Oil Life Monitor

[Ernessch]

I  contacted the dealership service department and was told this 91% after 185 miles no matter the conditions is not normal and I am to bring the truck in for service as soon as I can and watch it closely until then. 

[JimCost2014]

On 7/8/2020 at 4:20 PM, Ernessch said:

I  contacted the dealership service department and was told this 91% after 185 miles no matter the conditions is not normal and I am to bring the truck in for service as soon as I can and watch it closely until then. 

I think your truck is fine.

 

The computer is still learning your driving habits, and the last thing it has to go off of is a 14 month 300 mile oil change.

 

As you put more miles on it, it will adjust accordingly, but if your oil looks milky, or you are losing/burning a lot, then I would be concerned.

 

You will notice this same scenario on your fuel mileage between tanks, depending on the type of driving you were doing. All city, it will tell you 300 + miles for the tank, all freeway maybe 450 + miles as examples.

Edited July 27, 2020 by JimCost2014

[Ernessch]

Update to original post. 

I've now driven 440 miles since the dealer changed the oil. My percentage has dropped to 81%. I do not drive that often and when I do it's mostly city but not stop and go. I do not let my engine sit and Idle. It's hot here in Oklahoma but most of my driving is in the mornings when the temperature is in the 80's. I live in an area that isn't that congested. I have made sure I take a highway trip of about 20 mile at least weekly to get a good reading of my oil life monitoring system before I hurt my engine or the warranty runs out. 81% can not be correct based upon my reading of  GM papers on this system. Even under extreme circumstances I should get 3000 miles and that's with pulling a heavy trailer or heavy off road use. Per the GM posts and my driving style I should be getting 7500 or more miles. Please dont ask me to cite those papers because I can't find them on my web searches for this post. At this rate of normal old guy driving a web per cent calculator says I'll get 2315 miles between oil changes. This will be my last vehicle and I do not want to harm it if there is a problem. Also changing the oil every 2300 miles is not an option. My oil is clean and I check it before I drive it until I figure this out. I guess my question is, is this anywhere near normal? Can the dealer do anything about it? Is there any defect inside the engine computer that is causing these numbers? Can I reset the entire thing by disconnecting the battery and see if that helps? Can the GM algorithm software be wrong and need to be recalibrated by the dealer?  Should I reset the Oil Monitoring System per the manual and try again? I'm not enjoying my new truck because of this issue. Sorry for the many questions but I'm not happy with this drop in Oil Life per the GM technology monitoring of my vehicle oil life. 

[davester]

How long has it been since your last oil change?

[Ernessch]

440 miles. 

Edited July 26, 2020 by Ernessch
Mistake

[Ernessch]

29 minutes ago, davester said:

How long has it been since your last oil change?

440 miles. 

Edited July 26, 2020 by Ernessch
Mistake

[davester]

I meant how many days/months/years since the oil was changed?

[Ernessch]

17 minutes ago, davester said:

I meant how many days/months/years since the oil was changed?

6/9/2020 which is 48 days. My original post was 7-8-2020.

Edited July 26, 2020 by Ernessch

[Z45]

IMO you are wasting too much time worrying about this.  Drive it and don't pay so much attention to it. 

The oil life monitor is based on a mathematical model. A computer chip in the Powertrain Control Module is loaded with a certain number of engine revolution counts. The count for each engine/vehicle combination is determined by testing. As the engine runs, each revolution is subtracted from the remaining count in the oil life monitor. When the count reaches zero, the instrument panel light comes on. But, when the various input sensors detect that the engine is running under either cold or hot conditions, it subtracts extra counts (penalties) for each engine revolution. So, the conditions that cause the oil to "wear out" make the counter run down faster.

[Ernessch]

4 minutes ago, elcamino said:

IMO you are wasting too much time worrying about this.  Drive it and don't pay so much attention to it. 

The oil life monitor is based on a mathematical model. A computer chip in the Powertrain Control Module is loaded with a certain number of engine revolution counts. The count for each engine/vehicle combination is determined by testing. As the engine runs, each revolution is subtracted from the remaining count in the oil life monitor. When the count reaches zero, the instrument panel light comes on. But, when the various input sensors detect that the engine is running under either cold or hot conditions, it subtracts extra counts (penalties) for each engine revolution. So, the conditions that cause the oil to "wear out" make the counter run down faster.

 

So a drop of 18% in 440 miles of normal driving is considered appropriate. If I continue driving normally I should be at 50% at 1000 miles. Thanks. I'll order oil by the barrel. 

[diyer2]

What did you do with the vehicles you owned previous to this one if they didn't have an OLM. Agree with elcamino, stop fusing and use the old method. Write down the miles and change it at the mileage you're happy with. That's what I do. I do it because I won't run oil 7500 miles and I don't need a computer to tell me when to change my oil. You do it if you desire. 

 

[JimCost2014]

28 minutes ago, Ernessch said:

So a drop of 18% in 440 miles of normal driving is considered appropriate. If I continue driving normally I should be at 50% at 1000 miles. Thanks. I'll order oil by the barrel. 

I think you are going to have to drive it for a while (thousands, not hundreds of miles) before it will have a baseline to go off of.

 

Look at how many miles on the truck, and look how infrequent (time between) the oil changes were done. I would just run it to 5000 miles and see where it is, get it changed and reset it then.

[flyingfool]

am i wrong to assume ...even if you dont drive it, the oil meter life should be declining... combustion  process taints the oil and makes it acidic. thus needs to be swapped out atleast once a year even if you dont drive at all

[Z45]

51 minutes ago, Ernessch said:

So a drop of 18% in 440 miles of normal driving is considered appropriate. If I continue driving normally I should be at 50% at 1000 miles. Thanks. I'll order oil by the barrel. 

You cannot assume that a 18 drop in 440 will continue.   You could go the next 440 miles and it drop 2%.  You cannot make assumptions,  its non-linear. 

 

Its a computer algorithm running in the pcm, sometimes there is NO rhyme or reason for these things.  

 

non-linear. If you describe something as non-linear, you mean that it does not progress or develop smoothly from one stage to the next in a logical way. Instead, it makes sudden changes, or seems to develop in different directions at the same time.

Edited July 26, 2020 by elcamino

[Z45]

22 minutes ago, flyingfool said:

am i wrong to assume ...even if you dont drive it, the oil meter life should be declining... combustion  process taints the oil and makes it acidic. thus needs to be swapped out atleast once a year even if you dont drive at all

Yes, if the engine is not running its not working.

Condition/Concern

Since 2010 all GM vehicles have been equipped with the oil life monitor (OLM) system

The monitor calculates the percent of oil life remaining, based on 3 pathways

The OLM starts its calculation for all pathways after the first 50 miles to account for marshalling and time before sale.  Subsequently, calculations begin immediately after each reset.

Recommendation/Instructions

 

Oil Life Monitor Calculation Pathways:

1.      Engine revolutions- Oil life starts with a fixed number of revolutions and will decrease with each revolution.  Cold / hot coolant temp readings have multipliers that reduce engine revolutions pathway quicker depending on how far from the normal oil temperature the vehicle is operating.

Note: If engine coolant temp gets above 260F, engine overheat condition, the oil life will go to 0%.

2.      Mileage from last reset – Starting with MY 2013, the OLM is capped at 7500 miles for all GM powertrains except the Volt.  In perfect conditions a vehicle would reach 7500 miles from the last reset and the oil life left would be 0%.

3.      Time- This pathway is a liner function, a fixed decrease in oil life for a given time after the oil life is reset.  The oil life will drop to 0% after 1 year regardless of the amount of engine revolutions or how many miles since the reset.

Note: The Volt uses a 2 year timer instead of 1 year. It also uses the engine revolution counter. It does not use the mileage pathway to count down [/qiote]

Edited July 26, 2020 by elcamino