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catalyst code



well i managed to get hold of a code reader to see if it would diagnose why the electronic fault indicator light has come on and now preventing me from starting the car.
the code reader only popped up one code (this could also be for the decat though)....P0420. this has come up in the book as 'catalyst efficiency below threshold (bank 1)'.
this could to me sounds like what may pop up after a while once a decat is fitted...am i correct in thinking this?

also now the electronic fault indicator light has now stopped coming up on the dash however the light to the right (a red light with stop through it) has started flashing and once again the engine won't start. turns over fine but doesn't start.

anyone got any ideas?
 
  Focus RS mk1
the code is definatly for the de-cat, mine comes on every 500mile or so, just keep clearing it. the problem starting could be down to a faulty crank sensor or even an immobiliser fault
 
coollo. well i've cleared the decat code but no others exist on this basic code reader.
one thing i have noticed today is the voltage in the battery has now dropped to in the 11's...was told ideally it should be in the 12's or above. the car has been left without starting for over a week...gonna try jump starting it tomorrow and see what happens.

anyway i can find out whether its the crank sensor or immobiliser without taking it to a garage?
 
  Focus RS mk1
it should really start even in the 11s, when you put key in the ignition and turn ignition on check that the immobiliser light (red dot inbetween stop and service light) stops blinking, comes on then after a few seconds goes out. if so its ok and i would be getting the crank sensor changed
 
it should really start even in the 11s, when you put key in the ignition and turn ignition on check that the immobiliser light (red dot inbetween stop and service light) stops blinking, comes on then after a few seconds goes out. if so its ok and i would be getting the crank sensor changed

just been back out to the car to test what you mentioned regarding the immobiliser.
it runs through the same way you mentioned above so I guess I can rule that out.

i have noticed however that contrary to my most recent thread the car has reverted back to the original symptoms as mentioned in this thread. electronic fault indicator has come back. plug in the basic diagnostic reader i have and it brings up no codes.
if there was a problem with the crank case sensor would it bring up a code through the code reader?
also is there a way of testing the crank case sensor without replacing it (unsure of the cost and would rather replace if need be then just to check whether its faulty or not)?
 
  Focus RS mk1
when mine failed to the point it would start at all, my little code reader still had no code, i called out the aa and he plugged his laptop in and still showed no code, he told me change the crank sensor as he had seen it so many times before. think its around £50, you also get a new plug and loom. dnt go second hand! its well worth a try, and its a very high possiblity its that
 
it should really start even in the 11s, when you put key in the ignition and turn ignition on check that the immobiliser light (red dot inbetween stop and service light) stops blinking, comes on then after a few seconds goes out. if so its ok and i would be getting the crank sensor changed

when mine failed to the point it would start at all, my little code reader still had no code, i called out the aa and he plugged his laptop in and still showed no code, he told me change the crank sensor as he had seen it so many times before. think its around £50, you also get a new plug and loom. dnt go second hand! its well worth a try, and its a very high possiblity its that

thanks for the advice. just went out now...removed the airbox and had a good look at the crank sensor (guess there's nowt you can really check by having a look but still), and it doesn't look like the wires are damaged or even the connector.
however i've just remembered that leading up to the car completely dying and being in the state it is that it did become a bit difficult to start. it used to be turning over a lot more before it finally kicked in and started. had a look through other threads (searching for info on the crank sensor) and this sympton has also popped up so maybe just maybe this is the problem.

it also seems the new sensor (from renault) is now blue and not black and the loom is also different as apparently this was the cause of them failing.
is the plastic on your replacement one blue?
 
  Focus RS mk1
yeh mine is blue now, i think they have changed the design of the plug..... not sure tho. yeh lots of ppl have had this fault, mine started as a miss fire high up the rev range then got worse, felt like the engine was going to jump out the bay!! then eventually it cut out on the motorway and wouldnt restart at all
 
yeh mine is blue now, i think they have changed the design of the plug..... not sure tho. yeh lots of ppl have had this fault, mine started as a miss fire high up the rev range then got worse, felt like the engine was going to jump out the bay!! then eventually it cut out on the motorway and wouldnt restart at all

coolio mate. mine's still the black one so a possibility is a replacement part through renault. apparently its a modified loom so there must have been a problem with the original design.
going to remove it first then give it a good clean and see if that helps. if it does then i'll replace with a new modified one.

one thing though....did your electronic fault indicator or the engine warning light illuminate on the instrument panel once this fault set in and you were unable to start the engine?
 
  Focus RS mk1
coolio mate. mine's still the black one so a possibility is a replacement part through renault. apparently its a modified loom so there must have been a problem with the original design.
going to remove it first then give it a good clean and see if that helps. if it does then i'll replace with a new modified one.

one thing though....did your electronic fault indicator or the engine warning light illuminate on the instrument panel once this fault set in and you were unable to start the engine?

the electrical warning light use to flicker when the sensor was causing it to missfire. when it totaly failed i never really looked at the dash cause i was fuming like a typical man lol. it wouldnt start to begin with then after half an hour it started working again and never faulted again for the next 3 days when i replaced it, was weird but its cured now:D
 
well this evening I removed the crank sensor and gave it a cleaning hoping for maybe a start or at least no lights on the dash.
fail!...the electronic fault indicator was still on after turning the ignition on. the battery has also died (not surprising considering its been not running for over 2 weeks and has only been attempted to start so no charge has been going back in).
i'd rule out the battery and the crank sensor as if it was just that then surely the light electronic fault indicator light would have gone out.
ideally i'd like not to spend £50 on a new crank sensor only to find this still doesn't solve the problem.

anyone else got any suggestions as to what it could be?
 


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