#1: Engine light - P0420 fault code Author: shoaky, Location: Sibiu, ROPosted: Sat Feb 26, 2011 3:28 pm ---- Hello guys,
I have a 2001 206 1.6 16v. My engine light came on a few months ago. At first I went to a friend of mine and had the fault code read. We’ve had it deleted at first but after 200 km the light came on again.
The code was:
Catalyst System Efficiency Below Threshold
P0420
Sensor 1 0700- 2.3% (3,9)
Sensor 2 0465- 99,2%
Since then we’ve deleted it several times, but the fault returned, not straight away but even sooner than first time. I checked all the pipes from exhaust, catalytic converter, manifold for leaks and I didn’t find anything; checked the spark plugs (bought 4 months ago), checked the wires of the 2 lambda sensors from the cat. Not experiencing any loss of power or an increase of fuel consumption.
I thought I’ll give it a try and post it here before I’ll have to buy anything.
Thanks. Last edited by shoaky on Thu Mar 03, 2011 11:22 am; edited 1 time in total
#2: Re: Engine light - help Author: SDK206, Location: Earth, most of the time!!Posted: Sat Feb 26, 2011 4:39 pm ---- From what you say, i would suspect the cat to be faulty. It has more than likely failed internally so no obvious way of telling visually.
Maybe worth checking emissions to see whats going on exactly regarding exhaust gases, this will tell you alot about whats going on
#3: Re: Engine light - help Author: shoaky, Location: Sibiu, ROPosted: Mon Feb 28, 2011 2:57 am ---- I should go for an emissions check then... but if the numbers are different on the check, could it be a situation in which one of the senors reading is wrong and it determines the cat to work different??
thank you and for any other ideas feel free to write.
thanks.
#4: Re: Engine light - help Author: NorthantsBen, Location: Raunds, NorthamptonshirePosted: Mon Feb 28, 2011 3:21 am ---- Does that mean above sensor 1 is reading poor emissions ???
If so is number one before or after the cat?
Also It's not uncommon for a lambda sensor to fail.
#5: Re: Engine light - help Author: shoaky, Location: Sibiu, ROPosted: Mon Feb 28, 2011 3:35 am ---- sensor 1 is above the cat. as for the reading of the emissions of the first sensor, I did not payed much attention at first. I'll do a scan again and check the values.
#6: Re: Engine light - P0420 fault code Author: shoaky, Location: Sibiu, ROPosted: Thu Mar 03, 2011 11:21 am ---- here's a print on the two sensors while the engine is running.
#7: Re: Engine light - P0420 fault code Author: gazza82, Location: South BucksPosted: Wed Jul 13, 2011 3:13 pm ---- I think sensor 2 is dead ... it should fluctuate as the internal heater switches on and off ...
Lambdas are a bit like spark plugs .. they have a life of about 60,000 miles. Also some of the cheaper non-original Lambda's are incorrect and they continuously record fault codes ... if it had a Bosch originally, fit another Bosch!
A lot of lambdas were destroyed in the UK when the petrol was contaminated ... can't remember which make but I think it was a supermarket.
#8: Re: Engine light - P0420 fault code Author: shoaky, Location: Sibiu, ROPosted: Fri Jul 15, 2011 3:45 am ---- interesting is that recently the fault code disappeared for 300 km and then came up again.
I will go have emissions checked and then read the code to pay a little more attention on sensor2.
thanks gazza82.
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