Hard to believe but after all my previous troubles now covered over 1000 miles trouble free with new main cat, and now EML light on again. Same reading of cat inefficiency. Incredible !!
Just wondering if it is possible to bypass the two pre cat sensors to start with to isolate them and I understand there is a wiring mod to achieve this but does anyone know of who can supply modified wiring to achieve this.
If not it is back to the sensors once again and reading previous articles it seems that most are only fitting denzo items. Again does anyone have a view on these and where I can get the three items (2 pre cats and 1 main) as probably a good place to start now that the cat has been replaced and problem far less frequent than before.
Best Wishes
Chris
Have you read the code just to confirm o2 sensors.
to source.
sparkplugs.co.uk
amazon
i fitted denso. Fit n forget.
Quote from: "Ardent"Have you read the code just to confirm o2 sensors.
to source.
sparkplugs.co.uk
amazon
i fitted denso. Fit n forget.
As above.
Worth the money just to save hassles.
Had a reply from "sparkplugs" but they require part numbers which I don't have.
Code says "cat efficiency below threshold bank 1" but sensors and cat now replaced so wonder if replacement sensor is up to scratch
That code is generated by the third O2 sensor which is in the pipe after the main catalyst ... not the ones in the manifold.
So could be the cat then? Was it a cheap aftermarket? Has the car passed an MoT since fitting it?
Emissions have been checked and reading perfect and car goes well too. Yes it was aftermarket cat has anyone out there got a genuine Toyota one that I can purchase to try?
Quote from: "Wabbitkilla"That code is generated by the third O2 sensor which is in the pipe after the main catalyst ... not the ones in the manifold.
Thanks I thought the Bank 1 reading was associated with the pre cat sensors?
Quote from: "chris goldson"Quote from: "Wabbitkilla"That code is generated by the third O2 sensor which is in the pipe after the main catalyst ... not the ones in the manifold.
Thanks I thought the Bank 1 reading was associated with the pre cat sensors?
It's a generic code, hence the sensors....
Bank 1 Sensor 1 = Right hand side of manifold ...Part code DOX-0204
Bank 2 Sensor 1 = Left hand side of manifold ....Part code DOX-0204
Bank 1 Sensor 2 = Post cat sensor ..................Part code DOX-0206
So if you're getting cat reading under efficiency and emmissions test show it's ok then B1S2 is running out of life, and they do fail over time.
Many thanks for this. Is the B152 the post cat one as this was replaced but don't think it was with a denzo part
Quote from: "chris goldson"Many thanks for this. Is the B152 the post cat one as this was replaced but don't think it was with a denzo part
Bank 1 Sensor 2 = Post cat sensor ..................Part code DOX-0206
Quote from: "chris goldson"Many thanks for this. Is the B152 the post cat one as this was replaced but don't think it was with a denzo part
He said B1S2 not B152. i.e. the post cat sensor, bank 1 sensor 2.
This failed on my car too and caused the EML to come on. Fitted a Denso from sparkplugs.co.uk and all has been well since. It's an easy enough job if you remember to buy an oxygen sensor spanner.
Problem is "sparkplugs" are saying I have to "cross reference from the OE part currently installed or as advised by a Toyota main dealer"
Quote from: "chris goldson"Problem is "sparkplugs" are saying I have to "cross reference from the OE part currently installed or as advised by a Toyota main dealer"
As someone above said - DOX-0206 is the Denso part number.
(FWIW, DOX-0204 is the other two)
http://www.sparkplugs.co.uk/denso-oxygen-sensor-dox-0206
Many thanks.
Still searching for a genuine Toyota Cat as might change that as well at same time
Quote from: "chris goldson"Many thanks.
Still searching for a genuine Toyota Cat as might change that as well at same time
That might be expensive! If your emissions are ok, you might be better fitting one of these (this one is just an example, make sure you get one that fits!)... m http://www.ebay.co.uk/itm/UNIVERSAL-EXH ... SwkZhWTcbz (http://www.ebay.co.uk/itm/UNIVERSAL-EXHAUST-MANIFOLD-DECAT-DE-CAT-O2-LAMBDA-FOOLER-TRICKER-SENSOR-CEL-FIX-/151889088742?hash=item235d4b90e6:g:TGQAAOSwkZhWTcbz) m
If you have an obd2 reader that can give real-time data then you should be able to tell if the post cat lambda sensor is working by assessing the variability of the output data. Maybe the problem is that sensor?
If the emissions were tested and good, the cat is working.
Just spotted another cat on ebay which says Toyota 12209 Sango, does anyone know if this is a genuine Toyota cat and if it will fit my 2006 MR2. Anything worth a try to put the light out !!
Quote from: "chris goldson"Just spotted another cat on ebay which says Toyota 12209 Sango, does anyone know if this is a genuine Toyota cat and if it will fit my 2006 MR2. Anything worth a try to put the light out !!
Contact the seller and ask for the part number?
However, if the emissions are OK then it doesn't seem worth the expense and cost of replacing the cat. Either it is a poor post-cat lambda sensor OR the current cat is functional but inefficient, in which case an aporopriate sensor spacer may be a more cost-effective fix.
What code are you actually getting?
Might be worth having a read of the Lambda / O2 sensor thread.
The heating circuit is well known to be a bit duff. Perhaps putting a resistor in might fix?
Quote from: "Jon_G"Quote from: "chris goldson"Just spotted another cat on ebay which says Toyota 12209 Sango, does anyone know if this is a genuine Toyota cat and if it will fit my 2006 MR2. Anything worth a try to put the light out !!
Contact the seller and ask for the part number?
However, if the emissions are OK then it doesn't seem worth the expense and cost of replacing the cat. Either it is a poor post-cat lambda sensor OR the current cat is functional but inefficient, in which case an aporopriate sensor spacer may be a more cost-effective fix.
What code are you actually getting?
Not sure about the code but will ask. I have not heard of a spacer how would I do this?
Thanks for your help
Best Wishes
Chris
Well worth getting a code reader. Not expensive and will pay for itself first time you use it.
Quote from: "chris goldson"Quote from: "Jon_G"Quote from: "chris goldson"Just spotted another cat on ebay which says Toyota 12209 Sango, does anyone know if this is a genuine Toyota cat and if it will fit my 2006 MR2. Anything worth a try to put the light out !!
Contact the seller and ask for the part number?
However, if the emissions are OK then it doesn't seem worth the expense and cost of replacing the cat. Either it is a poor post-cat lambda sensor OR the current cat is functional but inefficient, in which case an aporopriate sensor spacer may be a more cost-effective fix.
What code are you actually getting?
Not sure about the code but will ask. I have not heard of a spacer how would I do this?
I already supplied an eBay link in an earlier post (you'll need to find one that fits the MR2!). It's an extender that goes between the sensor and the exhaust to reduce sensitivity and is often needed when de-catting to create a pre-cat/post-cat differential reading.
Quote from: "Ardent"Well worth getting a code reader. Not expensive and will pay for itself first time you use it.
Definitely!
Thanks. Yes had a look at the extenders they seem to be 18mm thread which hopefully is the same on the cat. Is there room for a straight one or would I need an angled one to fit?
I don't suppose there is a lot of point getting an expensive code reader
Quote from: "chris goldson"Thanks. Yes had a look at the extenders they seem to be 18mm thread which hopefully is the same on the cat. Is there room for a straight one or would I need an angled one to fit?
I don't suppose there is a lot of point getting an expensive code reader
An £8 one does the trick for me s:mrgreen: :mrgreen: s:mrgreen: (Although you need to snip two of the pins off, because it makes the ABS light go nuts and my airbag light is half on)
Quote from: "chris goldson"I don't suppose there is a lot of point getting an expensive code reader
Non at all.
Quote from: "Carolyn"If the emissions were tested and good, the cat is working.
If the primary/manifold/precat cat is still present (and functional) then the emission readings may still be pretty good, even if the main cat was operating below standard?
It's quite confusing the different views on the pre-cats and other issues.
I know members have said that doing the mods on the pre cats should not lead to EML problems but when I look on the sites advertising the main cat extenders they say they are a must in keeping the EML light off if the pre cats are missing or have been modified. If keep having problems might try one of these on the main cat to see if it does the trick.
Quote from: "chris goldson"It's quite confusing the different views on the pre-cats and other issues.
I know members have said that doing the mods on the pre cats should not lead to EML problems but when I look on the sites advertising the main cat extenders they say they are a must in keeping the EML light off if the pre cats are missing or have been modified. If keep having problems might try one of these on the main cat to see if it does the trick.
Do you still have your precats fitted? I have, but many do remove them... I don't believe that removing them should cause an EML problem UNLESS your main cat is defective.
I'm still not convinced about what your problem is. Confirming what the fault code is would be useful (as would knowing if you still have the precats fitted).
At least fitting that spacer is one of the cheaper options.
I have two cars. One with a Toyosport manifold and aftermarket cat and one with a de-catted stock manifold and stock cat. Both have no EML light. Both pass emsissions testing. Neither uses a spacer/extension on any sensor. It looks most likely that it is a sensor problem.
I thought the only reason you fitted a spacer was if you had a sports cat fitted.
Pre cats do very little once main cat is up to temp.
I have no pre cats and a 200 CEL sports cat and have no issues with passing mot or eml.
Quote from: "Jon_G"Quote from: "chris goldson"Many thanks.
Still searching for a genuine Toyota Cat as might change that as well at same time
That might be expensive! If your emissions are ok, you might be better fitting one of these (this one is just an example, make sure you get one that fits!)... m http://www.ebay.co.uk/itm/UNIVERSAL-EXH ... SwkZhWTcbz (http://www.ebay.co.uk/itm/UNIVERSAL-EXHAUST-MANIFOLD-DECAT-DE-CAT-O2-LAMBDA-FOOLER-TRICKER-SENSOR-CEL-FIX-/151889088742?hash=item235d4b90e6:g:TGQAAOSwkZhWTcbz) m
If you have an obd2 reader that can give real-time data then you should be able to tell if the post cat lambda sensor is working by assessing the variability of the output data. Maybe the problem is that sensor?
Hi Jon
Most of these look to be 50mm long, I have not had a look to see where the sensor fits but wonder if there is enough room to get one of these in although there are angled ones as well. Do you know if there is room to fit one pleasef
No idea, sorry. Never had to fit one!
Quote from: "Jon_G"Quote from: "chris goldson"Just spotted another cat on ebay which says Toyota 12209 Sango, does anyone know if this is a genuine Toyota cat and if it will fit my 2006 MR2. Anything worth a try to put the light out !!
Contact the seller and ask for the part number?
However, if the emissions are OK then it doesn't seem worth the expense and cost of replacing the cat. Either it is a poor post-cat lambda sensor OR the current cat is functional but inefficient, in which case an aporopriate sensor spacer may be a more cost-effective fix.
What code are you actually getting?
Jon
Just picked the car up again. All three sensors have been changed now to Denzo's and cat replaced during previous visit. The fault code which has been consistent throughout was P0420 cat below threshold bank1. Obviously not know for some time if this has now been resolved.
Best Wishes
Chris
Fingers crossed that this problem has now gone. I guess that'll mean it was the lower sensor.
Hope it is sorted now.
Was the exhaust ssytem checked for gas leakage as this can also throw the P0420 code.
Yes they had to do a few welds around the pre cats, probably could do with a new/another unit at some stage, but still going for the spacer if the dreadedd EML comes on again.
Quote from: "chris goldson"Yes they had to do a few welds around the pre cats,
Could you elaborate on that.
Hi yes they had to do some welds around the tops of what they called the jam pots where there where some hairline cracks
if you need a replacement. Bound to be one floating around on here as people swap them out.
Not heard of one needing welding before.
Welding of the stock cast manifold is news to me.
Its around where the four pipes from the manifold go into the two pre cats.
Don't know if there is a wanted section or parts for sale on here to find a replacement which would be ideal?
l viewforum.php?f=63 (http://mr2roc.org/phpBB3/viewforum.php?f=63) l
Quote from: "Ardent"Hope it is sorted now.
Was the exhaust ssytem checked for gas leakage as this can also throw the P0420 code.
Guess what EML light on again - beyond belief !!
All three sensors changed and new cat but still same problem and same code. Now fitted spacer to see if that does the trick but patience now more than a little thin.
My money is still on an exhaust leak. Hope I'm wrong and the spacer does the trick.
Do you have all the heat-shields on around the manifold? I ask this as there is a simple way if tracking a leak down - but you need access. A piece of coat-hanger wire, with some tissue taped to one end. Pass it around all the places where it might leak, welds and joints. You'll see it flutter when you get close.
I'm watching this with interest as I have exactly the same issue.
So you found a spacer... was it a 18mm thread like the eBay examples?
If this doesn't fix it, then it can sometimes be necessary to stuff wire wool into the spacer to further reduce sensor sensitivity.
Good luck with it, hope it'll stay OK.
Thanks Jon much appreciated. Yes it is 18mm thread
I had P0420 and my emission results were pretty bad. After a bit of internet research, I took the cat section of the exhaust off and flushed it with hot citric acid solution for 6 hours. Unfortunately, I couldn't get the sensor out and bent it whilst trying. I also noticed that there was probably still a leak where the pipes joined the flange for the manifold (I'd tried fixing this whilst it was on the car and couldn't feel a leak when it was running). I put fire cement all the way around the joint (I don't know if it's cat-safe but I had it in the garage so thought I'd use it).
I don't know whether it was the flushing or there was a leak but the p0420 hasn't come back and my fuel economy has gone up. Unfortunately I've created a P0141 heater circuit code from that sensor but research on here suggests the sensor is working and that there's a resistor fix for the heater circuit.
Quote from: "Jon_G"So you found a spacer... was it a 18mm thread like the eBay examples?
If this doesn't fix it, then it can sometimes be necessary to stuff wire wool into the spacer to further reduce sensor sensitivity.
Good luck with it, hope it'll stay OK.
Hi Jon
Fitted stainless spacer three weeks ago and trying not to speak too soon but light has not come back on after a lot of journeys and quite a few miles. Don't exactly know why fitting this should make a difference but hopefully if the light remains off then it has done its job. Goes just as well too so no problems there.
Also flushed it through with both injector cleaner and fuel line cleaner.
Thanks for your help.
Best Wishes
Chris
Quote from: "chris goldson"Quote from: "Jon_G"So you found a spacer... was it a 18mm thread like the eBay examples?
If this doesn't fix it, then it can sometimes be necessary to stuff wire wool into the spacer to further reduce sensor sensitivity.
Good luck with it, hope it'll stay OK.
Hi Jon
Fitted stainless spacer three weeks ago and trying not to speak too soon but light has not come back on after a lot of journeys and quite a few miles. Don't exactly know why fitting this should make a difference but hopefully if the light remains off then it has done its job. Goes just as well too so no problems there.
Also flushed it through with both injector cleaner and fuel line cleaner.
Thanks for your help.
Best Wishes
Chris
I'm glad it's OK now but, as you say, it's only been 3 weeks...
I'm guessing that the new main cat is ineffective, hence the need to 'fool' the end lambda sensor. But in that case the pre-cats must be working sufficiently to help with keeping the emissions low enough for the MoT.
Thanks Jon yes time will tell !!
The pre cats have had their internals removed before I purchased the car so guess they can't be helping.
Best Wishes
Chris
Well that completely undermines my theory then!
Hope it stays OK...
Quote from: "Jon_G"Well that completely undermines my theory then!
Hope it stays OK...
Light still off and just put in my second tank full of petrol. Never gone this far without it coming on !!
Fingers crossed still !!!
I know that this has been some time, how's it going? Is the EML back on or was the fix successful. I've exactly the same problem.
What especially interests me is that this started after you had a new main cat fitted? If so, who did you use for the replaement cat? Other research seems to suggest some dodgy main cats about being supplied by some of the big exhaust companies. I'd be interested in the details, thanks