Error Code P0030 and P0420

redarmy1929

Lads Im getting an error code P0030 Heater Control circuit bank 1 sensor 1

and P0420 Catalyst System Efficency Below threshold (bank 1)

I have been reading up on it, looks like i may need an new O2 sensor, are they expensive to buy?

would that cause the P0420 as well?

Thanks

joujoujou

What car?

P0420 is usually caused by faulty catalytic converter, which performance is controlled by 2nd lambda.

P0030 is indeed 1st lambda heating fault - if wires are well connected, then lambda's heating's died.

Occasionally catalytic converter/dpf can be brought to life if you run your car flat out couple of times.

redarmy1929

joujoujou wrote: »

What car?

P0420 is usually caused by faulty catalytic converter, which performance is controlled by 2nd lambda.

P0030 is indeed 1st lambda heating fault - if wires are well connected, then lambda's heating's died.

Occasionally catalytic converter/dpf can be brought to life if you run your car flat out couple of times.

sorry 03 Fiesta, are the lambda expensive do you know?

thanks

Nissan doctor

The P0420 code means that the post cat Lambda(sensor 2) is reading(switching) similar to the pre cat lambda(sensor 1) You need to study the live data readings to see exactly what the lambda sensors are measuring but the P0420 code means that the cat is now faulty, however you need to find the cause of the cat failing.

The P0030 fault may be the lambda itself or it may be the wiring or plug to the lambda. You would need to test it (or have it tested) by checking resistance across the heating element wires.

The heating element fault is unlikely to have damaged the cat though unless it has been faulty for a long time as this doesn't effect the function of the lambda once its fully up to temperature, only when the engine is cold.

joujoujou

redarmy1929 wrote: »

[...] are the lambda expensive do you know?

thanks

The new one is dear. Second hand one would cost you some 40-50 eur + fitting.

Nissan doctor wrote: »

[...] the P0420 code means that the cat is now faulty [...]

More than likely, yes. But I had issues with some cars ran too slow (personally I call that "granma's driving style") and after been ran flat out cat's been unblocked and failure's gone.

Once even got something like this:

https://www.youtube.com/watch?v=UDhtaH6Isyg

Syllabus

joujoujou wrote: »

The new one is dear. Second hand one would cost you some 40-50 eur + fitting.............

why would u ever want a 2nd hand O2 sensor


places doing new(not branded) O2 sensors for about 100

joujoujou

Why not? :P

I have one 2nd hand fitted already and it's fine, so don't understand why would I pay more?

dieselbug

Make sure you dont have a fault in the heater feed circuit before condemming the sensor. This circuit is shared by both pre and post cat sensors and if faulty to both will acccount for the cat efficiency code also. Although you dont appear to have a fault code for no2 heater, I would still check.

Circuit is on fuse no 13 but needs to be checked at sensors.