# Unknown CEL



## Tomko (Jun 1, 2013)

Just a SWAG - but are you still running on the original battery?


----------



## MP81 (Jul 20, 2015)

Yeah, original battery with the negative cable TSB taken care of.


----------



## diesel (Jun 8, 2013)

I've had issues with various code readers. The ones at the auto parts stores always seem to work. Might be worth swinging by and having them pull your codes. The ones around here do that for free.


----------



## MP81 (Jul 20, 2015)

Yeah, ours are free too. Usually the code is gone by then, though it should be stored.

Car has to go to the dealer anyway ("Service Side Detection" as of yesterday), maybe they can pull it while it's there.


----------



## PanJet (Jun 18, 2013)

The only two CELs I have had so far are the O2 sensor (sooted up) and the #2 EGT. Neither presented any drivability or running symptoms whatsoever. The #2 EGT actually went away on its own before it came back.


----------



## Tomko (Jun 1, 2013)

Is your car clean? I wonder if there's any mud or ice that's interfering with the sensor?


----------



## MP81 (Jul 20, 2015)

Just dirty from some salt on there - but we've gotten rain as of late, so it's more just "on there" now. No ice or mud or anything like that. 

It might be unrelated, but thinking about it now, maybe in the past week or so (before the code went off), there were a couple false alarms on one of the sides when backing out of the driveway, and clearly nothing was there. Probably related...


----------



## diesel (Jun 8, 2013)

Good luck and keep us posted!


----------



## MP81 (Jul 20, 2015)

Will do. 

Swapping cars with my wife here at work today (she gets to drive the RaceCav home, lucky her. Poor girl can barely see over the dash with the 4th Gen Camaro seats in there, haha), swinging by WalMart to grab some of their DEF ($7 for 2.5 gal, and it's API-certified, so good to go) since she got the warning for speed limitation due to low DEF (soon, I'm guessing, because she was doing 75-80 on the freeway with that message). Filling that up (at least one of the containers), then dropping the car off at the dealer. 

I'm wondering if the sensor issue is causing interference with the key fobs or something strange. Guess we'll see.

Car is over 36k miles, so I'm hoping I don't have to pay a fortune for **** that shouldn't be broken anyway...


----------



## boraz (Aug 29, 2013)

i know with big trucks, we would get codes active and non active, but the non actives would still read on the laptop...

does your scanner show inactive codes?


----------



## MP81 (Jul 20, 2015)

Not that I know of - it's only a cheap scanner. I'd bet if it were a Tech 2 clone or something similar it would.

So an update thus far: CEL hasn't made a return yet, but did some investigation of my own before throwing in 2.5 gallons of DEF mostly in the tank (yeah, I spilled a little...but not a ton...glad there were about 45 napkins handy in the trunk to clean up the 1/8 cup or so of Urea, whoops...) with the key fob.

It has to do with the LEDs...but *only* if the Dome Lights are left to entry mode (turning on when the door is opened, and off when the close). If I turn the dome lights to off *or* fully on, it's fine...I sat in the car with the entry mode on, and as soon as the dome light dimmed and turned off, I was able to do the second press easily. Very strange - but definitely not the car's fault - some weird interference from the LEDs in only one mode though...thoughts?

Having driven the car since my wife mentioned the issue with the "side detection", I can see what she said - it's sporadic, and will usually notify you multiple times during a drive - though I had one drive where it didn't tell me at all.

Dropped it off at the dealer for that and the oil change (since I "figured out" the root of the key fob, I told them not to bother with it, as I don't believe it to be a vehicle fault - rather, a strange occurrence related to LED lighting that we can maybe live with), and our dealer was great as usual. Even though we passed the warranty period for bumper to bumper by less than 1000 miles, they're going to cover it under warranty and gave my wife a 2016 Traverse as a loaner. Great group of people there. 

Assuming the get an idea what the **** is going on with the sensors, I'll update the thread. As far as the CEL goes, well..I forgot to ask..haha. They're doing their normal 27-point inspection, so maybe they'll read stored codes (I did tell them up front I know the fuel filter is at 2%, and I have a new one to install).


----------



## MP81 (Jul 20, 2015)

Picked the car up yesterday - dealer said one of the sensors had gone bad and was causing the error, so they replaced it. Oil change is completed as well.

However, my wife says she still gets the side detection message...is that something they forgot to clear, or is it still bad? Might have her stop back by and have them take a look next week. Not that it's needed, but it's just one more annoying message to have to cancel on the drive down to NC next weekend.


----------



## IndyDiesel (May 24, 2015)

MP81 said:


> Picked the car up yesterday - dealer said one of the sensors had gone bad and was causing the error, so they replaced it. Oil change is completed as well.
> 
> However, my wife says she still gets the side detection message...is that something they forgot to clear, or is it still bad? Might have her stop back by and have them take a look next week. Not that it's needed, but it's just one more annoying message to have to cancel on the drive down to NC next weekend.


When you say a side detection message, does your Cruze have blind spot monitor? Not sure I understand what you mean?


----------



## MP81 (Jul 20, 2015)

Yeah, we have the safety package. Rear sensors work when backing up, but it's speaking of the blind spot monitors - it refers to them as "Side Detection" on the DIC.


----------



## diesel (Jun 8, 2013)

MP81 said:


> Picked the car up yesterday - dealer said one of the sensors had gone bad and was causing the error, so they replaced it. Oil change is completed as well.
> 
> However, my wife says she still gets the side detection message...is that something they forgot to clear, or is it still bad? Might have her stop back by and have them take a look next week. Not that it's needed, but it's just one more annoying message to have to cancel on the drive down to NC next weekend.


She should not be getting the message if they fixed it properly. Most likely there's still a problem somewhere.


----------



## MP81 (Jul 20, 2015)

That is my thought. The lights on the mirrors come on at startup, but it says there is an issue. Since it's a repair, she can probably bring it back in and have them look at it. Maybe they just forgot to plug the sensor in. Any idea where the side detection sensors are? I might be able to take a look when I'm under the car doing the fuel filter tomorrow.


----------



## oilburner (Jun 13, 2013)

MP81 said:


> That is my thought. The lights on the mirrors come on at startup, but it says there is an issue. Since it's a repair, she can probably bring it back in and have them look at it. Maybe they just forgot to plug the sensor in. Any idea where the side detection sensors are? I might be able to take a look when I'm under the car doing the fuel filter tomorrow.


their all in the rear bumper.


----------



## MP81 (Jul 20, 2015)

Okay, that's what I thought.

My wife got the car washed yesterday morning, and upon taking a trip over to the mall around lunch time - the sensors worked just fine. 

On the drive home - nope, stopped working again. Weird as ****.


----------



## ChevyGuy (Dec 13, 2014)

MP81 said:


> It has to do with the LEDs...but *only* if the Dome Lights are left to entry mode (turning on when the door is opened, and off when the close). If I turn the dome lights to off *or* fully on, it's fine...I sat in the car with the entry mode on, and as soon as the dome light dimmed and turned off, I was able to do the second press easily. Very strange - but definitely not the car's fault - some weird interference from the LEDs in only one mode though...thoughts?


I'm not sure what problem you're referring to here. But if you've got LEDs in the front dome light, it might be causing interference with the fob receiver which is only a few inches away. But only when the LED is lit.




MP81 said:


> My wife got the car washed yesterday morning, and upon taking a trip over to the mall around lunch time - the sensors worked just fine.
> 
> On the drive home - nope, stopped working again. Weird as ****.


The side sensors are in the bumper area - right where the rear tires would throw all kind of crud. If they're not perfectly weather proof ..... I just hope you took it into the dealer for that before you went over 36,000 miles.


----------



## MP81 (Jul 20, 2015)

ChevyGuy said:


> I'm not sure what problem you're referring to here. But if you've got LEDs in the front dome light, it might be causing interference with the fob receiver which is only a few inches away. But only when the LED is lit.


It won't knowledge the second press (whether locking or unlocking) for a few seconds after the first press. If I set all the interior lights (so both domes, and the map lights) to on, it has no issues, all off, fob works fine. Only when I have them set to entry does it cause an issue. This is why I'm confused by why it'll only do it in that mode.



ChevyGuy said:


> The side sensors are in the bumper area - right where the rear tires would throw all kind of crud. If they're not perfectly weather proof ..... I just hope you took it into the dealer for that before you went over 36,000 miles.


Dealer was great and covered it under warranty. Checked their notes and they cleared the code and test drove it after replacing the sensor. It just needs to not still be an issue, haha.


----------



## ChevyGuy (Dec 13, 2014)

MP81 said:


> It won't knowledge the second press (whether locking or unlocking) for a few seconds after the first press. If I set all the interior lights (so both domes, and the map lights) to on, it has no issues, all off, fob works fine. Only when I have them set to entry does it cause an issue. This is why I'm confused by why it'll only do it in that mode.


Do the interior lights come on with the first press? If so, then I could see the interference blocking the second press. 

The only thing I can think of being different for entry is that the BCM does a PWM signal to the dome light so it can fade up/dim out. If you set it to manually on, it may not do PWM at all. The BCM's PWM combined with what the LED may be doing might be creating the interference on just the wrong frequency.

Great detective work, by the way.


----------



## MP81 (Jul 20, 2015)

Yeah, when you unlock, they come on, and you can't get the second press. And they stay on for a little bit before fading when you lock it. Sat in the car and locked it and it was exactly when the light faded was when I was able to get the second press to take. 

I'm definitely thinking it's something along those lines...something with the fade and the LED...

And thanks - it's a real strange problem, and can't say I see any examples of the same issue. Just puzzles me. It's annoying, but I'd rather have the LEDs than immediately be able to have that second press work. But if I could solve it - even better.


----------



## ChevyGuy (Dec 13, 2014)

Try a different brand of LED. Or you could even try swapping the LED from another location into the dome light. It might be just enough of a change to throw the interference to a different frequency.


----------



## MP81 (Jul 20, 2015)

I was thinking of something similar to your idea of switching them. All the LEDs inside the car are the same type (SuperbrightLED 5-LED towers), so that won't be too bad to swap around and test.

The first test will be removing one or the other and seeing which has an effect on the remote.


----------

