P0157 - SES only when Cutout is open.

My cousins '00 Firehawk gets the SES light everytime he opens his cutout(which is after the LT's and Catted Y pipe under rear passenger seat) and goes away shortly after he closes it. He got it scanned at Autozone and pulled up P0157, and the guy told him all of his O2's need to be replaced. But I told him to hold on before he spends his money.

P0157 - H02S Circuit Low Voltage Bank 2 Sensor 2.

Should he replace the rear o2's only or what? Could it be something on the engine? Maybe a bad Cat? And just in case it is related, the outer edge of his cutout has turned black.

Thanks.

tell him to just buy 2 O2's then a PCM flash from PCMforless..........that will get rid of his problem all together.

if it was a bad cat then it would trip the SES light even when the cut-out is closed.

his cut-out should turn black.........thats where all the exhaust comes out


his problem doesnt really make sense......it shouldnt be doing that, but if he does what i said above then he will be fine. How many miles are on the existing o2's??

Uh, why would he replace more than one O2 sensor? That code is only for a single O2 sensor. Try this:

http://www.gearchatter.com/viewtopic9043.php

Is his cutout before or after any of the O2 sensors? Even if it's after how close is it to the O2 sensor on the passenger side after the cat? Don't listen to the clowns at Autozone.

Abe

Uh, why would he replace more than one O2 sensor? That code is only for a single O2 sensor. Try this:

http://www.gearchatter.com/viewtopic9043.php

Is his cutout before or after any of the O2 sensors? Even if it's after how close is it to the O2 sensor on the passenger side after the cat? Don't listen to the clowns at Autozone.

Abe



Just because................thats why i asked how many miles were on the car.

sounds to me like he just needs the o2 sims for the rear sensors.

or just have it tuned out.

if the front sensors are still reading good...no need to spend the money yet

Well it sounds to me like he shouldn't have gotten cats. But that's my opinion. Where is the damn cutout? You shouldn't buy O2 sensors "just because", and if you spent the money on cats why would you tune out your rear O2's or get O2 sims? I am asking because I want to know, not because I'm being my usual jackass sarcastic self. Also, is his cutout electric or not? Just wondering about the placement of cutout and if it's electric....

Abe

It actually sounds like the O2 is working just fine. If it's that close to the cutout, then it's reading the outside air as a part of the mixture. Rich mixtures are reported with high voltage readings and lean mixtures are reported with low voltages. That combined with the fact that the SES light is only present when the cutout is open tells me the rear O2 sensor is picking up outside air in its reading. You don't need new O2's, new cats or a new tune. The rear O2's just tell the PCM if the cats are working or not. They have no effect on performance.

Why would he put it after the cat?

to bypass the muffler

one of the cats bolts directly to the manifolds on the LT1 and LS1...so it would be tough to put a cutout before it

Thanks for all the replies. Sorry I couldn't get on quicker but on Friday I went and checked it out and got under the car just to take a look before he replaced the o2's(which is what he was going to do) and find a hole in his exhaust after the cat and before the o2.
He must have hit something sharp or who knows what. But I am pretty sure thats what causing the problem. We'll see after he gets it fixed.

Here are some small crappy phone pics that show the hole, its about 1/8in x 1in.
http://img421.imageshack.us/img421/6074/image0401yi.jpg
http://img421.imageshack.us/img421/7251/image0382gj.jpg

Have a 2002 SS and installed Jet Hot LT's. After 20 miles it throws the p0410 primary air pump fault code. Any suggestions?

yeah...replace the AIR pump....or check the fuse.

or pull it all off, block the air tubes, clean up the engine bay and program out the code
:cool:

Did you get the LT's with the fittings for the AIR pump hoses?

Abe