Technical P0420 - Catalyser 1 fatal?

[KRaikkonenNo1]

Hi, I've been getting this code every couple of months or so, but it hadn't brought the eml on and multiecuscan said it wasn't 'fatal', therefore I kept clearing the code and assumed was ok for now. BUT earlier this morning I seen the eml come on, used MES and I've been given this code where it says this time 'fatal'.

Any help with this, I haven't cleared it yet as am gonna wait for advice from you guys first. Maybe lambda sensor, cat?

Any help as always appreciated, thanks.

 

[oldhammer]

Try cleaning cat. perhaps?

use something like this.

http://www.ebay.co.uk/itm/CATACLEAN...arts_Vehicles_CarParts_SM&hash=item2a2be2cf34

 

[Ziggy122]

Since your've got MES working

Go to the actutor sensors area - get the Pre and post lambda sensors voltage output and stick them on the graph and watch for as long as possible

the Pre cat - should peak and trough
The post cat should be sitting roughly middle and fairly consistant, it'll be changing but not dramatically

Ziggy

 

[bonkersbassist]

Try cleaning cat. perhaps?

use something like this.

http://www.ebay.co.uk/itm/CATACLEAN...arts_Vehicles_CarParts_SM&hash=item2a2be2cf34

or this:

 

[KRaikkonenNo1]

Try cleaning cat. perhaps?

use something like this.

http://www.ebay.co.uk/itm/CATACLEAN...arts_Vehicles_CarParts_SM&hash=item2a2be2cf34

Used this before, very good product, would recommend! Might pick some up again! :thumbup:

 

[KRaikkonenNo1]

Since your've got MES working

Go to the actutor sensors area - get the Pre and post lambda sensors voltage output and stick them on the graph and watch for as long as possible

the Pre cat - should peak and trough
The post cat should be sitting roughly middle and fairly consistant, it'll be changing but not dramatically

Ziggy

These are the results I just quickly got, do they seem normal?

Also is it normal when performing this for my cars revs to sit at 1500 then continue to dip and rise to 2000, very drastic revving?

Thanks.

 

[Ziggy122]

That aint a good looking graph....

You can see that the post cat sensor is sort of following the pre cat sensor, which is telling me the Cat isn't doing its job no more

I'd wait till somebody like A1ant or SandB come and look

But to me - i'd be preparing for a new cat

Thats also assuming your sensors are okay and not false reading

The idle doing up and down isn't good either, should be fairly consistant

You haven't been playing with the Purge valve have you under the actuators test?

ziggy

 

[s and b]

needs a cat
last one indeed only one ive had needed cat had been off road with a young farmer going through poodles (he preferred sheep )
revving is caused by fiatecu scan
occasionally turning engine on and off with eobd lead disconnected cures it
tother times needs bat lead off

the graph to me shows the lambda loos trying to get the stoichiometric right

im not an expert

needs a 4 gas check
needs to make sure engine in good efficiency and not in need of a service

 

[KRaikkonenNo1]

No not played with purge valve at all.

Ok suspected MES was causing it, just wanted to confirm.

Is there anyway I can myself check that the lambdas are not fubared and it's not the cat?

Thanks.

 

[Ziggy122]

No not played with purge valve at all.

Ok suspected MES was causing it, just wanted to confirm.

Is there anyway I can myself check that the lambdas are not fubared and it's not the cat?

Thanks.

You need todo 1 of two things

Swap pre and post sensors over and observe to see if they read similarly

You might need to scope both sensors but tbh id be tempted to swap and see and base it on that

If you tap the cat with a toffee hammer does it rattle?

Ziggy

 

[KRaikkonenNo1]

You need todo 1 of two things

Swap pre and post sensors over and observe to see if they read similarly

You might need to scope both sensors but tbh id be tempted to swap and see and base it on that

If you tap the cat with a toffee hammer does it rattle?

Ziggy

Ok will do that and post back results from MES. That's if they budge - look seized up to me!

Have tried with a mallet and there is no rattling or noise to suggest a dead cat, also exhaust is still hitting against car as a results of clutch judder, surely this don't help either!

Thanks.

 

[atom0007]

You can't always tell the cat is dead by hitting it....it's not always obvious.

Mine looked ok, but was toast.

 

[KRaikkonenNo1]

You can't always tell the cat is dead by hitting it....it's not always obvious.

Mine looked ok, but was toast.

Yeah should of said I know it's not that obvious...imagine it was that easy, going round hitting everything with a mallet to see if it works

Anyway no wonder yours didn't work, using toast instead of a cat will never work..

 

[Ziggy122]

A cat way beyond saving will be breaking up, hence the mallet and tapping trick

Speed bumped cat's often rattle like that

Ziggy

 

[hisXLNC]

Hi everyone,
I had a check engine light about 6 months ago and found out it was the P0420 error. I thought it wasn't a big deal so didn't really plan to fix the problem. I have been experiencing poorer mileage (not anything crazy) and -I think- poorer performance, especially when going uphill. So everything suggests a new cat. I also had it checked by a mechanic who ran a fume test, and although I can pass an MOT, showed that my cat could be bad.
Before I change the cat, and give a fair amount of money for it, I want you to have a look at my o2 sensor readings and tell my what you think:

[ame="https://youtu.be/iO3Ver5hOTk"]https://youtu.be/iO3Ver5hOTk[/ame]

-Could it be a failing lambda sensor?
-The mechanic is offering me 2 choices, he will either cut open the exhaust manifold and replace the catalytic converter, or he can replace the whole exhaust manifold at once costing me a little bit more. Which one should I take?

 

[flisko]

its easier and should be cheaper to replace whole exhaust manifold which alredy contains cat, instead of cutting it open and welding again

 

[Charlieboy13]

Hi everyone,
I had a check engine light about 6 months ago and found out it was the P0420 error. I thought it wasn't a big deal so didn't really plan to fix the problem. I have been experiencing poorer mileage (not anything crazy) and -I think- poorer performance, especially when going uphill. So everything suggests a new cat. I also had it checked by a mechanic who ran a fume test, and although I can pass an MOT, showed that my cat could be bad.
Before I change the cat, and give a fair amount of money for it, I want you to have a look at my o2 sensor readings and tell my what you think:

https://youtu.be/iO3Ver5hOTk

-Could it be a failing lambda sensor?
-The mechanic is offering me 2 choices, he will either cut open the exhaust manifold and replace the catalytic converter, or he can replace the whole exhaust manifold at once costing me a little bit more. Which one should I take?

I personally would replace the whole manifold. Less margin for anything going wrong further down the line and I imagine it will last longer too.

I'm no expert, just my 2 cents!

Hope you get her sorted soon

 

[Ziggy122]

Id swap the 2 sensors over tbh

That pre cat sensor - i'd say is perfectly good

I'd be a little bit dubious that the post cat is flat lined....

I'd confirm post cat sensors working by swapping it over to see if it does a similar readout with them swapped or not

Ziggy

 

[hisXLNC]

I have replaced the pre-cat o2 sensor, and I haven't had the check engine light come up any more. It's been over a month and a significant amount of miles. I have had a fume test and showed that my cat is not in a very good condition but at least I'm not getting the fault code. Hope it helps...