1volt too... which would indicate that it must be a type (3) or (4)... Getting the output voltage range wrong would likely be a problem - in either direction.

I'm guessing that it is a good idea to have matched sensors? I'd expect there to be some margin for variation... but does it matter (aside from output voltage range) which kind of sensor above I use? Several suppliers talk about a "Universal sensor" - which I've assumed, so far, would be of the 1st kind?

[theresa]

Hi guys, please advise a helpless female owner of Avensis. The wretched diagnostic light on the dashboard came out of the blue. Local garage claimed to have decoded the fault as some mysterious PO115. They charged me £75 for engine code testing and £15 for cleaning engine sensors (?) by ways of putting in some fuel treatment. The light went off but by the time I drove the car back home - some 2 miles - the light was back on. What is the mysterious PO115 and what do I do about it ?????

[taxigeoff]

Hi guys, please advise a helpless female owner of Avensis. The wretched diagnostic light on the dashboard came out of the blue. Local garage claimed to have decoded the fault as some mysterious PO115. They charged me £75 for engine code testing and £15 for cleaning engine sensors (?) by ways of putting in some fuel treatment. The light went off but by the time I drove the car back home - some 2 miles - the light was back on. What is the mysterious PO115 and what do I do about it ?????

P0115 is engine coolant temperature circuit. Probably a bad connection.

[theresa]

Hi guys, please advise a helpless female owner of Avensis. The wretched diagnostic light on the dashboard came out of the blue. Local garage claimed to have decoded the fault as some mysterious PO115. They charged me £75 for engine code testing and £15 for cleaning engine sensors (?) by ways of putting in some fuel treatment. The light went off but by the time I drove the car back home - some 2 miles - the light was back on. What is the mysterious PO115 and what do I do about it ?????

P0115 is engine coolant temperature circuit. Probably a bad connection.

Thanks for a prompt reply. I thought it must be more specific than 'engin sensor'. Will try to get it attended to.

[Avensis luna 03]

clean your maf and use fuel injector cleaner comma and keep revs up for a half a tank of fuel

Where exactly is the MAF located specifically in the 1.6 Lean burn engine fitted to a 99 Avensis? Thanks for any pointers.

[silverarrow]

READ MY COMMENTS NEW CAT ECU KNOWN FAULT TOYOTA HAVE ATSB RE THIS ISSUE !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

JUST LIKE THE DUFF VVTI ENGINES AND HIGH OIL CONSUMPTION