P0157 trouble code help?

Tech discussions on the L77 6.0L V8.
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CrashTestDummy
Posts: 1802
Joined: Sat Feb 07, 2015 8:31 pm
Location: Pearland, Texas

P0157 trouble code help?

Post by CrashTestDummy » Fri Feb 15, 2019 11:58 pm

I finally got a chance to get the car on the road the other day. About a mile in, the CEL comes on. I check the codes and it's a P0157! The car runs fine, otherwise. What I've done:

Solo Performance high-flow cats.
X-Force Varex exhaust system.

Note that the cats come with an O2 sensor extender to get the secondary O2 out of the exhaust flow a bit to make it think things are okay. I've also wired the fog lights per Steve's kit, which required pulling the under-hood fuse block to add some circuits. That's all I've done that I think could affect the O2 system.

What do I look for, or what do I test? Or am I screwed with the addition of the cats and exhaust?
Gene Beaird,
Pearland, Texas
2012 Caprice 9C1
1992 B4C 1LE Camaro
2010 Tahoe PPV (her car)
1995 DGGM Impala SS
1996 BBB Impala SS (11-second DD)
1985 Firebird - 310 LS1 C Prepared autocross car.
And some others
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Sanford
Posts: 76
Joined: Tue Dec 13, 2016 3:38 am
Location: Texas Gulf Coast

Re: P0157 trouble code help?

Post by Sanford » Sat Feb 16, 2019 1:15 am

Need to get ahold of a scan tool that reads data. Take a look at what the other bank is reading and see if the readings are close to each other or if there is a drastic difference.
The other method would be to swap the post cat sensor to the other bank and see if it sets a code for that bank.

David C.

CrashTestDummy
Posts: 1802
Joined: Sat Feb 07, 2015 8:31 pm
Location: Pearland, Texas

Re: P0157 trouble code help?

Post by CrashTestDummy » Sun Feb 17, 2019 9:44 pm

Finally got some time out in the garage. I hooked up the OBDII reader, I'm using OBDLink, and I'm seeing the O2 voltages for the Bank 1 Sensor 2 reading a solid 0.06v. It never changes. The Bank 2 Sensor 2, however, varies between 0.015 and 0.02v. The pre-cat sensors seem to be working okay.

Is my Bank1 Sensor2 dead?
Gene Beaird,
Pearland, Texas
2012 Caprice 9C1
1992 B4C 1LE Camaro
2010 Tahoe PPV (her car)
1995 DGGM Impala SS
1996 BBB Impala SS (11-second DD)
1985 Firebird - 310 LS1 C Prepared autocross car.
And some others
Do YOU have my SPID?

Sanford
Posts: 76
Joined: Tue Dec 13, 2016 3:38 am
Location: Texas Gulf Coast

Re: P0157 trouble code help?

Post by Sanford » Mon Feb 18, 2019 2:37 am

If the output of the sensor did not change from the time you started the car through the warm up time, it sounds like a dead sensor, unless you have a wiring/connection problem. I would just swap the after cat sensors and see if it readings follow the sensor. If the fixed reading moves to the other side, you have a dead sensor.

David C.

CrashTestDummy
Posts: 1802
Joined: Sat Feb 07, 2015 8:31 pm
Location: Pearland, Texas

Re: P0157 trouble code help?

Post by CrashTestDummy » Sun Mar 10, 2019 10:38 pm

Well, got that O2 sensor replaced. After running the car a bit, the CEL didn't turn off, and I was apparently not clearing it properly. The position 2 no. 2 sensor was showing about .01-.05 v while driving, I swapped the one I had just pulled off to the other side. It didn't seem to make much difference in the readings. I DID get the code cleared, and need to take the car out for a longer drive to see if it comes back on, but in the meantime, I'll get a replacement O2 sensor on it's way, just to be hopefully safe.

It WAS nice to be able to get out into the shop today, even though the humidity was so high the moisture condensed on the floor. :shock:
Gene Beaird,
Pearland, Texas
2012 Caprice 9C1
1992 B4C 1LE Camaro
2010 Tahoe PPV (her car)
1995 DGGM Impala SS
1996 BBB Impala SS (11-second DD)
1985 Firebird - 310 LS1 C Prepared autocross car.
And some others
Do YOU have my SPID?

CrashTestDummy
Posts: 1802
Joined: Sat Feb 07, 2015 8:31 pm
Location: Pearland, Texas

Re: P0157 trouble code help?

Post by CrashTestDummy » Mon Mar 18, 2019 3:36 am

Ended up replacing the other secondary sensor, just to be safe. Took the kids out for a drive with the ODB reader connected. It looked good, and we didn’t set the MIL off. I’ll drive it a few more times, then get it inspected. Fingers crossed.
Gene Beaird,
Pearland, Texas
2012 Caprice 9C1
1992 B4C 1LE Camaro
2010 Tahoe PPV (her car)
1995 DGGM Impala SS
1996 BBB Impala SS (11-second DD)
1985 Firebird - 310 LS1 C Prepared autocross car.
And some others
Do YOU have my SPID?

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