Cat Fooler n54

Hi Guys,

Got my car back after water pump and thermostat needed replacement at SMG Tygervalley. Running great for past two weeks but three days ago engine fault light came on. After switching off and restart no fault noted but I took in to SMG. Fault code shows faulty oxygen sensor reading as I installed DP a year ago but no cat fooler fitted as no fault codes noted.
I was advised to either install cat foolers or get to a software intervention. Have any of you guys had similar issues with 335i N54 after downpipe installation?
 

husaindindar

///Member
A little odd that it ran fine for a year with a DP and no engine light.

It could be a faulty oxygen sensor and not because of the DP or lack of cat fooler.

Also on the E90 platform, there's many occasions of disappearing fault codes. I would try a diagnostic while the engine light is active, meaning don't switch off the car, rather keep it running and scan.
I've had vanos codes that only appeared while engine light was on.
 
Thanks, thought so myself. Dealership of the view that oxygen sensor is now fouling up due to cat removal. They cleared all fault codes and car running fine. Thing is, the fault message disappeared when I switched the car off and restarted a while later.
 

KarshS

///Member
On an N54.... Lots of errors get resolved by switching the car off and on again lol...

Best is to get MHD. Even if you dont want to tune atleast you can read the errors and datalog the o2 sensors.
 
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