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Check engine light

amillercat2

Full Member
Joined
Apr 20, 2016
Messages
9
2011 LT 4wd 160k miles. I'm a chick that drives a Av and gets taken advantage of when my new best friend, check engine light shows up. I've been chasing my best friend for over a year now and I'm a bit frustrated. I am in need of a solid game plan for troubleshooting purposes to rid my best friend forever.

*The idle has had alittle shudder to it. 3 months ago I had inj/fuel system cleaned, which seemed to help.
*Park Assist shuts itself off (fyi, it won't come back on and I don't care); then Service Stabilitrak light; then the Check Engine Light solid; I fill up tank; 2 days later, Check Engine Light goes out.  And we repeat.
*If low on gas/use Remote Start, the truck will die; when I start, Check Engine Light solid; I fill up tank, 2 days later, Check Engine Light goes out.
*Dec '16, Code P0300/301; replaced coil pack for cylinder 1; replaced wires
*Mar '17, Service 4wheel drive on display, after filling up the truck, at drivethru, tach starts jumping and running rough, put in N, same thing. Limped it home. Next morning, Service Stabilitrak Light, Check Engine Light flashing, Code P0300/307, shifting really hard. Drove to shop. I just had wires installed 3 months ago. I had new plugs put on one year ago. Shop says plugs/wires necessary. Not gapped properly and arching; cleaned MAF sensor.

Something else is clearly wrong here as I've just gone full circle. I can't seem to find an honest tech to help me resolve this issue.
Please help me stop spending money unnecessarily.  Any info greatly appreciated.
 
there's one or two threads here about it, search for those codes on the forum. Multiple misfires could come from a few sources. Check cylinder 7 plug and wire well. Couldn't hurt to check the intake for vacuum leaks either.

If the behavior follows getting gas, has there been any maintenance done to the pump or fuel filter?
 
Thanks for your post Aerohokie.  I will continue my research.  Unfortunately, I have time constraints, I work a full-time job and a part-time job.
They replaced all plugs/wires two days ago.  Truck runs great for the moment.  Its only a matter of time before the misfire shows up and the game begins again.
I was told the fuel filter is inside the sending unit and there is no maintenance required.  True or not?
 
amillercat2 said:
...
I was told the fuel filter is inside the sending unit and there is no maintenance required.  True or not?

TRUE....inside pump inside tank with sending unit attached.
 
Thanks ygmn for your clarification.

I've decided to invest in a BlueDrive OBDII Scanner.  Hopefully this will help.

After researching previous posts, below are potential parts that may/may not help.

Replace L/R upstream O2 sensors, canister, knock sensors, catalytic converters, gas cap, MAF, driver side valve cover, pedal assembly; clean throttle body sensor quarterly

If I were to start replacing parts, what priority would you suggest?
 
We really don't have a lot to go on to make that kind of call. Getting your own scanner is key so you can get all the codes. Multiple misfires vs cylinder 7 are two different things. Did you request your old parts back? If changing out plugs and wires again worked, then something fouled them or it was a part problem.
 
Thanks again. I understand. He did show me spark plug 7 and it was very dark. I did not see the rest of them. Good call on getting the old parts back. I will do that from now on.  I'm pretty excited about that scanner. I should have gotten it a long time ago.

I had an '02 Av with CEL on all the time. Said it was an O2 sensor, just bad gas mileage, not to worry. When CEL was on, it would almost die until the CEL came on again.  I got used to it.

My guess on this truck is O2 sensors and maybe replacing the MAF.  I'm hoping this scanner will provide the root cause so I can fix it before CEL has a chance to show up again.  I do appreciate your time and efforts. There's a good chance I'll be back for additional advice.
 
Black spark plugs, sounds like its running too rich. Could either be the fuel injector staying open too long, or the oxygen sensors causing to dump fuel and run rich. You should see if you can check the fuel trim data with the old reader. Some you can view PIDS and see live data.
 
Chevymike2003 said:
Black spark plugs, sounds like its running too rich. Could either be the fuel injector staying open too long, or the oxygen sensors causing to dump fuel and run rich. You should see if you can check the fuel trim data with the old reader. Some you can view PIDS and see live data.

Yes it does. But she said the injector were cleaned.
 
Have the oxygen sensors ever been replaced?  If not, I would start there since you have 160,000 miles on it.  Could also be a vacuum leak if it's running rich.
 
Have you taken to a good dealership service for their opinion?
 
The O2 sensors have not been replaced.  My understanding is that I have 4 - O2 sensors; 2 in the front and 2 in the back. ?? Which ones would help a rich situation?  I assume replacing the 2 in the front would be most important.  The injectors were cleaned 3 months ago but maybe one is going bad?  I will also suggest checking for a vacuum leak.  My truck has been to 2 different chevy dealerships several times; both cleared the codes, neither was able to explain any root cause; one of which, stole my cell phone car charger when they kept it over the weekend.  There is no such thing as a good dealership, only a good auto tech you can trust.  I do not have that luxury.  I will wait until the scanner I ordered arrives, start testing and proceed accordingly.
 
FYI, if the o2 sensors were bad, they would throw engine codes as well telling you exactly which one is bad.  just letting you know before you start throwing parts at it.  Also sometimes those o2 sensors can be a pain to change if they are fused to their sockets. 

You mention a correlation between empty gas tank and problems...  Try to listen carefully to your fuel pump while in run mode but before starting...  maybe have someone else turn the key to run mode while you are close to the tank.   

When you had your plugs changed 1 year ago, what kind did you get?  I've heard of ppl putting some in that can be problematic... 
Also note that a weak battery/alternator can also cause stumbling and stall issues..  although when thats happened to me, I didn't get any codes...    if thats still the original battery from 2011 then its time to get another.

There's a big thread on service 4x4 problems.  I think this is an isolated separate problem not related to your engine issues. 

 
marzahld said:
FYI, if the o2 sensors were bad, they would throw engine codes as well telling you exactly which one is bad.   just letting you know before you start throwing parts at it.   

O2 sensors get desensitized over time and react slower.  They often don't just "go bad" all at once.  At 160K you shouldn't still be running the originals.
 
UPDATE
This BlueDriver scanner is awesome.
Trouble codes:
C0561 - Anti-Lock Brake System
B2725 - Transfer Case Control Module
Any suggestions or comments? This info will be provided to an auto shop for repairs, if necessary.
 
Now that makes sense, the B2725 means the transfer case encoder motor is receiving a bad signal from the TCCM(transfer case control module).

There are 3 parts to the system, the 4WD switch, the TCCM and the encoder motor.

If he is willing to listen ask him to pull out the plug on the encoder motor and check if there is no water or corrision in it.

Also when the b2725 code comes up it will disable the shifting that could cause a cascade effect and shut down the ABS system.

The C0561 means the ABS module received a bad signal over the network

Disclaimer: No one can tell you for certain what's wrong on the forums because we are not there.

 
 
MS03 - Thanks much for the explanation!  These codes are related then and this is why I get the 'service 4wd' 'service Stabilitrak'.  I will speak with a shop tech and see if I can get some cooperation for a possible solution.  I do understand that no one from the forums can fix my truck.
 
Here is a printout sorry its small, you can down load it and print it.
 

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c05611
 

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PS if you are driving with it in AUTO mode on dry pavement stop it.
 
What part of country do you live in? Not that it really matters too much but if any members are local to you they may offer to help you.

A known fact is that in nearly ALL cases mechanic shops will take advantage of people that don't know about their vehicles. And those shops especially believe women don't know anything. So you should expect that they WILL try to take advantage of you if they think they can. Sad state of affairs but it is more true in some areas than others.

Having said all of that, don't let any shop reset your codes without giving you a printout of the codes. Now that you have a code reader you can do that yourself.

As previously mentioned, only drive in 2wd. ALL GM trucks that are 4wd models are intended to only be driven in anything other than 2wd only on slippery surfaces. AWD vehicles are different. The front wheels turn at the same speed and can't handle turns where one wheel must turn faster than the other with 4wd or auto on.

Some codes will happen due to other issues in your truck. If you have runability problems it is common to have the stabiltrac and traction control systems shut off. ABS normally only shuts off if you have a wheel speed sensor issue or ABS module issue. There are a number of codes like that which are systematic issues instead of individual issues so don't be shocked if you have one code that you get 2-3 others.

A flashing check motor light is a serious issue and generally your truck will switch into limp mode.

There are a number of self serve maintenance items you can do your self. The more you can learn yourself the more you can save in the long term and the less likely you are of a shop taking advantage of you.

Many issues stem from things such as old plugs and wires, dirty air filters and such that you can deal with on your own if your capable. Oil change places LOVE to charge you $15-25 to change your $3 air filter...  Plugs and wires can be bought cheaply online at places like rock auto and are one of the easiest things to do on your truck. It is not uncommon to spent $50 to do a set of plugs and wires if you do it yourself with OEM quality parts but pay a shop over $200 to do the same work. 

If you can get a fuel pressure gauge it can often tell you if you have a fuel system issue. Fuel injectors generally lock open when they need to be replaced which shows up as loosing fuel pressure when your truck is turned off. If your running say 40 PSI of pressure and turn your truck off it should stay steady for a little while. You MAY loose pressure over a period of an hour but certainly shouldn't in a couple minutes. Also a bad fuel pump or plugged strainer will show up as a low pressure issue and never throw a code directly but may show up as an o2 sensor issue or a random/multiple misfire condition. The fuel system has a test valve on it that looks like a air valve on your tire. You hook the fuel pressure gauge to this and check your pressure when running etc. But be aware that they will be pressurized when you pull them off.  Most fuel pressure gauges come with a small length of hose and a pressure release button that allows any pressure to be relieved by pressing the button and some fuel will come out of the tube.

As to your O2 sensors. As previously mentioned they can go bad over time. GENERALLY they only last 100,000 miles, same as plugs but won't throw a code until they get real bad. The front sensors are your actual runability sensors and should be changed more often. The rear sensors only check the condition of your catalytic convertors and should not be changed until they throw a code.  I preach this myself but my '03 has ~270k miles on original O2 sensors as far as I know and runs fine. I REALLY should change those suckers... At this point I will likely wait because I plan to do some serious upgrades if my truck is still in great shape in 5 years and I don't plan to drive it much in the mean time. 

Generally if you can provide your codes on here we can offer our opinions but your best bet is to find a shop that will treat you right and not take advantage of you because your a woman.

Oh and one more thing!

:welcome:
 
MS03 - Thanks so much for all of the info and advice. I feel pretty stupid about the Auto thing. Good grief, Charlie Brown, its in the manual! I really appreciated your directness!  (y)

red - Thanks for the Welcome. I live in Columbus, Ohio. It would be very nice to find a local trustworthy tech. The fuel pressure gauge sounds interesting, as I too believe something is amiss in that area. Thanks for the clarification on the O2 sensors as well. With the exception of the two codes listed, all seems well... so far.

I appreciate the understanding about the 'being a woman' situation. My dad owned a body shop. I spent many summers there. I can mask up and sand anything, but motor stuff, not so much. I guess its time I learn. I'm somewhat capable and can always find a 'how to' on youtube lol Receiving emailed reports from the new scanner is pretty cool. Now to figure out exactly what they mean lol

If you receive legal papers and you don't know all that legal mumbo-jumbo. You pay an attorney to help explain and resolve. You would not be expected to perform legal research on your case and then instruct the attorney on how to do his job. Just saying...

All of you have been plenty helpful and I do appreciate your time assisting me. I love my Av and intend on keeping it since they don't make them anymore. What the hell anyway? I've been driving an Av since '05, now what am I supposed to get? How disappointing.  Thanks again for all the continued support.

I'm a chick that drives a truck, but I don't drive like a chick  :D
 
No problem glad I could help you. it does not matter if you are a lady 98% of guys don't know either.

Gone are the days that you could diagnosis problem with these new vehicles, most shops have not updated their equipment they can do engine work but you have to have a reader that can read the b and c codes and put all the pieces together. Most of them just throw parts at it until it's fixed.
 
MS03 2500 said:
No problem glad I could help you. it does not matter if you are a lady 98% of guys don't know either.

Gone are the days that you could diagnosis problem with these new vehicles, most shops have not updated their equipment they can do engine work but you have to have a reader that can read the b and c codes and put all the pieces together. Most of them just throw parts at it until it's fixed.

Yea its not their vehicle and not their money... So no loss for them and no incentive to really get it right the first time. I started doing my own work after paying over $600 for a bad coil pack. The coil pack WAS bad but the dealer told me that when the coil pack goes out it takes out the main driver board and they have to take the engine apart to get to the coil pack.

My best friends, long ago girlfriends' brother worked at a junk yard and informed me the coil pack cost $30 new at the time and if the other 2 coils were still firing then the brain board was not likely bad since the driver that drove the one coil pack drove all of them. Then he had this "oh yea and the coil pack is bolted to the front of your motor in easy reach..."  SO after paying about 20x more than I should have for an easy job I started learning about fixing my own stuff and learned alot. I am not always right but I do tend to get a lot closer than about 50% of the mechanics I have run into...  Note, the friends ex-gf's bro works at a different junk yard these days and I buy 90% of my parts from him when I need them. Not that it really matters...

Anyhow good luck.

Hope was helpful.

 
The biggest problem with shops and auto technicians is incompetence, NOT dishonesty.  Worked in Dealerships for many years. You would be fired on the spot in any of them for telling a lie to a customer or for trying to do unnecessary repairs.  

For the incompetent technician, if he can't figure out why or what - he typically throws a part at it in desperation and hopes of fixing the problem.  Same with most owners trying to fix their own vehicle.  Think about it.  

So when you happen to find the competent one, treat him well.
 
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