Gregster1

Hi all,

Rcf owner in the UK here, no forums really going over here so hopefully you guys can help me.

I've struggled all day in my tiny inspection pit fitting the catback, un-resonated A'pexi system which looks and sounds fab. Problem is the engine light and trc off light are now on?

I don't know why given the cats are still there? Have I upset the lambda sensors somehow? Anybody else have this and how did you clear it? Can the fault codes be cleared a certain way?

Please help!
Taken the shine off my efforts today a bit, I have to admit

Cheers

Meraki Autoworks

iTrader: (8)

Recheck the o2 sensors when you reinstalled the exhaust. Common error to make the lights go off!

-Josh

Gregster1

Thanks Josh, check in what way though? They're both back in and nipped up. Does disconnecting the battery wipe errors?

4everkidd

iTrader: (2)

pull the + term on the battery for 15 mins... there will be a residual code if Lexus were to check but the CEL will disappear.

Sounds like they damaged one of the downstream O2 conditioners during install.

Gregster1

Thanks, I did the installation and the o2 sensors were removed without issue. Disconnected the battery and ran the car for 20 mins and cel has gone. Just hope it stays gone.

4everkidd

iTrader: (2)

takes 4 cycles usually for the code to return.

hopefully you got it figured!

Gregster1

By 4 cycles, do you mean 4 stop starts or something else? I have one of those obd2 reader/clearers on its way so I'll check and clear any faults logged.

Even with the light triggered, will the cars performance by negatively affected? I'm hoping that being post cat, probably not?

Meraki Autoworks

iTrader: (8)

If your car isn't going into limp mode (car starts off only in second gear and won't rev past a certain limit) your performance is fine but it will be annoying having those lights. Disconnecting the battery is one solution, or reset your engine lights with an OBD reader.

-Josh

Joe Z

iTrader: (10)

Only two things can cause this...

Exhaust leak at the manifold connection, due to the OEM crush gasket not seated correctly..

Or

One or Both of the O2 sensor wiring is wound up too tight causing a resistance in them or a low voltage reading..

Either of these will cause a CEL after installing an aftermarket exhaust..


Resetting the ECU or Battery will not solve these possible physical problems.

Joe Z

LXSDO

Take the info from the man who knows exhaust!

Gregster1

Thanks Joe, very useful info here. Do you refer to the first gasket that go between the exits of the downpipes? I think they're ok, I can't seem to notice a leak here. The wiring on the o2 sensors could be too wound though...

rmsimmonsj

iTrader: (1)

Exactly this. Most likely the latter reason. Check the wires and hopefully its fixable because the exhaust definitely doesn't turn on the CEL.

Gregster1

Thanks so much, I'd have never suspected that. I'll undo them, reverse twist them before putting them back in the boss so by the time they're fully screwed back there's no twist in the wires.

Great advice, thankfully received!

Meraki Autoworks

iTrader: (8)

Hope you figure out the issue!

-Josh

Gregster1

Quick update, I refitted the O2 sensors making sure the final seated position left the wires twist-free. Started the car again and no lights are coming back.

I also received my obd2 reader and there were no saved or pending errors at all so I wonder if it was just a hiccup.