Dash electrical problem-help

[OPAMP]

Issue:
After driving more than 20 minutes multiple dash issues begin.
They occur in the following order
1. always first the security light flashes on and off at a random interval.
followed by it staying on solid. Then the follow events occur rapidly [with in 5 more minutes of driving]
2 Check engine light comes on solid and stays on
3 Service engine light comes on and stays on.
4 tachometer and speedometer needles stop working and return to 0.0
5 randomly the shift arrow will stay lighted.
6 randomly the electric assist power steering stops working but i have to continue driving at least 5 minutes after the security light first comes on.
The engine continues to run now with no dash night lights or gages operating but the above warning lights remain lit. so far the engine has not stalled as long as i dont shut it off with this issue active.
7. When all this happens if your driving the power door locks will rapidly cycle close to open and back for a second or two. After that the power door locks no longer function until the fuse is pulled [ see below ]

i can key off a couple minutes but the security light will not go out
all the other lights go out. Now as long as the security light is on when i try to restart the vehicle it starts and stalls over and over.
to successfully start the vehicle i have to remove the 40 amp large battery fuse in the underhood fuse box and then plug it back in it. That unlatches the module that is failing or i suspect its a module.
I completely replaced the power feed wire with with the 80 amp fuse that supplies the koyo module bolted up by the power steering motor under dash. I also ran a second ground to the under dash ground for that feed. The proper gauge wiring was used to supply 80 amp continous supply. this was no help. I disabled the security system with the key logic so security wont arm when the doors lock by button.
I suspect a module is latching but i need to know which one and where it is located in the vehicle.
I went through pulling relays and fuses when this happens and the only way to reset the failing part is to unhook the battery ground or pull the battery feed fuse. in other words i can pull all the fuses out of the underhood fuse box
but the security light stays on unilt i pull that battery feed fuse. Then all is fine again for 20 minutes or so
2002 vue 2.2l 4 cyl 5 speed manual. no security in radio.
this car lost 2 rear wheel bearings and is now eating its third and 2 ign modules and 2 cats along with those. now what. we bought it new and it is maintained as it should be. 80754. miles
Thanks

[OhioVueBoy]

Sounds like the BCM is dying to me. Run a search, you'll find hundreds of threads for this.

~D.J.~

[IMkenNY]

Ill 2nd the BCM (body control module).
Its located under the radio.

I had sucess replacing a bad BCM with a used one (ordered it in from www.car-parts.com) and did the 30 minute passlock relearn precedure myself. The only problem doing it yourself with a used module is the odometer discrepancy (stored in the BCM) and you still need to have dealer reprogram keyless remotes which is an inexpensive procedure.

If you go with a new BCM it has to be programmed at the dealer and I believe the total cost with installation is in the $700 range

[OPAMP]

I believe you are correct. Currently I am looking for a used bcm and will do the 30 minute proceedure. I am also going to see what failed in my old bcm.
Since there are so many failures I am wondering if it is placed in a location where there is not enough cooling. I found when it starts to act up the small open tray under the radio is very hot down in the back. I also noticed if I don’t run my heater or defroster I can run much longer before the failing part goes into thermal overrun. When I figure out what part is failing in the bcm I will post it. I have never taken one apart so it may not be fixable due to
The component(S) used. I will let you know. Many times it is just a passive device like a resistor that drives flakey behavior like this. What is a good place to find the wiring, voltage inputs and logic for that device? The thing that irritates me is the amount of failure to population ratio. They should be recalling this. I just received my 2od postcard for the recall on my ign module. I went to the dealer with the first post card I got last year and told them I replaced it with an aftermarket and didn’t want their module in my car.
They said no problem as long as it’s replaced. So here we go again..Maybe I can scratch off ign module and type in BCM on my recall card :D. cheers
2002 vue 5 speed with 2.2 4 cyl.

[fdryer]

Good luck with performing an autopsy on your BCM as its going to be interesting. Take pics if you can for posting, I'm interested. And please take careful, focused pics, previewing them on your monitor before posting. I hate poorly posed images that some think are great when they're blurred or mistakenly posed up-close resulting in a completely out of focus useless picture. The few pics I've posted were all pre-screened so I won't suffer the rightful indignation of fellow members flaming me. :hothead: <ouch> :hothead:

The heat from any failed BCM may be from the failure and not from normal operation. Being a very important piece of electronics controlling almost everything not run by the ECM for engine control, ABS, and transmission control among the various subsystem computers, the BCM was probably placed in a secure area not requiring any ventilation as it doesn't need to control large current demanding components that would require large heat sinks for heat dissipation. Its mainly a group of large scale chips to handle the many sub routines communicating and controlling external circuits that consume current. This form of programmable logic computer can be tucked away in a safe place with the umbilical harness to tie it to the rest of the car.

[IMkenNY]

A schematic of the BCM would be nice, factory service manuals do not have this information.

The board/ components are covered in a thin layer of goo (technical term) to protect them from moisture.

There is one component that is actively heat sinked , perhaps its a voltage regulator that overheats.

[IMkenNY]

Link below is a 3mp pic of 2003 Vue BCM board/ components :

No picture flaming please :), inexpensive camera and little experience.


http://www.saturnfans.com/photos/showphoto.php/photo/50098/size/big/cat/500

[far2grumpy]

OPAMP ... to be honest ... I wouldn't recognize a Vue BCM if you dropped one on my foot. However, I've read enough about them to consider myself dangerous.

I've attached a few 02 Vue BCM interconnects from a service document.

The problem certainly sounds temperature driven (unless - of course - one of the power inputs or grounds are flaky).

Is it possible to use +12 mini-fan to direct airflow toward BCM? Not as permanent solution but for troubleshooting.

How about spraying "freeze-mist" to parts of BCM is see if it'll speed recovery?

[fdryer]

The lack of detailed schematics is most likely for several reasons - the complexity of on-board electronics utilizing several mini-computers renders these schematics useless to the average Saturn technician that these manuals are aimed at and the design of these subsystems precludes repairs by almost anyone if they fail. There are, to my limited knowledge, no factory repairs to these units that makes them cost effective to devote a bench repair station set-up for volume. This would suggest weakness' built-in to BCM's that were deliberately designed to minimize damage and make repairs cost effective. Replacing them outright seems to be the industry mantra for overall cost effectiveness and the failed ones simply tossed because of design not allowing for failure. As posted, the first BCM's to fail cost the most due to newness but as more cars/BCM's were sold and real world problems were noted, running changes were most likely done, as fewer similar incidents are being posted and repair costs came down. At least the ones posted here on Saturnfans. I would guess that BCM's are in every GM vehicle when, relatively speaking, Passlock anti-theft was first introduced. Very complex electronics dictates division of duties to sub system computers that in turn communicate to a central one for disseminating the ills of a stricken system. The BCM was tasked with this responsibility. I would be surprised if BCM's are repairable or even able to be re-programmed/flashed. Anyone familiar with repairing surface mount chips?

Being familiar with electronic maintenance/troubleshooting, the average maintenance tech is taught enough to be dangerous and only interested in board level diagnostics - signals in and out. If output signals aren't detected (the Techtool II) when signals/power are input, its a foregone conclusion that the pc board is faulty and simply replaced. Too many input signals and the many output signals in precise timing sequence requires a very well rounded background in electrical/electronic/computer systems fundamentals in digital logic. Not the realm of the average DIYer.

Excellent picture ! ! :yes:

[far2grumpy]

IMkenNY ... so, the BCM is not mounted in any sort of enclosure?

Do the connectors plug in to a chassis type apparatus, or, are the mating connectors on separate pendant type cables / harnesses.

fdryer ... I'm guessing anyone who chooses OPAMP for a screen name has more than a casual knowledge of electronics ... but then I'm assuming its the abbreviated form of operational amplifier and not one of the 100 gazillion contemporary terms that have passed an old coot like me by.

I also imagine you're right-on regarding throwaway versus repair status of the BCM circuit board. I think I recall a recent post where someone had a dealer replace the BCM for around $400 USD which sounds like a bargain.

Finally, I'm intrigued by the thought that somewhere on this little piece of fiberglass, epoxy and silicone resides at least part of the circuitry necessary to keep track of miles, kilometers, etc traveled by the host vehicle.

Can you imagine the damage to consumers should unscrupulous dealers, or even individuals, have the capability to access and program, or reprogram, vehicle mileage using the BCM? :no::yes:;)

The question is obviously in jest ... if I thought of it ... someone has been doing it since digital devices were installed on vehicles.

[IMkenNY]

Federal law requires all automotive BCM computers to be in "a little black box"


Im kidding :), see pic below:

http://www.saturnfans.com/photos/showphoto.php/photo/26066/size/big/cat//ppuser/5260

Connectors to the BCM are part of a main wiring harness.

I now own a tech2 , sis software and two spare BCMs. I hope to try to reflash a BCM in the spring.

On a side note, my 2007 Redline Ion BCM was getting very confused when the voltage regulator in the alternator caused a sporatic overcharging/ undercharging condition. The new alternator solved the problem without a BCM replacement.

[far2grumpy]

Your comment to ensure a stable voltage source was spot-on!

Regarding BCM programming ... I'm thinking someone could make a lot of honest money by programming BCM's by mail.

Lets say you had a test setup or mock-up with basic wiring (or you could use your Redline Ion - yeah right).

Customer could send you ...

1. Payment
2. BCM from salvaged vehicle or other source
3. Ignition key with keyless entry fob
4. VIN
5. Notarized vehicle mileage statement
6. Other required material or data

Could you - in theory - program a BCM and return to customer?

[ssicarman]

As far as I know the BCM needs to be programmed in the car. It needs to be able to speak to the other modules. The aftermarket may have gotten around this but I have not seen anything.