Light on the dashboard..Need help!

[guybo]

You have a header back exhaust, you're untuned and you don't even have an OBD2 reader and Torque? Do you even have a wideband AFR gauge? Wow, good luck with that.

[R3b00T]

Originally Posted by steve99

Theirs the answer header change even catted header will usually trip P0420 cat efficiency CEL code.


It likely your cruise control will not work either.


maybe read Basic bolt on Mods guile linked below

It was installed 5weeks ago. Why would it light now and not right after it was installed?

[steve99]

Originally Posted by R3b00T

It was installed 5weeks ago. Why would it light now and not right after it was installed?

depends on type of driving and design of header and if its catted.


Ecu looks at reading from the front and rear 02 sensors and does some form of averaging calculation on data, if it differs too far from what it expects it will trigger the cel code. Its not unusual for it to take weeks to pop up.


Freeway driving or steady cruising tends to trigger it sooner.


It can also trigger due to exhaust leaks

[R3b00T]

Originally Posted by steve99

depends on type of driving and design of header and if its catted.


Ecu looks at reading from the front and rear 02 sensors and does some form of averaging calculation on data, if it differs too far from what it expects it will trigger the cel code. Its not unusual for it to take weeks to pop up.


Freeway driving or steady cruising tends to trigger it sooner.


It can also trigger due to exhaust leaks

Ty for the input.