[Ma v e n]

The EGT sensors are covered by powertrain, the DOC/DPF is 8/80

 

[14cruzeoilburner]

Driving south today in bitter cold, about -4ºF. I spent at least an hour of highway driving with the engine up to temperature. Halfway through the drive, the engine seems to start a regen cycle with fuel economy hovering in the 30s at highway or city speeds. The regen cycle was dragging on very long again, so I cycled the engine to restart and the regen continued. Driving an excessively long highway route to my parents' house did nothing to stop the regen.

Then, a block from their house, the CEL illuminates.

I guess today I'm going to the local auto parts store to get the code read, and then will see what happens after that. Overnight low might be down to -5ºF, so I'm going to fill the fuel tank up with a good dose of Power Service white bottle.

i had the same problem gen 1 2.0L diesel. Ended up going to the steelership. The reset the ECM and forced regen. Been perfect ever since. Of course it cost $125.00. They said there was nothing wrong with it. Frig-in A holes

 

[Barry Allen]

Dealership had the car all day today and the diesel technician worked on it. Second-hand report from his work (he already left for the day) is that he did multiple things and nothing seemed to indicate what the problem was or how to fix it. They did a regen cycle (probably forced regen, right there in the shop) to heat the DPF up and when everything was reporting it was hot as can be the temperature sensor was still reading low for unknown reasons. I've got the car back to go to work in the morning but they need it tomorrow afternoon to do more things, and the technician had multiple phone calls with tech support at HQ so maybe they'll have an answer.

The service writer did seem to think that the tech replaced the #1 sensor as part of his trouble-shooting. I asked him how he did that, because when I was contemplating doing it myself that same dealership told me they didn't have the part in stock and it would take until next week to get it. They didn't just pull a part out of their backside, so I don't think they replaced the sensor. I looked under the hood and it appeared to be the same sensor so I doubt it was replaced (yet).

 

[Barry Allen]

Today they cut me loose with the car while they order the sensor (should be there tomorrow). Their tech worked with GM at HQ and they think it's some sort of "glitch," which doesn't sound like a great explanation.

First, they said the tech tested the fuel and found biofuel in the tank. Well, no kidding, because every fuel station is selling biofuel. The ASTM specifications for diesel fuel were revised to include up to 5% without any labeling required, and then the stickers can be displayed on the pump for a 5-20% biofuel blend. Likewise, GM warranties the car for up to 20% biofuel.

They said the sensor appears to be reading fine but is still somehow causing problems, so they've confirmed it's under the powertrain warranty and they're going to replace it to satisfy GM as a warranty item to be billed that way.

 

[BodhiBenz1987]

Today they cut me loose with the car while they order the sensor (should be there tomorrow). Their tech worked with GM at HQ and they think it's some sort of "glitch," which doesn't sound like a great explanation.

First, they said the tech tested the fuel and found biofuel in the tank. Well, no kidding, because every fuel station is selling biofuel. The ASTM specifications for diesel fuel were revised to include up to 5% without any labeling required, and then the stickers can be displayed on the pump for a 5-20% biofuel blend. Likewise, GM warranties the car for up to 20% biofuel.

They said the sensor appears to be reading fine but is still somehow causing problems, so they've confirmed it's under the powertrain warranty and they're going to replace it to satisfy GM as a warranty item to be billed that way.

If you did end up with a substantial percentage of biodiesel, even if within the 20%, it's possible that it's gelling in the filter and causing issues with fuel delivery that would prohibit a successful regen. The fuel would ungel in the heated dealer shop, so they wouldn't see the issue when they did a regen. That's just a thought.
It could also be a "glitch" that hopefully a new sensor will solve. In my experience with my own regen issue (much different than yours but a regen issue nonetheless), there has yet to be any explanation but "glitch." I haven't updated my own thread in a while, but it's only gotten weirder. It's actually improved recently, but even that's weird.

 

[Barry Allen]

If you did end up with a substantial percentage of biodiesel, even if within the 20%, it's possible that it's gelling in the filter and causing issues with fuel delivery that would prohibit a successful regen. The fuel would ungel in the heated dealer shop, so they wouldn't see the issue when they did a regen. That's just a thought.

Hard to know. I can't tell if the dealership is replacing that sensor because GM tech support told them to do it, or if they're doing it to get everything they did billed as warranty work. The service writer did mention they wanted to get the technician paid for his diagnostic time, so it sounds like they want to bill this to GM instead of me again after they couldn't find anything wrong with my car blowing blue smoke out the tailpipe.

 

[Barry Allen]

If you did end up with a substantial percentage of biodiesel

There is literally no where that I can buy fuel without biodiesel in it. Every single pump all over town has the 5-20% stickers with the exception of my local HyVee grocery, and even then that fuel can have up to 5% without it being labeled as such. I have no way to purchase fuel that I know is exclusively petroleum.

 

[MP81]

I remember the last time I was in IL, we had to grab diesel and it was B20 - I know I was worried, at first, about if it would affect our fuel economy. The cold...wasn't quite an issue. It was like...100 degrees or something insane in May.

 

[Barry Allen]

I remember the last time I was in IL, we had to grab diesel and it was B20

I don't know any places that sell a specific 20% blend at retail. Oil companies have that as off-road fuel for farmers, but you can't get it from the pump. The stickers on all the pumps are 5-20% meaning you are probably getting 20% or close to it in summer and dropping down to 5% or less in winter. Minnesota runs 5% year-round as (I believe) the first state to require that in all diesel sold.

For about a 5-year span of time the state offered a motor fuel tax rebate for biodiesel blends of "greater than 10%." This meant 11% and that's why I got a fleet card account from an oil company so I could access their pumps for that fuel blend. The retailers of 11% got the motor fuel tax rebated so they could price their diesel lower and still pocket some extra profit, benefitting the owners and the oil company. But that tax break expired in 2019 and I don't think it was renewed (because our state is OUT. OF. MONEY.)

The 11% fuel blend only gelled up once when it was -22ºF and the oil company said they blended it to be good to -18ºF with the weather forecast. I never had any other problems with fuel other than a tank from Kroger that gave me some cold-weather misfiring and a tank from Philipps 66 that gave me lots of shuddering while using cruise control at slower speeds.

 

[BodhiBenz1987]

There is literally no where that I can buy fuel without biodiesel in it. Every single pump all over town has the 5-20% stickers with the exception of my local HyVee grocery, and even then that fuel can have up to 5% without it being labeled as such. I have no way to purchase fuel that I know is exclusively petroleum.

5% wouldn't be an issue, but 20% could be ... stations (or rather their suppliers) should adjust the percentage based on weather, and use appropriate additives in their fuel supply for the time of year. I'm just saying it's possible that a fuel supplier dropped the ball. I've had issues with the cars I rarely drive because I go through so little fuel that there's still summer fuel in them come winter. If it's persistently cold, it would only take one off batch as buildup in filters can be hard to break down even with de-gel treatments. It's just a thought, that if it persists, you could try changing the fuel filter early. Though I would think now that it's been in the heated shop it should be fully ungelled and wouldn't gel again as long as you don't have the misfortune of hitting another off batch.

 

[Snipesy]

shrug emoji

Biodiesel too new (to this scale) and too many different production methods.

 

[MP81]

If I recall, this was a Mobil station and it said B20 on the pump handle, but who knows what the "fine print" said on that label, since it was close to three years ago now.

 

[Barry Allen]

If I recall, this was a Mobil station

I found a Mobil station in 2018 that had a label on the pump stating the B20 diesel was a non-Mobil product - probably some local oil company blending B20 for bulk delivery, like is done to farmers. If it were a FS product, that's great. I passed because I didn't know where it came from.

There is a weird Shell station in the town north of me where the huge sign showing the prices says "DIESEL - NON-SHELL PRODUCT" in huge letters.

 

[Barry Allen]

The sensor will be here this weekend - it missed being ordered for whatever miscommunication.

GM technical support seems to think this is a combination of three separate factors:
1. Cold temperature - they said the code was set when the air temperature was -11ºF. That's not possible because it was not that cold when the CEL came on.
2. Short trip - they said the code was set when the engine was not up to temperature. That's not possible because I had driven the car for about an hour before the CEL came on.
3. Biodiesel - biofuel in the fuel blend. I don't know what to do about that because they warranty the car to operate on biodiesel, and I can't control what is in the fuel blend that I buy from the pump.

The car seems to be behaving itself now that the weather is a little bit warmer (in single digits this morning). I guess the dealership is replacing the sensor so they can get their labor covered under warranty coverage from GM. To do that, they have to replace the sensor even if it appears to be working correctly now and when they tested it.

 

[TDCruze]

I guess let them do their thing and hope it takes care of it. At least they are making an honest try at it!

 

[Barry Allen]

I guess let them do their thing and hope it takes care of it. At least they are making an honest try at it!

It saves me from paying the bill and there is a possibility I get the money back from the prior complaint (blue smoke out the tail pipe).

Makes me wish I had just ignored the CEL and let it go. After a couple weeks it would probably disappear on its own.

 

[Cruz15]

I have seen both Dcruzes I have owned not heat up properly when there is a heavy heat load on the engine. Cold temps and high heat setting coolant never came up to temp even after an hour of driving. I watch how much heat I ask from the engine and drive a little higher rpms when it is cold. If the coolant does not heat up after an hour then what about the oil?

 

[TDCruze]

It saves me from paying the bill and there is a possibility I get the money back from the prior complaint (blue smoke out the tail pipe).

Makes me wish I had just ignored the CEL and let it go. After a couple weeks it would probably disappear on its own.

Getting the money back from before would be nice.

That's why I usually clear them at least once to confirm the trouble, and rule out a fluke glitch. Especially when extremely cold.

I have seen both Dcruzes I have owned not heat up properly when there is a heavy heat load on the engine.

If the coolant does not heat up after an hour then what about the oil?

Yep, takes a looong time if ever depending on outside temp. A winter front over the grille helps, i had one on my gen 1. The gen 2 is much better, but below -20F it still struggles to get the engine up to temp.

Oil temp will be close to coolant since the oil cooler uses the coolant.

 

[Barry Allen]

Getting the money back from before would be nice.

That's why I usually clear them at least once to confirm the trouble, and rule out a fluke glitch. Especially when extremely cold.

I did clear the code. After that, it was back in regen when I pulled out of the parking lot because I figured the ECU was immediately running a regen to clear the DPF and to check if the temperature sensor was working. It was about 10ºF out and I took it for a highway drive on the loop around the city. At 55 mph it was achieving about 30 mpg and in regen for at least 20 minutes - then the CEL was on again.

 

[Barry Allen]

Oil temp will be close to coolant since the oil cooler uses the coolant.

Does the oil cooler have a thermostat for bypass? My Mazda RX-7 had an oil-to-air cooler and it had a thermostat that would open at 180ºF if I am remembering correctly. It bypassed (or mostly bypassed) the cooler if oil temperature was lower than that.