focus engine management light

enfield_freddy

2004/5 focus 1.6


give it some welly last week , engine light popped on and stayed on


p0420 , catalyst efficiency below threshold (bank 1) , that's what the book that comes with the OBD11 reader says


had problems for the last few yrs getting the emission's thru the MOT , had to use another car sat in the garage


light now cleared , new cat or what? , or is the code relating to something else

colino

Check the exhaust system from block to tailpipe for any tiny leak. Much more likely to be a leak than a knackered cat (very rare) but many dodgy garages love the generic P0420 as it is a licence to print money from the ill-informed.


Edit. What did you mean about using another car in the garage?

enfield_freddy

ok , the manifold/downpipe forward of the cat was leaking for a while , this has now been replaced about 12 mths ago garage blamed this for the high emmisions , stuck an advisory on but past it , was this the reason for the cat (if indeed this is the correct fault) failure ?


other faults in last 3 yrs was 2 (yes 2) coil packs failing and bad misfire




Edit. What did you mean about using another car in the garage?


the MOT guy took a reading off his own focus

gabitzul

enfield_freddy wrote: »

the MOT guy took a reading off his own focus

Needless to say, you do realise it's illegal and both you and the very kind chap who did this could get in trouble?...

enfield_freddy

yup possibly ,however he does like the odd can of lager

s_b

the scenario
dedadedada
coils breaking down car misfires unburnt fuel goes in cat and over time kills it
leak in exhaust at this time red herring
mot man risked losing his badge to get a car through mot because hes an alcoholic
new cat fitted of dubious quality and probably illegal to boot if car manufactured after 2001
this new cat has failed within a year because its sub standard does it have the certificate of conformity on it?

enfield_freddy

well if you read again a new cat HAS NOT been fitted , just a replacement manifold with a flexi pipe on it.


are you saying the cat has now failed , 18 mths after the faulty ignition , and 12 mths after the damaged "flexi" pipe (before the cat) was fitted .


PS , the garage owner is not as you state a "alcoholic"

colino

Top marks OP, using a garage that can't get one of the commonest cars in the UK through an MOT so cheats and lets you boast about it online.

enfield_freddy

colino wrote: »

Top marks OP, using a garage that can't get one of the commonest cars in the UK through an MOT so cheats and lets you boast about it online.

thank you for your helpful post , I will study them this evening and try to work out which one will fix my car the most economical way

arcon5

Sounds like a new cat is needed, yes.
The code will be based on similar results being produced by both lambda sensors, so yes it's cat specific.
BUT the cats more than likely a symptom.

A multimeter and a test light (one with an earth lead) are cheap enough. The former will test the injectors. The latter can test the strength of the spark and be run over HT leads which will easily and quickly show you if there is a voltage leak

enfield_freddy

thanks arcon5 , lamba sensors , you say 2 of them , I can only see one listed , this seems to screw into the cat .


the car was returned to the garage that sold it to me after about 3 mths , with a misfire , he replaced the coil pack with a used one , about 6 mths later the replacement unit failed , so I got a new one from euro car parts , I also changed the plugs , leads and air filter for new ones .


the exaust flexy on the manifold started to leak , so this was replaced after about 3 mths