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Starsekr · 08-05-2020, 10:44 PM

Getting code P0151 on the Scan Gauge, found the exhaust fitting on the drivers side, just in front of the O2 sensor, had a stripped bolt and a small gap. The donut looked ok, so used a Grade 8 bolt, washers and nuts to fix the gap. It pulled up tight without problems. But once again, on a recent 250 mile trip, I got the check engine light and P0151 code again. (engine warmed, slow acceleration to 65 mph, same symptoms as before, code cleared and did not reappear)...so reading on here, the P0151 is for Bank 2 Sensor 1, and my leak was in Bank 1? Please confirm id of Bank 1 and Bank 2 positions. I had the engine replaced last year, where the bolt probably got stripped. Could the sensor leads have been switched too? How do I tell?

Arch Hoagland · 08-05-2020, 10:51 PM

I fought a P0151 code problem for over a year.

Very long story short....the MAF was dirty.

Clean your MAF...very common problem on the 8.1

Starsekr · 08-06-2020, 09:52 PM

Arch, cleaned the MAF. Almost too old to climb inside that wheel well

. MAP idle reading on my scan gage before was 5.1 with the AC on, and 4.8 afterwards with the AC on. Not a lot of change. Can't get on the road to try to duplicate problem for about 3 weeks or so.
I have 2 new O2 sensors coming (Amazon had 2 for $34 free shipping and returnable) but won't install them until a road test.
So back to my original question. Is bank one on the driver's side and bank two on the passenger's side? I guess I can slide under and disconnect an O2 sensor and start it up to see what codes I get.

Arch Hoagland · 08-06-2020, 10:07 PM

It's been a while but the one I changed was on the passenger side. It didn't cure the problem.

There was a hill just north of Salinas California that would trigger my P0151 code EVERYTIME I went over it. Handy for troubleshooting.

Problem was...it was 130 miles from my home. So any testing was a 260 mile trip. Kids lived there so we went a couple times a year.

You need a special socket to remove the O2 sensor and you need to soak it the night before with PB Blaster.

Started getting P0151 and P0152 codes on a trip to Utah. Every hill caused it.

Got to SLC and a repair place there cleaned the MAF and it took care of the problem instantly plus I gained a lot of power back.

vettenuts · 08-07-2020, 05:52 AM

Bank 1 is the driver’s side, bank 2 is passenger. Sensor 1 is before catalytic converter.

CJ7365 · 08-07-2020, 06:42 PM

Quote:

Originally Posted by vettenuts

Bank 1 is the driver’s side, bank 2 is passenger. Sensor 1 is before catalytic converter.

Vettenuts, I was reading on another thread and noticed that you upgraded to a Phaeton.

I'm glad to see your still contributing to the WH forum and hope you continue to do so.

Congrats on the New RV.

vettenuts · 08-08-2020, 06:15 AM

Quote:

Originally Posted by CJ7365

Vettenuts, I was reading on another thread and noticed that you upgraded to a Phaeton.

I'm glad to see your still contributing to the WH forum and hope you continue to do so.

Congrats on the New RV.

Thanks, still have a soft spot for the Workhorse. The Phaeton is a beautiful coach, but it's a lot more complicated than the Workhorse and it's been a real learning experience.

Randalpho · 08-08-2020, 11:37 AM

Bank 1 on any OBD vehicle is the side that cylinder #1 is on. I googled "firing order GM 8.1" and it comes up with cylinder #1 being on the drivers side. So bank 2 would be the passenger side. And also what Vettenuts stated, sensor 1 is upstream (before the cats) and Sensor 2 is downstream (at or after the cats).

Sensor(s) 1 is for Fuel Control (rich/lean) and Sensor(2) is for Catalyst Efficiency (is the cat working properly).