OBD2 and CEL

[TwiceHorn 31539]

I got a CEL yesterday after stopping someplace in the middle of the day (hottest day of year so far).  I expect that it was hot af under the hood.  Nothing seemed to precipitate it and on the drive home car seemed to be running fine, no excess temperature or anything.

So, I made an appointment at the dealership (has been under warranty until February, so maybe I want to reconsider this).  But on the third restart after its appearance, it is gone.

I have one of those bluetooth OBD2 scanners somewhere that I can't lay hands on and I don't remember if it will display a history of codes if a CEL is not currently on.  I dicked around with it when I got it, but have never actually scanned a CEL with it.

I went to an Autozone and their scanner wouldn't read history either.

Anyway, I guess I should just wait for it to reappear, if it does.  I don't think I want to pay the dealer 100 bucks just to find out that the code was a gas cap (capless) or some shit.  If it's O2 sensors, I might go ahead and have them replaced.  If it's catalytic, I dunno (all assuming that nothing is in failure, but maybe pre-failure).

Should I just ignore and cancel the appointment?  Any other bright ideas?

Edited June 13, 2023 by TwiceHorn

[Prepuce of Doom 21104]

Walking into the dealer and essentially asking them to come up with a problem of their choosing seems like it might be foolish. 

I'd cancel the appointment, then find your code reader and throw it in the glove box so you can read it if/when a CEL happens again. 

[TwiceHorn 31539]

I'd never really considered the ability to read past codes/history.  But it seems like a lot of them don't advertise that ability and that Autozone's wouldn't seemed odd.  I also went to an OReilly's and theirs was busted but he also said he wasn't sure it would show anything if light not on.

I got the reader just to have and was kind of intrigued at having various readouts at my "fingertips."  It was in the glove compartment of my old car and didn't make it into this one and now I have no idea where it went anymore.

I have had only a very few CELs ever, in retrospect.  Like maybe 3?

[TwiceHorn 31539]

38 minutes ago, Prepuce of Doom said:

Walking into the dealer and essentially asking them to come up with a problem of their choosing seems like it might be foolish. 

I'd cancel the appointment, then find your code reader and throw it in the glove box so you can read it if/when a CEL happens again. 

I pretty much trust the dealer, maybe more than I should.

When the warranty expired, I took it in with a couple of suspicions of impending failures (blend door actuators) and they agreed to fix them, and went digging for a couple of other common things and fixed them too.  I was very gruntled by that.

[MonkeyDoughnut 10357]

It's my understanding (albeit limited) that there really is no "history" but pending codes and active codes. These can revert from active to pending to cleared if the problem is determined to have gone away on its own. (manual clearing of codes isn't required). Agree with POD to not worry about it if doesn't show again. 

[Jkwellborn 6747]

Go to a parts house. Most of them will scan it for free. Your car stored the code.

[Mother mopar 3324]

European car?

[TwiceHorn 31539]

11 minutes ago, Mother mopar said:

European car?

Nope, Cadillac.

[Gil Bang 26035]

TWICE IS A FUCKING PIMP!

[Mother mopar 3324]

If you had a CEL and it went away it "latched" to the ECM. You can have it read for peace of mind but if there is no performance degradation and all operating parameters are normal I would press on with life.

Could of been a glitch in communication between circuits or a sensor got wet, bad ground who knows. Modern cars are really finicky like that.

[TwiceHorn 31539]

6 hours ago, Mother mopar said:

If you had a CEL and it went away it "latched" to the ECM. You can have it read for peace of mind but if there is no performance degradation and all operating parameters are normal I would press on with life.

Could of been a glitch in communication between circuits or a sensor got wet, bad ground who knows. Modern cars are really finicky like that.

Yeah, I'm just curious.  But not so curious that I'm going to pay the dealer for an engine diagnostic and let them run wild on a repair bill.

I suspect it's something emissions related.  Maybe even as simple as the gas cap problem on a leaky capless gas filler on a really hot day.

I was very surprised that Autozone claimed not to be able to read a "non-current" code, and O'Reilly said essentially the same thing.  So I began to wonder about about the capabilities of cheap OBD scanners, and OBD itself.  Sometimes those old electronics standards are kind of weird in terms of not doing what you think they'd do based on current tech.

Edited June 13, 2023 by TwiceHorn

[TwiceHorn 31539]

6 hours ago, Gil Bang said:

TWICE IS A FUCKING PIMP!

My second one, actually.  Great driver's cars.  First one was incredibly trouble free.  This one has been less so, possibly bordering on biggest POS I've ever owned under warranty so far, but godalmighty it is fun to drive.  I'm paranoid.

[Jkwellborn 6747]

Yeah, I'm just curious.  But not so curious that I'm going to pay the dealer for an engine diagnostic and let them run wild on a repair bill.
I suspect it's something emissions related.  Maybe even as simple as the gas cap problem on a leaky capless gas filler on a really hot day.
I was very surprised that Autozone claimed not to be able to read a "non-current" code, and O'Reilly said essentially the same thing.  So I began to wonder about about the capabilities of cheap OBD scanners, and OBD itself.  Sometimes those old electronics standards are kind of weird in terms of not doing what you think they'd do based on current tech.

Unless something’s changed, the vehicle will store the code until it’s erased.

[fattyflattie 4638]

1 hour ago, Jkwellborn said:

Unless something’s changed, the vehicle will store the code until it’s erased.

Yep. I have a “cheap” (~150$) OBD2 reader and it’ll dig up old codes, until they are erased of course.  It is GM specific but reads and does shitloads of diagnostics on everything from the yukon we keep on the ranch to my Dmax.   It’s been pretty damn handy thru the years. 

[locodos 5396]

or you can just slum it and go to Autozone where they'll read the codes for free...   even tell you what's wrong.

https://www.autozone.com/diy/maintenance/top-five-reasons-check-engine-light#:~:text=AutoZone gives you a FREE,that needs to be taken.

Quote

THE AUTOZONE FIX FINDER
Fix Finder is an easy-to-use tool to troubleshoot why your Check Engine Light is on using an extensive database of repair solutions from ASE-certified mechanics to help you find the most likely fix.

HOW DOES AUTOZONE FIX FINDER WORK?
Fix Finder reads diagnostic trouble codes from your vehicle’s onboard diagnostic system, and pulls your vehicle information and mileage.
This data is analyzed to give you vehicle-specific fix solutions that have been verified from the records of over 5.5 million ASE-Certified technicians.
AutoZone gives you a FREE, easy-to-read MYZONE HEALTH REPORT, which includes relevant codes, and details the action that needs to be taken.
LET US HELP YOU FIND OUT IF THE PROBLEM IS SIMPLE OR SERIOUS
Your Check Engine Light may indicate a simple problem that’s easy to fix—such as a loose gas cap that needs to be replaced. It could also be a warning of a serious problem that could damage your engine components.

Your Check Engine Light blinks or glows depending on what’s wrong with your vehicle. A flashing Check Engine Light indicates that your vehicle’s engine is in serious trouble, whereas a steadily lit one means less urgent service is needed. Regardless, it’s easy to find out what the issue, and taking care of it quickly can save you money and prevent further damage down the road.

 

check that your gas cap is on tight.  It can throw a code.

Edited June 13, 2023 by locodos

[TwiceHorn 31539]

13 minutes ago, locodos said:

or you can just slum it and go to Autozone where they'll read the codes for free...   even tell you what's wrong.

https://www.autozone.com/diy/maintenance/top-five-reasons-check-engine-light#:~:text=AutoZone gives you a FREE,that needs to be taken.

 

check that your gas cap is on tight.  It can throw a code.

It's capless, would not be surprised if it leaked a little.

The Autozone guy said if the CEL wasn't on it wouldn't read a code.  Guess it varies with whatever reader they've got.

Since I was asking for free shit, with almost zero likelihood that I would buy anything and fix it myself, I didn't feel like pressing the issue.

Edited June 13, 2023 by TwiceHorn

[Native Horn 3516]

12 hours ago, TwiceHorn said:

Nope, Cadillac.

It's all good, man!

[Mother mopar 3324]

Yeah, I'm just curious.  But not so curious that I'm going to pay the dealer for an engine diagnostic and let them run wild on a repair bill.
I suspect it's something emissions related.  Maybe even as simple as the gas cap problem on a leaky capless gas filler on a really hot day.
I was very surprised that Autozone claimed not to be able to read a "non-current" code, and O'Reilly said essentially the same thing.  So I began to wonder about about the capabilities of cheap OBD scanners, and OBD itself.  Sometimes those old electronics standards are kind of weird in terms of not doing what you think they'd do based on current tech.

Agree, because dealerships will upsell you on some BS that you don't need or could do yourself.

Some manufacturers have limits on what an OTC scanner can see or do within their ECM/PCM. Unless you have a snap-on solus (or similar with OE "keys" then you can retrieve the code. If it's a gas cap slap some Vaseline on that thing and she'll be good. Spit will work short term (that's what she said).

[shakahorn 1645]

3 hours ago, Mother mopar said:

Agree, because dealerships will upsell you on some BS that you don't need or could do yourself.

Some manufacturers have limits on what an OTC scanner can see or do within their ECM/PCM. Unless you have a snap-on solus (or similar with OE "keys" then you can retrieve the code. If it's a gas cap slap some Vaseline on that thing and she'll be good. Spit will work short term (that's what she said).

username checks out.

[Braff Zacklin 13665]

10 hours ago, TwiceHorn said:

My second one, actually.  Great driver's cars.  First one was incredibly trouble free.  This one has been less so, possibly bordering on biggest POS I've ever owned under warranty so far, but godalmighty it is fun to drive.  I'm paranoid.

Hate to break it to you, 2x, but the second Caddy is probably a lemon.

However, because we're great friends and I'm such a swell guy, I'll take it off your hands. Just drive it on up to Idaho. I'll even buy you a burger for your trouble.

You're on your own getting back home, though.

[TwiceHorn 31539]

Ok it happened again today, under similar conditions:  blazing hot, 104 by the dash thermo, moderate on-ramp acceleration.  It also went away on the third engine restart.  And ran smooth and strong in the meantime.

But, in the interim, stopped at an O'Reillys and got the code, P1101, so MAF testing out of range.  So, a $100 part and a DIY repair if it becomes less intermittent.  

So, I guess if anyone wants to tell me about their engine grenading from an intermittent MAF failure, now is the time.

Edited July 15, 2023 by TwiceHorn

[nobody 1]

I would try cleaning the wire on the MAF sensor first.  

[fattyflattie 4638]

3 hours ago, TwiceHorn said:

So, I guess if anyone wants to tell me about their engine grenading from an intermittent MAF failure, now is the time.

Shouldn’t be anything to worry at all. Worse economy when it’s acting up, if you run it that way for long periods it can do funky things when running lean/heavy.  

[Nice Guy Eddie 13523]

Dumb question but why do modern vehicles with digital panels still require an device to interpret the engine codes? I can understand still have the external port in case the digital panel is out but the process seems like a method to ensure dealership service $.

[MonkeyDoughnut 10357]

2 hours ago, Nice Guy Eddie said:

Dumb question but why do modern vehicles with digital panels still require an device to interpret the engine codes? I can understand still have the external port in case the digital panel is out but the process seems like a method to ensure dealership service $.

More of a federal standard so everything can be read same way so easier to diagnose across all vehicles. Last thing we need is some mechanic scrolling 50 screens with their grubby hands.

[Jkwellborn 6747]

Dumb question but why do modern vehicles with digital panels still require an device to interpret the engine codes? I can understand still have the external port in case the digital panel is out but the process seems like a method to ensure dealership service $.

The government standardized them in the late 80s or early 90s. Until then it was OB1 and most manufacturers used different ports.

[Braff Zacklin 13665]

On 7/15/2023 at 3:09 PM, TwiceHorn said:

Ok it happened again today, under similar conditions:  blazing hot, 104 by the dash thermo, moderate on-ramp acceleration.  It also went away on the third engine restart.  And ran smooth and strong in the meantime.

But, in the interim, stopped at an O'Reillys and got the code, P1101, so MAF testing out of range.  So, a $100 part and a DIY repair if it becomes less intermittent.  

So, I guess if anyone wants to tell me about their engine grenading from an intermittent MAF failure, now is the time.

My offer stands.

(It's a good burger.)

[TwiceHorn 31539]

On 7/15/2023 at 6:33 PM, nobody said:

I would try cleaning the wire on the MAF sensor first.  

Haha, so it happened a third time, blazing hot, hard acceleration short of WOT.  

So, for shits n giggles, I decided to try this.  I was also advised to check my air filter and possibly clean the throttle body.

So, I slide out the MAF and hose it down and put it aside to dry.  It was, externally at least, clean as a whistle.

This MAF sensor is woke.

And I begin to unscrew the air filter canister.  For whatever reason, the screws on that canister were really hard to turn and there are five of them, so my hand was pretty tired after all that.  Air filter was ok, not great but not filthy either.

So, I go back to inserting the MAF and secure one screw.  I carefully started the other screw and inserted my torx driver and began to turn.  It felt a little stiff so I backed it out and was going to rethread it and donk, the screw drops into the bowels of the front end.  And there is a shitload of stuff in the front end, including a "fairing" at the bottom, so no it doesn't fucking drop to the driveway.

Fuck. Me. In. The. Goat. Ass. 

So I quit screwing with it last night,  This morning, I get up grumbling and go out there and sure as fuck, I spy the screw sitting an an A-arm or something similar, but I can't reach it.  At one time, I had a magnet stick but I don't know where it is anymore.   

So, more grumbling.  Then I put a wad of chewing gum on a straw and GOT THAT LIL MOTHERFUCKER.

Put everything back together and also hose down the connectors with MAF fluid.  I let them dry, but probably not enough.  Hooked it up and started the engine.

CEL.

But, it went away after the fourth or fifth restart today, so I'm thinking the connectors were still a little damp.

That whole misadventure deterred me even more from attempting to clean the throttle body or disassemble the intake duct   In addition to not having a lot of the right tools to do car work anymore, I lack a bunch of metric torx head machine screws. So, fuck all that.

I have been clued in on how to tell if an intake leak is happening, and maybe even to locate it, but it requires a fairly heavy-duty OBD scanner.  The one I had might do that stuff, or not, but I can't find it atm, and that makes me not want to buy another one, particularly a fairly spendy one.

Trying to shade tree mechanic a modern vehicle is a pain in the ass.

 

Edited August 15, 2023 by TwiceHorn

[fattyflattie 4638]

1 hour ago, TwiceHorn said:

It felt a little stiff so I backed it out and was going to rethread it and donk, the screw drops into the bowels of the front end.  And there is a shitload of stuff in the front end, including a "fairing" at the bottom, so no it doesn't fucking drop to the driveway.

Fuck. Me. In. The. Goat. Ass. 

So I quit screwing with it last night,  This morning, I get up grumbling and go out there and sure as fuck, I spy the screw sitting an an A-arm or something similar, but I can't reach it.  At one time, I had a magnet stick but I don't know where it is anymore.   

I’ve been dropping bolts like crazy over last few weeks (diesel thread for full list of work) on the dozen or so parts I’ve freshened up lately.  Saw a YouTube short trick the other day.  Put a few magnets in the fingers of a nitrile glove, put glove on, find bolts easily.   In my experience it’s been way better success ratio that using the stick (blindly) 

[TwiceHorn 31539]

2 hours ago, fattyflattie said:

I’ve been dropping bolts like crazy over last few weeks (diesel thread for full list of work) on the dozen or so parts I’ve freshened up lately.  Saw a YouTube short trick the other day.  Put a few magnets in the fingers of a nitrile glove, put glove on, find bolts easily.   In my experience it’s been way better success ratio that using the stick (blindly) 

So, just grope around and stuff sticks?  Interdasting.  Not sure that would have helped this situation because it was one of those where if I could get any appendage on it, it would have been one finger, maybe two at the outside, but I couldn't have gripped it and extracted my hand.  I have a round magnet with hole in it somewhere that I thought about putting on a string, but I think it would have stuck to everything but the screw and I'd have had a really hard time getting it down to the screw.  I kind of foresaw similar problems with the magnet stick, had I been able to locate it.

I was so damn careful with those MAF screws when they were out, putting them in a little tray, and same with the air filter screws.  And then I got a little careless screwing it in.  Probably wouldn't have made much difference with one screw missing, but I have become paranoid about things in and around the intake duct leaking, which might be the source of this problem when intake pressure gets high, or low, as it were.

 

[fattyflattie 4638]

1 hour ago, TwiceHorn said:

So, just grope around and stuff sticks?  Interdasting.  Not sure that would have helped this situation because it was one of those where if I could get any appendage on it, it would have been one finger, maybe two at the outside, but I couldn't have gripped it and extracted my hand.  I have a round magnet with hole in it somewhere that I thought about putting on a string, but I think it would have stuck to everything but the screw and I'd have had a really hard time getting it down to the screw.  I kind of foresaw similar problems with the magnet stick, had I been able to locate it.

I was so damn careful with those MAF screws when they were out, putting them in a little tray, and same with the air filter screws.  And then I got a little careless screwing it in.  Probably wouldn't have made much difference with one screw missing, but I have become paranoid about things in and around the intake duct leaking, which might be the source of this problem when intake pressure gets high, or low, as it were.

 

May not have worked, but has been working magic for me with my newfound butterfingers.   Then again, I'm always working on a truck/SUV with decent room to get your hands in and about.   I still use my magnet stick or the grabber if I can see it and it's in a tight spot.  

[Jkwellborn 6747]

Magnetic screwdrivers and having an extendable magnet work wonders for those things.

If you’re looking for an intake leak, you can crank the vehicle and start spraying break cleaner around it. Makes it run different.

You could blow smoke around it too.

[TwiceHorn 31539]

My first car and thus the first car that I paid a great deal of attention to mechanically was a 1969 Olds Delta 88.  Even though it had a 455, you could almost climb into the engine compartment with it to work on it.

There's just a staggering amount of stuff under the hood anymore.  I can still point out the function of just about everything there, but man it's a hassle to get to things and all the plastic they put in there to sort of dress things up is kind of irritating.  And now you add in a turbocharger and it's just that much more stuff crammed in there.

My last few cars have had a good bit of warranty when I bought them and were quite trouble free post-warranty, so I have never bothered finding a good non-dealer mechanic.  They were also NA, so comparatively less complex.  I bought the OBD for a Cadillac CTS and it never threw a CEL in 90,000 miles, except when the water pump sprung a leak, and I didn't need an ODB scanner to figure that one out.  And that explains why I have misplaced the thing, I never needed it.

But all cars now seem to be approaching the level of complexity of a BMW or Benz or something and you kind of feel like you need a "special" mechanic to work on them. 

But I guess even Joe Bob's Garage has to be fairly up to speed with all the little weirdnesses of modern vehicles.