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Toyota Corrola 1.6 2003 - MIL on, code 420 cat threshold efficiency exceeded #

Posted by Simon Dean on January 4, 2010, 11:17 am

Year of Manufacture *: 2003
Engine Code or CC *: 1600
( Optional ) Scanner Used: Auto diagnos

Morning
Mil Light on code 420 cat threshold eff% exceeded.

New type aprroved cat on car with 2 good adl new oxy sensors
emissions mot pass

over time mil comes on with above code
smoke test inlet and exahust/no pressure drop or apparent leaks.

fuel trim stft 8% and long ltft -0.8% ??

firstly do i need to reset eobd protocol and can someone advise correct procedure for this please including roadtesting distance
Secondly i am thinking air mass reading incorrectly over time??

just going to inspect air mass sensor for dirt/debris
Any thoughts please

Thanks
Simon

Re: toyota corrola

Posted by roy ritchie <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5115' width='330' height='300' border=0 style='border:none;'> on January 4, 2010, 11:59 am, in reply to "toyota corrola"

(New type aprroved cat)Who says the new aprroved cats are perfect,Is the front sensor switching ok?If so whats the rear sensor doing?If you have a scope watch both sensors,The cats the number one suspect.

Re: toyota corrola

Posted by simon dean <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5221' width='330' height='300' border=0 style='border:none;'> on January 4, 2010, 2:08 pm, in reply to "Re: toyota corrola"
Simon Dean

Thanks Roy
Busy at mo,no i havent scoped sensors yet but i do have a perfect gas test at idle and cruise.

I am currently wanting to understand the eobd reset and readiness tests/drive cylces to ensure the system is correctly set before i put vehicle back on road.
Chocker today so will see what i can find first and report back.

thanks
simon

Re: toyota corrola

perfect gas test at idle only means the cat is good for a gas test not that ecu is happy with cat,The readings from second lambda should give you a better idea.

Re: toyota corrola

Posted by Dave Harney <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2603' width='330' height='300' border=0 style='border:none;'> on January 4, 2010, 8:43 pm, in reply to "Re: toyota corrola"

Hi Simon,
Hopefully there will be some useful info here for you......

http://members.iatn.net/resources/toyota/rmdp/rmdp_01.html

Regards
Dave
Looks like you will need to register to view this info !!

You can trim a sheeps wool many times, but you can only fleece it once !

Re: toyota corrola

Posted by Tony Sefton <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5581' width='330' height='300' border=0 style='border:none;'> on January 4, 2010, 11:28 pm, in reply to "Re: toyota corrola"
Tony Sefton

I have Seen More Cars in the past few months than ever before with P0420 Logged, most of these cars have recently had what were supposed to be TYPE APPROVED Cats fitted.

I would think that the way things seem to be going, that TYPE APPROVED Does not Mean Quality Assured, OE spec etc. ??

Who Type approves these things. ? I would think that the only True company that could
Correctly say that these Cats were up to Spec would be The Vehicle manufacturer. ? i,e in this Case Toyota. ?

Otherwise the People Approving them ought to have some responsibility in finding out why so many are failing. ?

Tony.

Re: toyota corrola

Posted by Simon Dean <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5221' width='330' height='300' border=0 style='border:none;'> on January 5, 2010, 11:04 pm, in reply to "Re: toyota corrola"
Simon Dean

Thanks dave will register and take a look.

Fault was present on Toyota original cat and Would take a month then same code.
Customer had a TA cat and oxy,s fitted same re occurrence 1 month later,

So cat quality has a question mark over it yes.
I have disconnected battery and powered down to allow eobd reset.

Possible intermittent fueling fault?
next step...air mass and lambda signal tests with scope to establish correct fueling operation.
iatn look up also.
will post when done.

thanks Simon

Re: toyota corrola

Posted by ian slattery <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1196' width='330' height='300' border=0 style='border:none;'> on January 6, 2010, 9:03 pm, in reply to "Re: toyota corrola"

I heard that on some toyotas there is a ecu reflash on this code. I was asked to find the ecu for a big tyre company who had fitted a cat. You need the ecu number. At the time i thought they were looking for a get out claus Don't know the outcome or where to find the information to confirm this.
http://repairpal.com/OBD-Code-P0420-Toyota

Re: toyota corrola

Posted by Keith Simpson <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1240' width='330' height='300' border=0 style='border:none;'> on January 6, 2010, 11:40 pm, in reply to "Re: toyota corrola"

The point of the Software update is to widen the threshold so an aftermarket cat can be fitted. This update dosn't always work as it depends on the quality of the cat fitted at the time. The problem you are having is because the cat fitted is not fit for purpose, and a genuine cat will cure the problem.

Keith

Re: Toyota Corrola 1.6 2003 - MIL on, code 420 cat threshold efficiency exceeded #

Posted by Simon Dean <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5221' width='330' height='300' border=0 style='border:none;'> on January 9, 2010, 2:39 pm, in reply to "Toyota Corrola 1.6 2003 - MIL on, code 420 cat threshold efficiency exceeded #"
Simon Dean

Hi All
OK So P0420 Catalyst threshold exceeded bank 1

I will be tackling this soon and am going this way!
Software..if there is an upgrade which moves the parameters of the monitoring function then i will do this first to see what happens.
(the original OE cat passed emissions every time,however a gas analysis is not as accurate as a scope test across both sensors).

So i am presuming the rear O2 sensor is 'seeing' an oxygen content over time.this will according to data i have read start to happen when the rear O2 hits 625mv I.E oxygen seen coming out of cat showing incorrect conversion the rear O2 signal will react with a lower MV reading(presuming a correctly fueling vehicle and a correct cat conversion would have the rear O2 sitting at 800mv all day long).

So an air mass to front oxygen sensor test for responce with a scope will tell me the integrity of the injections systems fueling.

So if thats right i will do the following.

I will scope test the front sensor signal and rear sensor signal together and light the cat at fast idle and watch the responce of the rear O2 if a cat fault i will see the sensor lower to 625mv or lower.

wish me luck LOL.
ps..i have already carried out a smoke pro test to inlet and exhaust and all ok.

Let u know soon
Simon

Re: Toyota Corrola 1.6 2003 - MIL on, code 420 cat threshold efficiency exceeded #

Posted by Steve Harrison <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1363' width='330' height='300' border=0 style='border:none;'> on January 10, 2010, 6:24 pm, in reply to "Re: Toyota Corrola 1.6 2003 - MIL on, code 420 cat threshold efficiency exceeded #"
Stephen Harrison

Tony

The thing I find quite amusing about the type approval on cats is that even if the cat is a good one there is nothing to stop a £15 "universal" lambda sensor being fitted

Steve

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