Oxygen sensors failing on 2018 Silverado 3500

[clinebarger]

The exhaust needs to be looked over carefully for hairline cracks in the vicinity of the B1S2 O2.

The P2270 diagnostic test is ran only upon initial decel, The PCM knows the post catalyst O2's will be driven rich.

It would be a pretty small leak, A big leak would cause a P0137 in conjunction with P2270.

Assuming OE sensors are being used.....Hard time believing you have 3-4 bad sensors (If I'm reading the original post correctly?)

Might be prudent to swap the 2 post catalyst sensors if no leaks can be located.

The HO2S Heater Resistance Learned Values are supposed to be Reset anytime a O2 is replaced, A often skipped procedure.

 

[Phishin]

This morning my mechanic pressurized the entire exhaust system and found a small leak at the exhaust manifold.

Next week the entire exhaust system will be removed and new exhaust manifolds on both sides will be replaced with new studs and all other exhaust connections will be resealed with new gaskets.

 

[Phishin]

The cost of removing the entire exhaust system and installing new manifold gaskets and new gaskets at the down tube will be approximately $850. The light has stayed off since I've gotten home from this trip.

HOWEVER, tomorrow I am pulling an empty trailer to Southern Kentucky (350 miles each way) and dragging home a Kubota tractor and attachments. This might just be the test I need to see if I really do need to get this addressed (spend the money). If the CEL stays off, I just might cancel my appointment for Monday's service.

The pressurized smoke test preformed on the entire exhaust system did NOT show any leaks around the sensors or elsewhere in the exhaust....ONLY a small leak at the manifold. I'm not sure what I'm going to do.....

 

[Exhaustgases]

Maybe look for a wiring issue, connector etc. ? Lean for an O2 is a low voltage.

 

[SureshR]

> The code is P2270 -- O2 Sensor Signal Biased/Stuck Lean - Bank 1 Sensor 2

Too much oxygen. Or your engine IS running lean due to an exhaust leak between the first and second sensors.

I'd check - in sequence

1. Air filter and MAF / oxygen sensors
2. Injectors (clean or replace)
3. Exhaust leaks (seal using putty / heat wrap for minor leaks or see if it is worth replacing)

Eh ok, it was an exhaust leak I see. Glad that's sorted.

 

[clinebarger]

Maybe look for a wiring issue, connector etc. ? Lean for an O2 is a low voltage.

This is a component performance DTC not a circuit fault DTC.

 

[clinebarger]

The cost of removing the entire exhaust system and installing new manifold gaskets and new gaskets at the down tube will be approximately $850. The light has stayed off since I've gotten home from this trip.

HOWEVER, tomorrow I am pulling an empty trailer to Southern Kentucky (350 miles each way) and dragging home a Kubota tractor and attachments. This might just be the test I need to see if I really do need to get this addressed (spend the money). If the CEL stays off, I just might cancel my appointment for Monday's service.

The pressurized smoke test preformed on the entire exhaust system did NOT show any leaks around the sensors or elsewhere in the exhaust....ONLY a small leak at the manifold. I'm not sure what I'm going to do.....

Don't have the entire exhaust removed. The manifold bolts are the weak link. New OE manifolds & Gaskets along with ARP 134-1102 bolts are a good idea.

Manifolds are done through the wheel wells.

 

[Phishin]

Don't have the entire exhaust removed. The manifold bolts are the weak link. New OE manifolds & Gaskets along with ARP 134-1102 bolts are a good idea.

Manifolds are done through the wheel wells.

The truck was serviced last week. New manifold bolts and gaskets. And all the gaskets throughout the exhaust system.

The next day I pulled a big trailer 2k miles through the mountains and no CEL. I hope it's fixed. They reused the same manifolds.... and used fresh GM bolts.

 

[TheLastWord]

Covered by emissions warranty? Your state may differ from mine.

EDIT: Noticed you said 140K so no warranty.

$20K for a Cub Cadet!!!

This guy can't even give one away:

Cub Cadet Enduro XT1 - farm & garden - by owner - sale - craigslist

Used Cub Cadet Garden Tractor for parts.

sandiego.craigslist.org

Looks low miles. "They don't make them like they used to".