high flow exhaust causing codes

[Ben Kooken]

Hey guys, I just installed a high flow exhaust system with a new catalytic conveter and now my check engine light has come on.The shop i used ran a system check a code #40 appeared they had no idea what it means.I need help resolving the problem.The exhaust brought the truck alive and i don't want to go back to stock.Please help

[82_camaro_owner]

check the O2 sensor in the exhaust line if the removed that or diddnt properly reinstall it thats the problem. but its also easy to get a haynes book and ask. but if i were you id ask the place that pulled up the code and was unable to determine what it was what their problem is.

[Gearhead52]

Quite often when headers or a high flow system is added the O2 sensor woun't heat up enough to properly read the exhaust flow.

When I put headers on my 87 IROC-Z I had to put on a 3 wire heated O2 sensor. 3 wires came on later model vehicles, you didn't say, so if it has one you may need to change the computer chip or do a little reprogramming with an OBDII system.