Engine Light

herb-16v

hi everyone my light was on. i taken to garage then said was egr but mine blank off with the cheater. so he reset it and 2 day later back on agian went back same thing agian egr. so i got reader off ebay and whats come up is. P0420 Catalyst System Efficiency Below Threshold (Bank 1) but lookin round the net ppl saying cat and then ppl saying O2 Sensor. so dose anyone know what one it really is?????? notsure.gif

BURT150

If your a bit unsure of it unplug the o2 sensor drive it for a bit and see what code comes up and if its still the same code it'l piont you in that direction.

If it is that take the down pipe off and have a good look at the cat and pre cat if you still have one.

Also the o2 sensor should give you a certain voltage but im not sure what but im sure someone else will be able to tell you :thumbup:

herb-16v

BURT150 said:
If your a bit unsure of it unplug the o2 sensor drive it for a bit and see what code comes up and if its still the same code it'l piont you in that direction.

If it is that take the down pipe off and have a good look at the cat and pre cat if you still have one.

Also the o2 sensor should give you a certain voltage but im not sure what but im sure someone else will be able to tell you :thumbup:

thanks i will give it ago. pre cat was out before i got the car. i have had it 4 month now.

vocky

that code is for a lambda sensor, nothing to do with the egr system :thumbup:

as above, check the cat is ok or fit a new sensor after the cat

herb-16v

right i unplugged lambda sensor after the cat and come up with total diff code. so should i do same to front one now??? notsure.gif

herb-16v

right i have unplugged each sensor and got P0134 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1) P0135 O2 Sensor Heater Circuit (Bank 1 Sensor 1). so dose this mean its the cat with the other code that comes up

herb-16v

no one had this prob and know what it is? its not the sensors there done notsure.gif

MikeS

how does the car run

any misfire or cutting out ?

poor mpg ?

herb-16v

MikeS said:
how does the car run

any misfire or cutting out ?

poor mpg ?

car run fine no misfire or cuttin out or out. seem to use abit more petrol

vocky

could be the cat just isn't working anymore 🙁

still worth fitting a new lambda sensor after the cat as they are cheaper than buying a new cat :wtf:

herb-16v

vocky said:
could be the cat just isn't working anymore 🙁

still worth fitting a new lambda sensor after the cat as they are cheaper than buying a new cat :wtf:

hi mate yer done the lambda sensor reset light then few hour later light come back on 🙁

herb-16v

well i got a ported and polished throttle body and the engine light stayed out. so today i thought would change it back to standard and see if it come on. about hour and half later on comes the light with a p0420 Catalyst System Efficiency Below Threshold (Bank 1) code. changed it back to ported 1 and no light coming back on. scan it 20min ago and no codes coming up. so how is the throttle body stopping the light coming on when this code says about the Catalyst System Efficiency Below Threshold (Bank 1)??

make any sence to anyone??? notsure.gif

astra22bertoneauto

less air resistance through the engine > exhaust etc making the reading slightly above tolerance level hence no light.

As vocky said check both sensors & check cat not blocked/old. Also get rid of the precat if you have 1. Doesnt do any harm just to take it off and check. :thumbup:

herb-16v

yer thought mite be getting better air flow with that on. precat already gone when i got car 12month ago 😃