Last post on Nov 25, 2013 at 5:21 PM
You are in the Chevrolet Colorado and GMC Canyon
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Chevrolet Colorado, GMC Canyon, Electrical, Truck
#633 of 684 Re: 2005 Chevy Colorado Ignition Problems, Windows & Locks problems and more... [snaproll1]
Feb 16, 2012 (4:35 pm)
Yes, snaproll1, you are somewhat correct in that there is an area in vehicle computers that is called "volatile ram". This area stores the engine or body code used to help troubleshoot problems. This area is also used to store data used in "learning curves" for engines especially. For instance, the engine computer stores data it uses to know how much "fuel trim" is needed for a particular vehicle. It learns this by recording how much extra (or less), fuel is needed beyond the programming amount to make the exhaust exactly 14.7 to 1 oxygen to fuel mixture. Transmission computers use this area also to learn smooth shift patterns in much the same way.
Before 1996 (OBDII), when someone disconnected the battery. The codes and the small amount of learning data were lost. A few drives and restarts re-established the learning curves. Now with OBDII and beyond, the technician has to use a reader to clear and remove learning curves (fuel trim, shift data, etc), from the ECM or Body computer. Usually by clearing the codes by a reader it also flushes the learned data also. We always caution the customer that your vehicle may perform slightly different for a couple hours or less after clearing codes. Most are unable to notice a difference though.
Every time you turn off your vehicle (as of yet), the computers shut down except for this small kept alive memory. When you turn the key back on, the computers have to initalize and start reading the burned in instructions to execute from ROM. Therefore, (as of now), it would be virtually impossible to execute wrong code including a virus or for the existing computer instructions to get corrupted. Remember, the instructions are contained in ROM or "Read Only Memory". Yes the computers look at the RAM area for data that is contained there but no computer instructions are in this area.
With PC's and Laptops, this is a totally different story. When you turn your computer on, the first thing the processor does is to read BIOS for the instructions to access the hard drive. Once it starts reading the hard drive, it is picking up computer instructions on how to execute Win98, WinXP, Win7, or a host of other operating systems that you as a user can install on the hard drive. This is where a VIRUS loves to be. Malicious code can be written to a hard drive that replicates itself on CDROMS, FLOPPY drives, Memory sticks, Internet programs, and etc. This code can be carried to other computers and cause the new computer to write these instructions on it's hard drive and continually replicate itself to other computers.
Yes, a trained technician can FLASH a new ROM onto a vehicle engine computer or body computer. However, this is only allowed if there is an UPDATE available from the manufacturer and it takes special tools and usually a $1800 a year fee to do these operations. So dealerships are usually the only ones that are able to do this. There are also safeguards when programming that checks the "Checksum" at the end of programming to see if the code installed matches exactly; otherwise a message pops up that says "Programming Unsucessful".
When I had my window/lock problem, all the other functions on the body computer for my Colorado worked perfectly. The radio would turn off when the doors were opened. The dome light would go off at night when the key was inserted, and all the seatbelts, low fuel, alarms, and etc worked flawlessly. The only thing that didn't was the drivers door window, and the locks. The parking lights would flash with the fob but no lock activation occured. This told me that the body computer was acting normally and was intact. Yes Murphy's law is still possible. The body computer could get corrupted. But simply a turn off of the vehicle and a restart would re-initalize the computer sequences and would be ok again. If you noticed, quite a few people tried disconnecting the batteries and etc and it didn't fix the problem. Some said it did and others said it did not help.
With all this said, I am only human and maybe someone can show me that I am all wrong. If so, I am happy with that also.
Catch you later, Dennis
#634 of 684 Re: 2005 Chevy Colorado Ignition Problems, Windows & Locks problems and more... [snaproll1]
Feb 16, 2012 (7:35 pm)
Thanks for the reply Dennis. I'm still thinking there has to be some kind of "programming flaw", the old "garbage in garbage out" scenario.
Again, I have no idea how 'code' is derived in vehicles but I do know a bit about computers and coding itself. You're making the assumption that the ROM code is "flawless". I have seen really weird things happen with low level code, "programming errors" that are so subtle they are nearly impossible to find. They are nearly impossible to reproduce because the confluence of circustances that cause them are so obscure. It might be an obscure piece of code that runs but whoever coded used a case statement that doesn't address that particular condition, or there is a missing return or something, no error handling and the code thread falls through executing some other instructions out of sequence that screws up something else, which in turn screws something else up until the BCM is hozed. Maybe when the ROM was being written somebody coded an incorrect label and the code thread shifts to some nonreadable data area and the BCM is hozed.
Right from the get-go these trucks had weird electrical issues. Here's an example, I've heard similar storied from a couple of other owners... When I got the truck I wanted to make sure the door key worked. I tried it in the lock and the horn started to 'toot' lightly as the door unlocked. A few seconds later it started the "somebody is stealing me!" scream. I hit the panic button and it stopped. Kind of shaking my head I looked at the GM sales reps, and asked what the truck was doing. Sheepishly they just kind of shrugged like, "Ummmm, that's the new... ahhh, horn-test system I guess?" They had no clue, we kind of figured it was some kind of "new thing" that would be explained in the manual. Of course there was nothing, so maybe it was something "undocumented"? Perhaps, but my guess is it was the first sign of some weird programming error.
The more I think about it, the more I have to think the majority of these problems have to be computer and/or code ("programming code") related. The reason I think this is because some of the weird electrical stuff would be hard to explain if it was simply 'physical' problems like frayed or shorted wires. Things like that don't usually "get better" or heal themselves, but computers can and do. With a computer a weird set of circumstances and poorly written code can can screw them up and likewise a weird set of circumstances (disconnecting battery leads, putting the key in the ignition at the right time, turning on the lights, some kind of sequence of inputs) can heal (reinitialize/clear) them.
How else can some of the weird stuff be explained like turning on the radio locks the doors or whatever. I guess it could be physical like shorted wiring, but it sure as heck sounds like poorly written process control code.
Again, I'll be the first to say I may be completely off base and this stuff and what I say is impossible, but for a moment let's say it is possible... Say some highschool dropout at GM was writing the BCM control code and was still stoned from lunch and kind of forgot a return instruction before sending the code off to be burned as ROM into 16 million BCMs. Everything looks ok and the problem doesn't get discovered until that particular piece of code gets executed, something like, the lights have to be off, the radio on and the air conditioning on when the truck is turned off and the key left in the ignition with the dome light left on for over 20 minutes. Maybe that piece of code gets executed when the BCM realizes the dome light is still on and the code is supposed to turn it off. It does, but rather than return to wherever it is supposed to go, the thread falls through into "the twilight zone". Somewhere along the way it turns power into the drivers window relay and shorts out the little chip in the drivers window/fob circuit. This causes the battery to drain and with the low voltage fries something else when the key is put back in the ignition and the BCM fully powers up. Like I say, just some weird confluence of circumstances that happens every 6 weeks to 6 years. In the mean time, add in the poor grounds and wiring connectors and... you have a nightmare to solve.
Let's say that scenario has even a grain of truth. What is the "proper fix"? Troubleshoot and locate the obscure problem in the code, do all the testing and debugging, then what? Produce new BCMs with the corrected ROM code? Recall all the existing BCMs in all the trucks? And if the code is written so crappy in one place, what's not to say there may be other code glitches that haven't been found and would be burned into the new BCM ROM anyway? For so relatively few customers? (The Colorados/Canyons were not big sellers). Factor in a company going bankrupt on top of this, would you elect to have a recall? Incurr all this expense? Forget it, just donate to Obama and get tax money to stay in business instead of relying on satisfied customers. We're back in business again, just sweep the Colorados under the rug except for the lucrative repair money... The guy that programmed the Colorado BCM was probably promoted to doing the electrical system on the Volt...
Anyway, that's my rambling thoughts. I guess it really doesn't matter since GM is obviously not going to address the reoccuring problem that doesn't exist. It really would be interesting if there ever was a definitive answer but I doubt it will ever be determined for sure.
#635 of 684 Re: 2005 Chevy Colorado Ignition Problems, Windows & Locks problems and more... [den052]
Feb 19, 2012 (6:10 am)
Just a little FYI for all you Colorado/Canyon owners...
Because of the Japan tsanami wiping out the competition, GM actually make a 7 billion profit.
Of course the auto supply chain from Japan is back online now and next year projections for GM next year are grim. Their stock is still in the tank after you and I bought the company for Obama but does this concern them? No.
While times are good and they have this windfall of money, do you think they might consider paying off their government loans? (Eh-eh, are you high?). Do they try to fix the electrical system on the Colorado? (You really are stoned if you might think so, why kills such a great repair cash cow).
No.... they decide to give all their union employees a $7,000 bonus! (Way to go Peggy, spend my tax money well).
#636 of 684 Re: 2005 Chevy Colorado Ignition Problems, Windows & Locks problems and mor [den0520218]
Feb 22, 2012 (10:13 am)
Well, this didn't fix my problem. But I guess it didn't hurt trying. Hate the thought of trying to take it somewhere, but I may have to. Thank you for your suggestions!
#637 of 684 Re: 2005 Chevy Colorado Ignition Problems, Windows & Locks problems and more... [snaproll1]
Feb 22, 2012 (5:16 pm)
Snaproll1: An interesting thing happened with a 2005 Ford E350 I was working on. I was servicing the batteries and connections because of a P0611 code: "FICM voltage problem or Fuel Injector Control Module voltage incorrect". This was on a 6.0l diesel. Tested the FICM and voltages were correct. There was a TSB out for re-flashing the FICM for random generation of the P0611 code without voltage problems. The customer was also complaining of batteries running down after a few days so I did a "parasitic battery draw" test. I removed the negative chassis ground and inserted a DVM measuring millivolts. I was testing how much draw on the batteries with everything turned off. As a general rule vehicle computers always draw a few milliamps of power for memory retention.
I measured the draw at 65ma which is ok- anything under 100ma is good. However upon making and breaking the system ground, the power door locks turned on and activated a couple times during interruption of current flow.
When I went to open the doors on the vehicle, they were locked and the keys were inside. Thankfully, the drivers window was wide open. That is one thing I generally do when working on a vehicle is roll the drivers window down. I just got in the habit of doing it over the years and good thing I did.
The interesting thing is that the computer system called for the locks to activate when the computer system was unstable. Upon shutting off the vehicle and restarting it, things turned back to normal.
So, end result is that you and I are both right. A glitch can screw up a body computer and re-initalizing the computer straightens it out (at least untill it screws up again). LOL LOL LOL
#638 of 684 Re: 2005 Chevy Colorado Ignition Problems, Windows & Locks problems and mor [luciro]
Feb 22, 2012 (5:25 pm)
If you have some time before surrendering it to the dealer, try this - take the driver's door switch out but leave it connected. On the blue connector there is an orange wire. This should have 12 volts direct from the fuse. Try to get a probe from a voltmeter into the back of the connector and put the other probe into the ignition switch (or another good ground) and see if you have a solid 12v. With the meter in the connector, try pressing on the lock and unlock to see if the voltage drops to 0.
If it drops (and nothing happens) you most likely have a problem between that wire and the battery – probably the fuse connector in the fuse block. Probably the easiest way around this is to run a good 12v line with an inline fuse to splice into the orange wire.
What I did was jam some copper strands in with the fuse legs, making the fuse legs a bit beefier and thus a better connection – it worked but I don’t know how long it will last – been working for a year so far.
#639 of 684 Re: 2005 Chevy Colorado Ignition Problems, Windows & Locks problems and more... [den052]
Feb 23, 2012 (2:27 pm)
"So, end result is that you and I are both right. A glitch can screw up a body computer and re-initalizing the computer straightens it out (at least untill it screws up again). "
Well, I wonder if it is a "Chicken and Egg" kind of thing. What if there is something like a poor ground which causes current to backfeed to a different ground is what causes the BCM "glitch" in the first place. Perhaps it fries the BCM or just gets it to throw false codes. The dealers happily replace the $400 dollar item because it is "bad". Maybe it is, maybe it's just the bad ground and confluence of circumstances which fried the BCM but may not happen for another two weeks or two years.
Possibly it goes the other way around. Perhaps these confluence of circumstances (poor programming code/errors) causes the BCM to not fully shut down sometimes and constant power is applied to the door module which burns it out and drains the battery. Maybe because of the dead battery the BCM "resets" in some way while someone tries one of the voodoo tricks like touching the leads together, cleaning all the grounds, sacraficing a virgin over the radiator or whatever and the window works, so whatever they tried becomes a 'solution'.
I sure as heck wouldn't want to troubleshoot the electrical system and component computer code to find a definite answer... and apparently GM doesn't want to waste the time either. It's just more lucrative to claim "Hecky-darned, imagine that, it's a bad BCM again, bummer for you, here's the bill... again" and collect the fee. Obama needs those reelection donation dollars rolling in!
#640 of 684 Re: 2005 Chevy Colorado Ignition Problems, Windows & Locks problems and more... [snaproll1]
Feb 26, 2012 (12:11 pm)
the politics in this post is incorrect. If you just post the problem generally on google, you would fined that other vehicles like toyota tacoma has similar problems as colorado. there is no escaping this problem. I am beginning to believe it,s a general problem throughout the industry. There is a lot of shared parts today.
My power door lock,window problem corrects it self. It goes off and on with out me doing anything. It started just a couple of years a go,around the sane tine My right blinker shorted out. thats the only problem I had so far, however. I had changed the battery after 6 years and the problem went away for the better part of a year, but now it,s back.
I love my truck an I plan on keeping it .I also have a 2010 toyota camry, that needs tires after only 20,000 miles and a lot of call- backs.
when i bought the camry I watched as the toyota dealer changed the frames on the tacoma,s because of sever rot.
After I was seeing how it comes and goes,i am thinking it,s a computer glitch .
#641 of 684 Re: 2005 Chevy Colorado Ignition Problems, Windows & Locks problems and more... [abczz]
Feb 26, 2012 (12:58 pm)
How about even more generally that we acknowledge that as consumers the more 'gadgets' we want on our vehicles, the more things there are to break and cost us time , money and frustration, regardless of the manufacturer!
Power windows, power doors, myriad vanity lighting and things have /always/ been sources of problems. Now we are demanding a whole new generation of problem-creators like bluetooth integration, navigation systems, drink chillers etc that will cause an additional layer of problems. If you want a more reliable, or less-costly vehicle to buy and repair, then buy them without all of the gadgets. Otherwire face the fact that they will cost you extra money eventually, no matter how well designed or reliable the component might be. Cars should have a body, seats, doors, engines, wheels and saftey lights. All else is essentially superfluous.
#642 of 684 Re: 2005 Chevy Colorado Ignition Problems, Windows & Locks problems and more... [abczz]
Feb 27, 2012 (6:57 pm)
"the politics in this post is incorrect. If you just post the problem generally on google, you would fined that other vehicles like toyota tacoma has similar problems as colorado. there is no escaping this problem. "
Ummmm, no. I don't agree with the "every vendor is the same" excuse. There is an obvious, reoccuring problem with the electrical system on the Colorados and Canyons that GM says "they never heard of" as they size up your wallet.
Perhaps you don't mind paying for something and not have it work, or paying for repairs that don't actually fix the problem but this goes way beyond that. You expect tires to wear out. You expect an alternator or starter to eventually go bad. You don't "expect" to have intermittent electrical failures of critical components like the battery, brake lights, windows, wipers, headlights, panel lights, fuse block not to mention the CD player, blower, blower resistor. How many vehicles have you owned that required a head replacement because of poor engineering?
True, every vendor can turn out a turkey product. What it comes down to is if they stand behind their product, not whether they stand behind Obama to stay in business.