[rob_f22]

Hey folks,

Over the weekend, I installed the HJS 300 cell downpipe. The new sound is incredible and I definitely notice the difference, although it is perhaps a bit too loud for my liking. It may be that I didn’t install it correctly so there is more sound escaping from the turbo and not going into the cat.

I noticed the car smelt quite bad having driven for two days now and I suspected that was just due to the new oils on the cat being burnt off. However, the exhaust fumes are getting quite bad and I suspected that there may be a leak somewhere. I checked the car for codes and found the following two new ones:

12B104: Lambda probe heating before catalytic converter, activation: open circuit
12B304: Lambda probe heating after catalytic converter, control: open circuit

So it looks like the O2 sensors aren’t working properly and I’ve ordered replacement Bosch OEM ones.

Was it possible these were damaged in the installation process and that is now contributing to the bad air/fuel ratio and therefore the higher emissions I’m smelling? I would’ve thought with the high flow cat that the smell wouldn’t be bad but it’s almost like I’m catless at the moment. No CEL until now though.

I was also considering resetting the lambda adaptations to see if that made a difference using BM3 but I didn’t think I’d have to.

[LA1Z24]

Do you have the o2 sensors plugged into the wrong connectors? The upstream connector has 5 wires, the downstream has 4

[thejeremyman9]

Originally Posted by LA1Z24

Do you have the o2 sensors plugged into the wrong connectors? The upstream connector has 5 wires, the downstream has 4

+1, check the plugs are correct. It's also pretty easy to damage O2s if you touch or drop them, etc.

[Shirazkhan]

Fault codes are open circuit,that could of registered when u unplugged them to instal the new downpipe,did u clear the fault code and see if they came back?