New exhaust system fitted last week and now I have fault code! Code inside...

[DJ_Troopa]

Hi everyone

Had a custom Longlife exhaust system fitted last week with a 200 cell sports cat from Style Dynamix who are down the road from me. My engine management light came up 2 days ago so i got it on my mates VAG-COM this evening and this is what it said..........

VAG-COM Version: Release 311.2-N

Control Module Part Number: 8N0 906 018 J
Component and/or Version: 1.8L R4/5VT 0004
Software Coding: 10710
Work Shop Code: WSC 13622
Additional Info: WAUZZZ8LX21001067 AUZ7Z0A1890544
1 Fault Found:
16804 - Catalyst System: Bank 1: Efficiency Below Threshold
P0420 - 35-00 - -



I've known the company for years and are very good so they won't mess me about with any problems. If somebody can point me in the right direction to resolve this i would really appreciate it!

My friend has cleared the fault off for now but i'm assuming it will return again at some point!

Thanks, hope you're all well


Jay

 

[S3 Paul]

I think bank 1 means the lambda probe before the cat. Might be wrong though,
I would check the wires to both the probs. and the plugs.

 

[DJ_Troopa]

Cheers Paul, going to my exhaust guys tomorrow to check it out.

I found this on Ross Wiki, what's your thoughts people?

16804/P0420/001056 - Catalyst System; Bank 1: Efficiency Below Threshold

Possible Causes

• Leakage in Intake and/or Exhaust System
• Catalyst faulty
• Oxygen Sensor(s) faulty
• Oxygen Sensor(s) Control faulty

Possible Solutions

• Check Intake and Exhaust System for Leaks
• Check Catalyst
• Check Oxygen Sensor(s)
• Check Oxygen Sensor(s) Control
  • Perform Oxygen Sensor(s) Aging Check

 

[<tuffty/>]

Classic fault code for sports cats.... the sports cat is less efficient than the OEM/std cat and the ECU thinks the cat has seem better days. The second Lambda is only really there to check the efficiency of the cat really so you can ignore it or try and get the supplier of any remap you may have to to code out the probe.

<tuffty/>

 

[S3 Paul]

I think i once saw an exhaust where the second lambda was sat away from the exhaust abit , fitted in a slight take off. so tricking the second lambda into getting a better reading.

 

[DJ_Troopa]

Classic fault code for sports cats.... the sports cat is less efficient than the OEM/std cat and the ECU thinks the cat has seem better days. The second Lambda is only really there to check the efficiency of the cat really so you can ignore it or try and get the supplier of any remap you may have to to code out the probe.

<tuffty/>

So if my light comes back on again with this fault, can i ignore it? Will it affect performance or the car in any way? That's the last thing i want happening! Thing is, it'll be hard to ignore with that bloomin light on and when the fault is wiped again it'll come back again after a while wouldn't it?

Thanks for that info!