Just wondering if an exhaust silencer could possible trigger a CEL? Basically yesterday I washed my car in my driveway, started her up to put her in the garage and no CEL on. Fast forward 4 hours later. I am getting ready to go to a pre-season football game with a buddy (we're taking my car) so I decided to put the silencer on. Start it up, CEL immediately comes on. I'm thinking no biggy so we continue to go to the game. Anyways, I get home from the game, remove the silencer, reset the ECU and no CEL. Today, again I just curiously I put the silencer in again to just run to the store. CEL came on again. Got home took it out, no more CEL. Can someone enlighten me on why/how a silencer would trigger a CEL? BTW, I am running a TP, single exhaust.

 

It will be very hard to tell without the Code from the CEL. It could be anything.

 

It's your test pipe...

 

I pulled the code and it was P0411 "Intake air injection" malfunction or something like that.

 

Do you have a test pipe?

 

Its not the test pipe. Its a loose vacuum line. It's a common CEL when you have an intake installed.

 

Problem fixed, thanks.