O2 sensor replacement?

[Tem]

About the clock, IIRC, it doesn't even have 0:00...

Doesn't it go from 12:59 -> 1:00

[kanujunkie]

About the clock, IIRC, it doesn't even have 0:00...

Doesn't it go from 12:59 -> 1:00

yeah it does do that, but it will go from 11:59 -> 0:00

[Tem]

Doesn't it go from 12:59 -> 1:00

yeah it does do that, but it will go from 11:59 -> 0:00

Which one?  s:lol: :lol: s:lol:

If it goes from 11:59 -> 0:00, how could it ever reach 12:59 to go to 1:00?  s:? :? s:?

[aaronjb]

Doesn't it go from 12:59 -> 1:00

yeah it does do that, but it will go from 11:59 -> 0:00

Which one?  s:lol: :lol: s:lol:

If it goes from 11:59 -> 0:00, how could it ever reach 12:59 to go to 1:00?  s:? :? s:?

Ssshh, I think it's his age catching up with him  s;) s;)

[philster_d]

I think we hay have got the crackers mixed up.

Subsequently, Aaron has gon off with Stu's marbles   s:D s:D

[Anonymous]

 s:evil: :evil: s:evil:  

This is really   s:!: :!: s:!:   me off.  Yesterday a friend popped over with a multimeter to check all the wiring from the sensor to see if I had in fact wired it correctly and the wires were giving a signal.  After testing all the wires we re-crimped the connection joins a little tighter which made the signal wire report a low current (something it was not doing before).  my mate said the current was lower than what he was expecting (I'm no good at electrics so don't ask what it was reading) and thought maybe it would increase as the engine warmed up.  Either that or the new sensor I fitted was shagged.  

So i disconnected the battery, left it off for over 4 hours. Then reconnected, and drove home. By the time I got home the temperature guage was up to normal, the car was idling fine and I was happy that I had completed one drive cycle (going on the assumption that the CEL will only appear after it detects errors on 3 seperate cycles of the engine warming up and cooling down).

I took the car out again for it's 2nd drive since disconnecting the battery and the light came on almost immediately!   s:cry: :cry: s:cry:  

This must mean either one of two things:

1.  The idea that the ECU needs to detect a fault 3 times is rubbish and it's displaying the CEL as soon as it sniffs something is wrong

2.  The ECU needs it's fault log cleared.  The sensor is working perfectly but the ECU still has a record of their being a fault at some point and this needs to be cleared.

It doesn't make sense that the CEL would come back on at the start of the second journey. Can anyone confirm which is the most likely thing happening here, or is there another scenario I haven't thought of?

Thanks

Yorkie

PS: regarding the clock discussion above, surely 11:59 > 0:00 is over midnight and 12:59 > 1:00 happends during midday

[edward.carter]

I am 99% sure last time i reset mine it did go to 0:00

[Tem]

PS: regarding the clock discussion above, surely 11:59 > 0:00 is over midnight and 12:59 > 1:00 happends during midday

I'm sure mine's a 12-hour clock and it cannot tell the difference between midnight and noon. Maybe you have a different clock in UK, if it does  s:? :? s:?

[edward.carter]

PS: regarding the clock discussion above, surely 11:59 > 0:00 is over midnight and 12:59 > 1:00 happends during midday

I'm sure mine's a 12-hour clock and it cannot tell the difference between midnight and noon. Maybe you have a different clock in UK, if it does  s:? :? s:?

pretty sure its a 12 hour clock here too. this threads just confusing me   s:? :? s:?    im off to look at some pictures or something   s:) s:)

[spit]

I took the car out again for it's 2nd drive since disconnecting the battery and the light came on almost immediately!   s:cry: :cry: s:cry:  

This must mean either one of two things:

1.  The idea that the ECU needs to detect a fault 3 times is rubbish and it's displaying the CEL as soon as it sniffs something is wrong

2.  The ECU needs it's fault log cleared.  The sensor is working perfectly but the ECU still has a record of their being a fault at some point and this needs to be cleared.

It doesn't make sense that the CEL would come back on at the start of the second journey. Can anyone confirm which is the most likely thing happening here, or is there another scenario I haven't thought of?

Thanks

Yorkie

PS: regarding the clock discussion above, surely 11:59 > 0:00 is over midnight and 12:59 > 1:00 happends during midday

Sorry you're having such probs Yorkie, and its difficult - if not impossible - for any of us to diagnose without hands-on, but we can perhaps offer a few pointers from our own experience and what we've read elsewhere.

The O2 sensor sends a specific voltage to the ECU, switching between 0 volts and (approx) 1 volt dependent on which side of "OK" it is reading. The ECU's trick is to make adjustments to try & hold the voltage somewhere at the switching point (0.48v IIRC). Perhaps someone with a 3rd O2 can explain further what its purpose and relation to the ECU trimming is??

You can check out this voltage across the signal and signal ground with a meter set to "volts DC" without upsetting anything - at least I have done many times. Hopefully you'll register a fluttering voltage somewhere >0 and <1volt

Apparently you shouldn't measure ohms across these wires as it can damage the sensor. As for current, I've no idea!

The two remaining wires are heater circuit and should read a resistance of approx 15 ohms. If they don't, the ECU will throw a CEL on the second start-up.

If these things - and your wiring - are checking out OK, then perhaps a return to what the CEL is telling you might be the diagnosis of the problem?

As for the clock thing .....   s:shock: :shock: s:shock:

[Anonymous]

If I was to do the work on the O2 sensor myself would the engine management light go off automatically or would I need a reader to delete the fault code and turn the light off?

Cheers!

Chris   s:) s:)

[spit]

O2 heater circuits seem to be popping up all over the place at the moment  s:shock: :shock: s:shock:

If I was to do the work on the O2 sensor myself would the engine management light go off automatically or would I need a reader to delete the fault code and turn the light off?

Provided the ECU is seeing a heater circuit with a resistance of circa 15 ohms, the light will go off without needing a reader.

If you're happy with wiring, get a cheaper clone sensor and tap it in. A 15ohm resistor across the sensors' black wires will clear the code as a temporary fix if you're not ready to replace the sensor yet (but get a high-power ceramic-coated resistor and keep an eye on it...... it'll get hot!).

Ste

[rmowbray]

(but get a high-power ceramic-coated resistor and keep an eye on it...... it'll get hot!).

It sure will!  s:wink: :wink: s:wink:   If the battery is a nominal 13.8V then the rating should be:

13.8^2 / 15 = 12.7W

How about one of these then:

 m http://rswww.com/cgi-bin/bv/rswww/subRa ... cheID=ukie m

Stock no: 160-455

 £1.35 in single multiples

[spit]

Thanks for the link Richard & you have PM.

Its weird, cos there seems to be no logic to the heat thing  s:shock: :shock: s:shock:  I used a £0.10 Maplin resistor connected in a terminal block for three months with no problems. Alberto (Spynish) and I both had 3W ceramic coateds in there for a while, and he had probs but I didn't.

I've now upped to 10W/20W peak ceramics (I worked to 12V feed from ECU rather than the battery's nominal 13.8V) & the terminal blocks have melted   s:( s:(  so now they're soldered in directly with heatshrink insulation and seem to be OK - but I'd like a tidier and more permanent solution.

Alberto has reverted back to using his NB heater circuit (see his thread) but I'm on wideband analog feed to ECU now and my stock's circuits are fried  s:cry: :cry: s:cry:

Aside - and just a bit o' fun! - are there any alternatives to a resistor? eg a motor or bulb that constantly provides the appropriate resistance within +/- 15% or so? I'm afraid my knowledge of these things is down there with my understanding of the offside rule  s:shock: :shock: s:shock:  so it might be a dumb question.....

[Anonymous]

UPDATE:

I managed to get the troublesome sensor out of the car again and tested all the wires.

I wasn't getting any resistance across the two heater wires, nor were they making a circuit. I was reading a voltage on the signal wire as expected but nothing on the heater wires. so concluded the heater wires were knackered on my new (!) sensor I had just ordered and taken hours to install.

WORD OF ADVICE: test the wires on the new 02 sensors bofore you replace it.

as there was no point putting a non working sensor back in the exhaust I simply put my original sensor (the one which caused the warning light to come on in the first place) back in, simply to plug up the hole in the cat.

I started the car and to my surprise no warning light! Then I thought, why not keep it like this. If the job of the 02 sensor is simply for EU emmissions regulations then why do I need it [working]? My car is now effectively just like the jap car's which don't have the third sensor (am I right in saying this?).  since the ECU doesn't know there is a sensor there, it doesn't think there's a problem!

Is it safe to leave it like this? if anything, the car felt a little more responsive and nippy - but that might just be me

Yorkie

[spit]

Have you tried running the car again? You get one free run after ECU reset .... the heater circuit CEL appears at second start-up.

Strange that your new sensor's heater circuit appears to be defunct. Hope you can get a refund.

AFAIK its safe to run the car without an O2 heater circuit, but unlikely that you'll avoid a CEL.

[Anonymous]

Spit, you're spot on!

Just got back from a week's holiday. Took the car out a few times over the weekend, not driven it since my last post.  Indeed, the CEL came back on.

I don't think I can get a refund from the place I bought the sensor as the packaging said no refunds once the sensor has been fitted. So should I:

1. Order a new sensor from the same place, test it, if it looks good then crimp it onto the existing wiring and pop it in (cost = £37.50 + fitting time)

2. Source a complete cable from a smashed up roadster from a breaker (cost = dunno yet + fitting time)

3. Order a straight through pipe without a cat (cost = err, anyone care to estimate?) Presumably this would also involve doing some work with the ECU?

Your thoughts please.

Mike

Mike.

[spit]

I don't think I can get a refund from the place I bought the sensor as the packaging said no refunds once the sensor has been fitted.

B*gger  s:? :? s:?

So should I:
1. Order a new sensor from the same place, test it, if it looks good then crimp it onto the existing wiring and pop it in (cost = £37.50 + fitting time)
2. Source a complete cable from a smashed up roadster from a breaker (cost = dunno yet + fitting time)
3. Order a straight through pipe without a cat (cost = err, anyone care to estimate?) Presumably this would also involve doing some work with the ECU?

Mike, I suppose you might have another option of kicking up a stink about their "no refunds" policy as you were clearly sold a duffer (Sale of Goods Act and all that?)

Your choice over option 1 or 2 really, but given your experience you might want to check the heater circuit before committing either way  s:wink: :wink: s:wink:

If this is the third O2 sensor (post-cat) that we're talking about, I believe there is a "fix" to do away with it completely and avoid the CEL - perhaps someone who has a 3rd O2 can post details cos I've never fully understood the reason for having it in the first place  s:oops: :oops: s:oops:

Are you de-pre-catted? If you are, don't forget to consider the impact on the MOT emissions of running straight-through (or the impact on you of refitting the Cat every year!). In any case, this won't stop the ECU from expecting to see a signal from the 3rd O2 - so looks like you're back to the "fix" method anyway.

I used the "10W 15ohm ceramic-coated resistor across the black wires" trick on my manifold O2 sensor when its heater circuit went - that clears the CEL, but the resistor gets f- hot ! Still, its a possible option 4 for you, and something you can try out on the duffer to clear your CEL until you decide proper.

Best o' luck
Ste

[Anonymous]

An update to this problem:

I've been driving around for months with the same broken 02 sensor still in the exhaust. After my last attempts to fix it I was annoyed at the problems I had just left it until now. I want to fix this once and for all so went back to Gendan and bought ANOTHER sensor, same as the last.

I took it round a friends house who is a proper mechanic (different mate from before). he soldered the wires together, heatwrapped them, installed the sensor and we reset the ECU. 3 journeys later the b@stard light is back on.

Which means either:

- I've been sent two duff sensors from Gendan (unlikely but possible)
- Nothing is wrong with the sensors and I have been replacing working parts - the fault is elsewhere
- which means Toyota told me the incorrect fault code when I asked them to diagnose it (they told me P0141)

Anyway, I'm so annoyed at this I'm going to bung a resister in there becuase I've spent near £100 on two 02 sensors and an 02 sensor socket without fixing the problem and will have to spend another £200+ on getting Toyota to fix it - because clearly I'm not doing it right!

So, what's the procedure for using a resistor?

Will a "10W 15ohm ceramic-coated resistor across the black wires" do the trick? can I mount it anywhere along the wires (ie the colder end of the wires as opposed to right next to the exhaust)?

Advice very welcome.

Mike.

[spit]

Hmmm. On the face of it, with a P0141 code, yes, a resistance across the blacks should fool the ECU. The last 3rd O2 fix that I did, I cut the wires close to the knackered sensor, pulled them out of the sleeving and gave them a heatshrink of their own so that the resistor could be chassis mounted clear of all hot and vulnerable stuff.

BUT

the history of what you've been through suggests that the O2 heater malfunction might be a red herring:

1) Maybe you were given the wrong code
2) Maybe there was more than one code that you weren't told about
3) Maybe the wiring integrity between sensor and ECU has been compromised
4) Maybe a different code has sprung up since the first fix
5) Other !

Before hacking and/or spending more money, I'd be inclined to find a member nearby with a reader and start again from there.

2 damaged sensors on the trot seems very unlikely, unless you've accidentally cabbaged them both by trying to read their resistance across the signal and signal ground wires - they don't like that!

Sorry its not a clear and definitive answer, but with a little more patience you should be able to get it nailed and then you'll wonder what all the fuss was about  s:wink: :wink: s:wink:  Car runs fine I take it?

[Anonymous]

Have the same problem after changing the cat sensor!  Sometime CEL is ON and OFF after 2 or 3 days!  Checking with obd2 and digimoto show the sensor working!  We need a resistor or O2 simulator.  s:) s:)

[Anonymous]

The saga continues...

Just returned from Toyoto to have a fresh reading. the service guy said the computer will return present fault codes and any historic fault codes. He went on to say that codes will be moved to 'historic' after 20 full-cycles of starting up and colling down without reading the problem.

So, the diagnosis was:

P0141 (bank 1 sensor 2)
P0135 (bank 1 sensor 1)

So I have two problems. And the one I've been trying to fix all this time isn't fixed. As you may read in my previous posts, I've bought two Denso 4-wire universal 02 sensors and neither have fixed the problem. Has anyone used one and can confirm it fixed their problem?

I'm resigned to buying official Toyota parts, is there somewhere I can buy them online and saving a few bob from the dealer prices?

Is it correct about the 20 start-stop historic fault code thing mentioned above?

Mike

[Anonymous]

Gendan do the actual plug and play sensor, which is what I have ordered, it is exactly the same part no. that Toyota quote, I think its about £30 cheaper than MR T quoted; however I ordered it over a week ago, they dont have it in stock, and Im still waiting.

http://www.gendan.co.uk/product_LB1563.html#product_information

Hope this helps.

[Anonymous]

hmm, two of those should do it. Thanks

I did notice when I removed the bust Toyota 02 sensor that the metal surround covering the tip of the sensor was "bullet-hole'd" and the replacement Denso sensor I ordered were solid tipped, as in this picture:  m http://www.gendan.co.uk/product_O24WIRE.html m

I guess I'll give this a go and see what happens. I was quoted £360 which included all parts, labour and VAT so I should save myself well over £100 doing it DIY stylee. Let's hope it bloody well fixes the problem!

Mike.

[Anonymous]

hang on...

I've noticed the cable on this site says it's 350mm. I'm no mathmatician but I make that 35cm which isn't going to be long enough to get from the back of the light cluster to the exhaust. The existing cabling from the exhaust sensor is at least 1m in length.

Having just checked with Toyota about their part numbers for the manifold sensor (89465-17180), the part listed on the Gendan website does look correct. So that's the manifold sensor covered.

Now I just need one for the exhaust sensor (bank 1, sensor 2), part no 89465-17201.

Anyone?