# P0133 and a sooty O2 sensor



## ChevyGuy (Dec 13, 2014)

beaurrr said:


> How about the resetting the trim values? Does that mean they flashed in some kind of permanent update?


I don't read that as a permanent update, but something that tells the computer to start with factory values and not use the values learned while the sensor was dirty.

It sounds like what could be happening is that the sensor gets dirty and starts to signal that the engine is too lean. So the computer enriches the fuel, causing the sensor to get even more dirty. The downward spiral continues until you get a CEL. It appears the solution is to replace the sensor with one that isn't as affected by soot an then reset the computer.

But that's just a wild guess.


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## Tomko (Jun 1, 2013)

Italian tune up on new parts is counterintuitive. 

How many miles?


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## ChevyGuy (Dec 13, 2014)

Tomko said:


> Italian tune up on new parts is counterintuitive.


Yeah, but maybe not a bad way to get the computer to dial in the engine from factory default.


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## beaurrr (Aug 27, 2016)

Tomko said:


> Italian tune up on new parts is counterintuitive.
> 
> How many miles?


19,500. 
Italian tune-up was geared to the other downstream (and likely sooty) sensors that weren't replaced.


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## oilburner (Jun 13, 2013)

beaurrr said:


> 19,500.
> Italian tune-up was geared to the other downstream (and likely sooty) sensors that weren't replaced.


all sensors downstream of the DPF will be clean.


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## beaurrr (Aug 27, 2016)

oilburner said:


> all sensors downstream of the DPF will be clean.


Right; I meant the upstream NOX and EGT sensors, in addition to the now-replaced O2 sensor.


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## sailurman (Sep 29, 2016)

Just curious, at 19500 you have probably received 2 oil changes. Did you confirm specifications of the oil used? My dealership was pretty clueless the first time I came in. I've been told that improper oil can be associated with premature soot build up on sensors and DPF. Correct me if I'm wrong.


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## beaurrr (Aug 27, 2016)

sailurman said:


> Just curious, at 19500 you have probably received 2 oil changes. Did you confirm specifications of the oil used? My dealership was pretty clueless the first time I came in. I've been told that improper oil can be associated with premature soot build up on sensors and DPF. Correct me if I'm wrong.


I wish I knew. It had oil changes at 4k, 10k, 18k and 20k. The first two were by the previous owner. The one at 18k was by the dealer that sold me the car, and the last one was a different dealer (one who lives in the same city as me).
The only work order I have is for the one at 18k, which says "15w-40" but then gives the correct part number of dexos 2, even though that oil apparently does not exist in that weight. I posted about this a couple months ago. I'm not sure what oil it actually had in it, but I do know it was a good inch over the full mark.
I had another oil change 2,000 miles later as part of the 'free maintenance'. I have not seen the work order because the service advisor said the manager was backed up and wasn't around to approve the other work they were doing at the same time, and they'd just mail it to me....or something like that. When I asked the service advisor about the oil, I got a pretty good brush-off, and I really didn't feel like making a big deal out of it.
I'll use the remaining free oil changes (if I have any), then do them myself from here on out.

Basically, I have no idea what oil has been put in, ever.
Who advised you that the wrong oil can soot up the DPF?


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## mkohan (Dec 19, 2015)

I believe any oil with ash in it will cause problems to the emission system. DEXOS 2 is preferred but ACEP C3 approved is acceptable.


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## diesel (Jun 8, 2013)

There are a few things that happen with a high SAPS oil. First off, it has a higher ash content, and the DPF cannot cope with that over time. It naturally produces ash as a result of the regen process. Adding extra ash into the mix isn't a good thing. I found a few things on google about this, but nothing really good and detailed. 

Also, the wrong oil will not be able to cope with the amount of soot that is produced by a diesel engine, that gets stored in the oil. you might notice that 5 minutes after a fresh oil change, the oil is black. 

There's not really anything definitive that I could find about a sensor sooting up compared to which oil is used.


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## sailurman (Sep 29, 2016)

Research online.


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## beaurrr (Aug 27, 2016)

Naturally, when I change my oil, I'll use dexos 2 oil or an ACEA C3 rated oil. As for whatever the dealer put it, well, I'll never know.

If the service order says "15w-40" and has a dexos 2 part number, which is it? It can't be both.


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