'01 impala engine shuts off / check engine light

I recently found these forums and I reall hope I can get some help here because several dealers are comming up with nothing and telling me I should get the ignition switch replaced on a gut feeling.

The problem: First it started off with the security light comming on while driving. only happened a few times. then the check engine light started comming on while driving. The car would act like it was going to stall the all of a sudden re-enguage for lack of a better work and then the check engine light would come on. Give it a few days ant the light would go off... give it another few days and the same thing would happen again.

Now the problem has morphed to where the engine shuts off while driving and when in park. the a/c and radio will still work just the engine shuts off. put it in neutal and it would start right up... now intermittantly it has a hard time starting.

I am real frustrated with this problem. The deal has been no help. Everytime we take it in they say they can find nothing wrong with the car. This problem sounded simalr to ones posted about a faulty ignition switch whould cause the car not to start but some of my problems sounded different. Please help :)

try to get a new key made (from a gm dealer)

the keys have chips in them, and sometimes htey mess up.

well i am pretty much at my witts end on this problem. GM dealer says its not a clogged cat converter, they have checked the crank sensor and have not gotten it to fail. The service rep says the car has died out twice since they have had it but both times is was when they were moving the car to another bay and they didnt have any test equipment connected to the car. They are wanting me to throw down almost 400 dollars to replace the ignition switch on a technicians "gut" feeling that it is what is causing the problem. I cannot believe with all the equipment they have its comming down to a technicians gut feeling. This is really frustrating..... :banghead:

I'm really starting to learn a lot about the technicians' "gut feelings" lately.

I bought myself an OBD II interface and downloaded the software for it ($75 for the hardware, software free), and now I am learning how the whole system (OBD II) works. As it turns out, there are a few levels of fault codes that the PCM stores, and only sometimes do they light the CEL (check engine light). See this page http://www.autotap.com/articles/OBDII_and_Emissions_Testing.html for an excellent article on how the system works. It's focus is emissions, but it gives much information about the OBD II system in general. Also see here http://www.autotap.com/obdii_library.asp for some informative articles.

Long story short, I would suggest you read up on how the OBD II system works, and go to the dealer armed with this information. Here is a link that talks about the different OBD II modes. http://obddiagnostics.com/

One thing I have realized is that they (dealers) don't BS someone who (they think) knows what the fuck they are talking about. So be that someone who is able to talk their talk and tell them you want them to look at the freeze frame data that the PCM stored before it registered the CEL, and then look at the fuel trim to see if it was trending high or low, then look at the oxygen sensors to see if they are reading that the cat is really doing it's job, etc. Read and learn, and ask questions!

They either don't know how to operate their machine properly, are trying to get you to replace something you don't need replaced, or their $800.00 machine can't do what the $75.00 interface that I bought can do.

I have a 01 had the similar problem. the vehicle has a 3.4 v6. Warmed up my vehicle would run crazy almost die shake sputter then OK?! i checked it out and replaced the fuel pressure regulator. PERFECT! not too bad to do if you have good tools

have they [the dealer] looked for any codes in other modules? from the description of the problem, it does sound like a possible ignition switch [i've seen many], but a lot of times other modules in the car will have a 'U' code [loss of serial data] along with the other symptoms you have, if this is the case it's a good chance the switch is faulty

I love it when people find some info on the internet and they now believe they are self proclaimed experts.
Unfortunately the truth is for most failures, freeze frame/ failure records are usless most of the time. Being able to duplicate the concern and taking a snapshot of what was happening before, during and after the event is a more useful piece of diagnostic information.
The problem with aftermarket code readers and interfaces are they for the most part only read PCM information.
Todays diagnostic strategies and communication protocals rely on cross module communication and most importantly proper power and ground integrity.
Diagnosing an automotive concern isn't as easy as "hooking up the computer and reading codes".
Many faults do not store codes and this makes then even more difficult to diagnose.
An intermitant stalling concern could be caused by a communication failure between 2 modules or something as simple as a bad connection at the battery.
I can tell you that after 22 years working for GM , my "gut feeling" is a much better indicator...especially if I have seen another vehicle with the same symptoms as what you are describing.
Sometimes technology is no match for experiance.

I love it when people find some info on the internet and they now believe they are self proclaimed experts.
Unfortunately the truth is for most failures, freeze frame/ failure records are usless most of the time. Being able to duplicate the concern and taking a snapshot of what was happening before, during and after the event is a more useful piece of diagnostic information.
The problem with aftermarket code readers and interfaces are they for the most part only read PCM information.
Todays diagnostic strategies and communication protocals rely on cross module communication and most importantly proper power and ground integrity.
Diagnosing an automotive concern isn't as easy as "hooking up the computer and reading codes".
Many faults do not store codes and this makes then even more difficult to diagnose.
An intermitant stalling concern could be caused by a communication failure between 2 modules or something as simple as a bad connection at the battery.
I can tell you that after 22 years working for GM , my "gut feeling" is a much better indicator...especially if I have seen another vehicle with the same symptoms as what you are describing.
Sometimes technology is no match for experiance.

That's great! Can I post that at my service desk? If I had a dollar for everytime someone came to me wanting to "hook there car up to the computer" I'd be writing this from my recently purchasd carribean Island!

Chris

have they [the dealer] looked for any codes in other modules? from the description of the problem, it does sound like a possible ignition switch [i've seen many], but a lot of times other modules in the car will have a 'U' code [loss of serial data] along with the other symptoms you have, if this is the case it's a good chance the switch is faulty

well from my experience "u" codes come from the BCM and can only be accessed with a capable scanner like the tech 2 from GM.aftermarket.snapon.matco,and the like to my understanding cant do it no if i'm wrong someone please tell me to shut the f!@k up

well from my experience "u" codes come from the BCM and can only be accessed with a capable scanner like the tech 2 from GM.aftermarket.snapon.matco,and the like to my understanding cant do it no if i'm wrong someone please tell me to shut the f!@k up

Sorry but please check the date and do not resurrect old threads. Thread closed.


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