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Nemo2000

Rav4 Engine Warning Light Issues

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We have a 2000/01 (X-reg) RAV4 NRG. Suddenly it is beginning to cost us LOTS of money :-(

Earlier this year the yellow engine warning light came on - manual said 'take to dealer'. He plugged in his diagnostic computer and within 15 mins was able to tell us that it was an error code **** which meant a faulty air/fuel emissions sensor. Simply for telling us what was wrong he charged us £45 + VAT! He suggested that it might be a 'blip', one possible cause apparently being water in the fuel (we had filled the tank about 10 miles previously), so he re-set the light and suggested that we drove it about for a while to see what happened. Sadly the light re-occurred, so we took the car back to have the sensor replaced - about £260-ish :-(

FIFTEEN miles later the light came on again. Another diagnostic - another fee - this time a DIFFERENT sensor. Apparently there are FOUR of them and it is not unknown (allegedly) for 2, 3 or even all 4 to fail in quick succession. So - we tried it again for a while, but the light came back on - so, another diagnostic and another £260-ish for another sensor.

Yes, you've guessed it - today the light came on again - about 2 miles after filling up with petrol. So, it's back to the dealer this week for more diagnostics - what's the betting it's the 3rd sensor now???? And will that mean the 4th one is not far behind?

My gripe is - surely there must be a better way of managing these warnings? If every error condition has a pre-defined code number, why not get the car computer to display the code and let the user look it up in a table in the car manual to decide for themselves how serious the situation is - eg if I'm doing 70MPH down the motorway in the middle of a 150-mile round trip, is it quite safe to wait until I get home or do I need to summon help now? How do I know if I've got the same problem again, or something completely different and potentially more serious?

Once the light comes on it stays on, even apparently if the problem goes away, it has to be reset by the dealer. Why not have a 'light reset' button for the driver? If I press that and the light doesn't come back on again within a few miles, then I can breath a sigh of relief. Instead, I have to go to the dealer and pay yet another fee. How many times do I do this - and he pockets the money - before it is decided that it really is a fault and not just a 'blip' cause by wet petrol etc????

[ While all this was going on, we had the car serviced recently and it needed new front discs, as they were worn below minimum thickness. At the same time they fitted new front pads, so altogether about £325-odd if I recall. The annoying bit - we only had new front pads last year anyway, since when they've only done about 6K miles <grrr>. ]

This car is beginning to seem like a "cash cow" for the dealer !

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This car is beginning to seem like a "cash cow" for the dealer !

Indeed - my Engine Management Light came on literally as I was driving passed the dealer! - I think they have a wireless remote control for switching on the light when they need some revenue!

In the good old days, you drive the car until you heard a strange noise or it stopped! Now the ECU can check everything every few miliseconds - so its bound to find more faults, I don't need that, thanks!

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As the more learned members come on they will be able to tell you how you can read your fault codes yourself

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You can read the codes and you can cancel them yourself but you have to say before you go to the dealer :thumbsup:

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Am I right in saying the fault code system on this car would be before the OBD interface.... so its a technical bent paperclip and bulb answer to count the number of flashes?? Which in my opinion is relatively primitive.

Although in saying that, I run the racing rav with the engine light always on - if it goes out I have problems!! Due to it being a totally hybrid set up with a programmable ecu - non-Toyota.

On the brake disc problem, its unusual to fit new discs without fitting new pads...partly as the pads will have bedded into the shape of the old disc. However the price you paid is way above what it could have been done for. Basically a disc is a disc so you can buy elsewhere and use Toyota pads.... and as its a simple job, then any decent mechanic or garage can do the work instead of a dealer. well known that dealers survive by replacing discs. Bet you didn't get the old discs back! (worth a little in scrap metal).

What's the mileage on the car?

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And if there's no warning light it doesn't mean everything is OK. Just that the diagnostics don't recognise it.

My engine management light did reset itself, maybe that's an improvement on the 2005 diesel engine over yours :rolleyes:

It sounds like one of the OBD readers would be a sound investment for you!

AFAIK brake discs need to be replaced much more often than of old due to them not being able to use asbestos in the pads. I'd have thought a couple of emergency braking applications would have ground off any high points on the pads. Unless they worn disc had contaminated them and that's why they needed replacing.

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You can read the codes and you can cancel them yourself but you have to say before you go to the dealer :thumbsup:

Really? Never knew that Anchorman. How much would one of these units cost or is it a case of making a board up using components?

Thanks

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You can read the codes and you can cancel them yourself but you have to say before you go to the dealer :thumbsup:

Really? Never knew that Anchorman. How much would one of these units cost or is it a case of making a board up using components?

Thanks

Seen this: http://www.toyotaownersclub.com/forums/index.php?showtopic=116911 :thumbsup:

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And if there's no warning light it doesn't mean everything is OK. Just that the diagnostics don't recognise it.

My engine management light did reset itself, maybe that's an improvement on the 2005 diesel engine over yours :rolleyes:

It sounds like one of the OBD readers would be a sound investment for you!

AFAIK brake discs need to be replaced much more often than of old due to them not being able to use asbestos in the pads. I'd have thought a couple of emergency braking applications would have ground off any high points on the pads. Unless they worn disc had contaminated them and that's why they needed replacing.

Easier than that, following a recommendation on another thread I've just ordered one of these, I recon it will very quickly pay for itself now I'll know when dealer is trying it on...

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=150403709077&ssPageName=STRK:MEWNX:IT#ht_2932wt_991

Obviously I've not tried it yet...

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And if there's no warning light it doesn't mean everything is OK. Just that the diagnostics don't recognise it.

My engine management light did reset itself, maybe that's an improvement on the 2005 diesel engine over yours :rolleyes:

It sounds like one of the OBD readers would be a sound investment for you!

AFAIK brake discs need to be replaced much more often than of old due to them not being able to use asbestos in the pads. I'd have thought a couple of emergency braking applications would have ground off any high points on the pads. Unless they worn disc had contaminated them and that's why they needed replacing.

Easier than that, following a recommendation on another thread I've just ordered one of these, I recon it will very quickly pay for itself now I'll know when dealer is trying it on...

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=150403709077&ssPageName=STRK:MEWNX:IT#ht_2932wt_991

Obviously I've not tried it yet...

i have this 'U480 Diagnostic Scanner CAN OBD2 EOBDII Code Reader' for some years now and it has paid it self back more then once!

did last week a volvo from my neightbour :yahoo:

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You have to watch the age. Petrols from about 2001 and diesels from about late 2003 are OBD compliant but if you have a car on the changeover date you will end up selling it or keeping it for future use as all cars share the same compatibilty.

You can get the car to flash the code back as bothy says. You connect a paper clip across 2 of the terminals then count the flashes. In this case, 4 long flashes and one short would be telling you the early 2 digit code - 4.1. These days they give out OBD standard 4 digit codes but they can be read in the same way. Luke 4X4 will chunner at me for even suggesting it and he is right that you can spike the ECU if you get it wrong. One of these days I will do a tutorial to show the process but time is at a premium these days!

I will attach the pdf showing the different methods when I get the chance.

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Luke 4X4 will chunner at me for even suggesting it and he is right that you can spike the ECU if you get it wrong.

I remember seeing Luke's posts at the time and had to "bite my keyboard". To be honest I think it is an over-reaction and have to disagree.

Nearly every ECU is designed to take what effectively amounts to indefinite shorts to vehicle supply and ground on all of its input/outputs. Then it is also designed to take a whole suite of voltage transients applied to its pins. Some of these are a few hundred volts (but quite short in duration). Others are a hundred volts or so, but a bit longer. During testing these pulses are applied for hours at a time, without damage.

On top of that, they have to survive ESD (ElectroStatic Discharge) pulses to probably 8kV or more.

Toyota's specs are no less severe than anybody elses in this respect.

Yes, by all means take care when connecting wires, but if you should make a mistake, you are unlikely to do any permanent damage.

Everything that comes into the diagnostic connector will have the above level of protection.

You could I suppose do something like short a CAN bus out, which is likely to throw a load of DTCs in many ECUs - which may have been what Luke was concerned about. It shouldn't really do any permanent damage. OK, electronic components do suffer from age related problems, which combined with abuse could potentially kill something, but, that is considered at design time....................

However, don't assume if you buy an aftermarket accessory it will have the same level of protection. I've taken many apart and it's clear very often that the designers do not fully appreciate all the stuff a vehicle electrical system (or user) can throw at it.

It's tempting fate, but how often do we see true ECU faults on here? We seem to get 4.1 alarm problems (old, aftermarket support not available), 4.2 auto gearbox ECUs (sounds like a genuine design fault to me - it happens, just as it does with mechanical components) and possibly people would count lambda sensors (but those are in a very hostle environment and will always fail eventually). I think that says something about the general robustness of these things.

Ok, I feel better now :D. Maybe prepare for incoming..............................

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Ma boy :thumbsup:

When it comes to electrics, if this man says red is blue then I say what shade of blue is it shcm?

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Well, got the results back today from the dealer. You've guessed it, it's another oxygen sensor fault and NOT the one previously replaced. The RAV is X-plate, registered late 2000 and done about 36000 miles. The codes being quoted to me are all 4-digit ones.

We are thinking now of taking a calculated risk and - on the assumption that probably the 4th sensor will fail in due course - getting it replaced at the same time, in order to save money on even more diagnostics and labour. Any views on that?

Comments from the dealer vary as to the cause, suggestions being 'age' and the possibility of damage from 'poor fuel'. Having just filled up the tank only about 2 miles before the light came on (!), I'm tempted to keep driving it until almost all that tank is used up before getting the sensor(s) replaced. So that will be quite a few miles with a faulty sensor - is that likely to cause any problems?

The irony is - this car is 10 years old and mine (not a RAV) is 12 years old. Both are beginning to cost money to keep running and really we only need one car now, so we have been planning to get rid of both and get one new(ish) one. The thing is, for various reasons we don't want to have to bother with that particular issue until next spring, but how much more cash will we have to keep expending in the meantime??? Groan....

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Not really much I can say about this - its the joys of motoring. Its one of those things; you will sort it all out then make a damn good car for somebody else if you flog it after.

Unfrotunately these confounded oxy sensors do sometimes all croak in quick succession. I would do them as they fail but you could do yourself a big favour and buy an OBD reader instead of going back to a dealer.

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Good grief Nemo2000 you've had some bad luck with the car i would be peed off too,get yourself a code reader and relax in the thought that not much else can surely go wrong :D

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A further quick question - would disconnection of the Battery reset the engine warning light and the error code? Is there anyway to know if I am getting fresh error, rather than simply the after-effect of the previous error?

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It will reset the light but it may store an old code. Shcm will be able to answer that best as he eats ECUs for breakfast.

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I thought that fruit and fibre was a bit tough this morning.

Right, I've seen claims before that "disconnecting the Battery will clear all the faults from an ECU".

I've been involved with the design of the things for a fair while (sometimes it seems too long :D), and I have to say I don't really ever remember any ECU not have some form of non-volatile memory (i.e. an area where it can remember things - even if the power is removed). Perhaps some of the units in production didn't 20 odd years ago when I joined the industry, but I really can't remember :blink:

There are a number of fault storing strategies. Some common scenarios are (not all):

The light comes on if the fault occurs in the present "powered up" cycle, but doesn't come on if the fault has cleared the next time around. The fault is probably still stored though regardless.

Sometimes (depending on the considered seriousness of the fault), if the fault has not been detected for say 10 "power up" cycles it will be cleared.

Not every fault stored will turn on the fault lamp.

Sometimes, there will also be "snapshot" data stored with the fault. i.e. say various sensor condition under which the fault occurred.

Generally, the only sure way to do what you want is to read out all the fault codes, clear all the faults and see if it then re-occurs later.

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OK thanks. Then I'll go back to my previous question - will driving the car around for (say) a couple of hundred miles to use up most of the current tank-full of petrol BEFORE I get the sensor changed cause any problem/damage?

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I'm not sure if there is any benefit but it won't harm.

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It has taken 500 miles for my engine check light to come back on, by which time my U480 had arrived, so I was almost pleased that I had a code to read.

Yes it it P0420, so I reset it just to proves the new toy works!

Dealer has still not worked out how to download the s/w update....

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Well, I disconnected the Battery and put it on charge overnight while I had the chance. When the Battery was reconnected today and the engine started the light stayed off - however, I shall have to wait and see what happens after it's been driven about for a while.

In the meantime....I've been reading more on the thread about code readers. This may seem obvious to those in the know, but having read the code how do I decipher what it means? Do the readers contain built-in de-code information, or does the detail have to be looked up somewhere else? And...just to ask the blindingly obvious question - whereabouts in the car do I actually plug the thing in ?? :unsure:

From my experience so far I now know three of the sensors codes from the dealar's reports, but not the fourth (yet!).

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Some just read the number and you decipher it out of a book and some have the info come up on the display. Some codes are Toyota specific so you have to come on here and ask :thumbsup:

The plug is just by the bonnet pull. Not all RAVs are compatible and I think yours is just on the changeover date.

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"The plug is just by the bonnet pull. Not all RAVs are compatible and I think yours is just on the changeover date."

I had a look under the dashboard just behind the bonnet pull and there is a 16-way (2 x 8) white plastic socket - is that it? Does that tell if it is compatible or not please?

Well, I managed just 3 (!!) miles before the light came on again <grrr>. Anyway, I've stuck black tape over it for the time being so that I don't have to look at the d*** thing shining all the time!

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