Electrical Headache! please help.. 96 cav - Page 2

manicmechanix · #16 03-21-2009, 08:07 PM

Quote:

Originally Posted by boomer3

Thanks for the help guys, ill get back to you within a week or so.. As for the reprogramming, it was tried numerous times, using the original eprom chip, and another eprom chip, with a snap-on scan tool, i really feel that the likelyhood of that being done wrong is low. But dont quote me:P.

This doesn't make much sense to me. A '96 is obd2 and doesn't have a prom chip just a programable prom. Also I don't think a snap-on scanner can program the PCM only a GM Tech2 scanner tool can. That's my understanding of it. It doesn't sound like the PCM got reflashed properly.

J-Ri · #17 03-21-2009, 08:24 PM

Quote:

Originally Posted by manicmechanix

This doesn't make much sense to me. A '96 is obd2 and doesn't have a prom chip just a programable prom. Also I don't think a snap-on scanner can program the PCM only a GM Tech2 scanner tool can. That's my understanding of it. It doesn't sound like the PCM got reflashed properly.

Not sure about the chip in 96... but yes, only the Tech2 can program GM cars.

What exactly did you do with the Snap-on scan tool and which model is it?

manicmechanix · #18 03-22-2009, 03:13 AM

Quote:

Originally Posted by J-Ri

Not sure about the chip in 96... but yes, only the Tech2 can program GM cars.

Pretty much all '95 GM that I've seen at least are flashed programmed and all '96 up are obd2 and definitely flash programmed. Well you just verified that only a tech2 can program the PCM, so it looks like the original poster never got his PCM programmed.

boomer3 · #19 03-22-2009, 03:50 AM

The problem here may be that i am not giving perfectly accurate information. For one, i simply thought the removable chip was called a prom chip, or eprom chip, and either way i tried reflashing with 2 chips. Second, i thought it was a snap-on scan tool, with a gm program on it. It is not mine, but a fellow that often works on cavaliers and has had to flash them many times.. (according to him). It was a large red handheld scan tool, and he had to input the vin, along with a few other things, and had to let it sit for 5 or 10 minutes while waiting for it to flash. Either this was the gm tool and reflashing doesnt cut it, or he used the wrong tool, and took my money. Sorry for the confusion folks.

rhandwor · #20 03-22-2009, 08:15 AM

Try using contact cleaner and installing the original e prom chip. You can have a bad switch but a resister will take care of this problem.
http://www.ntxtools.com/ Search 3606 This is a picture of a tool but is more than you may want to pay.

J-Ri · #21 03-22-2009, 12:40 PM

Quote:

Originally Posted by boomer3

The problem here may be that i am not giving perfectly accurate information. For one, i simply thought the removable chip was called a prom chip, or eprom chip, and either way i tried reflashing with 2 chips. Second, i thought it was a snap-on scan tool, with a gm program on it. It is not mine, but a fellow that often works on cavaliers and has had to flash them many times.. (according to him). It was a large red handheld scan tool, and he had to input the vin, along with a few other things, and had to let it sit for 5 or 10 minutes while waiting for it to flash. Either this was the gm tool and reflashing doesnt cut it, or he used the wrong tool, and took my money. Sorry for the confusion folks.

I can't say I've ever heard of GM software for a snap-on scan tool, but if he's done it before, I sure won't argue with that without any experience there myself. We have a Snap-on and a Tech-2, and if the Snap-on was capable of what the Tech-2 is, I don't think the owner of the shop would have spent $7,000 on the Tech-2. The Tech-2, the GM factory tool is dark grey and about half the size of the snap-on scan tools, so it was not the GM tool he used. In the "MODIS", the most popular snap-on scan tool, you have to enter part of the VIN to identify the vehicle, but can't actually do anything for programming. As far as I know, the "Big 3" allow only their scan tool to do programming.

manicmechanix · #22 03-22-2009, 04:22 PM

Quote:

Originally Posted by J-Ri

I can't say I've ever heard of GM software for a snap-on scan tool, but if he's done it before, I sure won't argue with that without any experience there myself. We have a Snap-on and a Tech-2, and if the Snap-on was capable of what the Tech-2 is, I don't think the owner of the shop would have spent $7,000 on the Tech-2. The Tech-2, the GM factory tool is dark grey and about half the size of the snap-on scan tools, so it was not the GM tool he used. In the "MODIS", the most popular snap-on scan tool, you have to enter part of the VIN to identify the vehicle, but can't actually do anything for programming. As far as I know, the "Big 3" allow only their scan tool to do programming.

That's my understanding as well that a Snap-on scanner can't programming a GM PCM and neither can any other scanner besides the Vetronix Tech-2 and the Vetronix Mastertech (similar to a Tech 2). I have heard that there's was a standard after '04 that an aftermarket "Passthru" device will allow you to connect a laptop and with a subscription to the GM calibration software you can then program the PCM. But an aftermarket scan tool wouldn't be in the picture anyway. Now, I don't know if this works on pre-'04 but I think so.

I'm still confused about the poster mentioning "chips". If he's talking about the EEPROM I didn't know that was replaceable separately. Maybe he means PCMs, but I'm not sure where he got the 2 different PCMs. OP, why can't you clean up the terminals and put the old PCM back in?

boomer3 · #23 03-22-2009, 06:02 PM

I pulled the original pcm out of the vehicle in 2 pieces it was so corroded, completely unusable. Even the plugs were severely corroded, and i had to splice new plugs in. On the 96 cavaliers i know that they all used the same pcm no matter what options the vehicle had, this pcm has a removable plate, and below that plate is a prom chip that can be easily removed. I got the second pcm out of another cavalier in perfect shape, and so i have 2 prom chips now, one from the original, and one from the 'new' pcm. As for the scan tool, i cant continue to comment, it would just be speculation.

J-Ri · #24 03-22-2009, 07:30 PM

Quote:

Originally Posted by boomer3

On the 96 cavaliers i know that they all used the same pcm no matter what options the vehicle had

I don't think that's true. I'm 99% sure the 2.2 and 2.4 engines have different PCMs.

boomer3 · #25 03-22-2009, 07:37 PM

Yes, as long as its the 2.2, the pcm will be the same. Ie, even if you pull it from one with an auto tranny, and other options that your car doesnt have, the pcm will still be ok to use.

manicmechanix · #26 03-22-2009, 08:05 PM

Quote:

Originally Posted by boomer3

Yes, as long as its the 2.2, the pcm will be the same. Ie, even if you pull it from one with an auto tranny, and other options that your car doesnt have, the pcm will still be ok to use.

Well a PCM another 96 2.2 from AT car won't work right on a manual car and vice versa. You realize that the PCM has the VIN number of each specific car? I think the replacement PCM is going to need be reflashed. You say you think the vehicle theft system is activating. When you turn the key to ON does the Theft light come and then go off while cranking?

boomer3 · #27 03-22-2009, 10:33 PM

They are completely interchangeable, you just need to have them flashed. You have to understand that the piece of the pcm that stores memory(ie vin), is the eprom chip that i've talked about so many times. When you put in a new one, it requires reflashing, which as i said has been done unsuccessfully. This is specific to 1996 however. It is a solid light prior to crank, and flashes 2 seconds after start which inturn shuts the fuel off, then it goes back to solid.

manicmechanix · #28 03-22-2009, 10:59 PM

Quote:

Originally Posted by boomer3

They are completely interchangeable, you just need to have them flashed. You have to understand that the piece of the pcm that stores memory(ie vin), is the eprom chip that i've talked about so many times. When you put in a new one, it requires reflashing, which as i said has been done unsuccessfully. This is specific to 1996 however. It is a solid light prior to crank, and flashes 2 seconds after start which inturn shuts the fuel off, then it goes back to solid.

Right, it's not going to work until it's reprogrammed. What I was saying is if you put aside the VIN compatibility it could theoretically run fine without reprogramming if the replacement 96 PCM came out of the same engine and transmission, but it's a mute point since it has to be reprogrammed regardless.

Well it sounds like your theft deterrent is shutting the engine down. It's probably not a problem in the theft system its self, it's probably because the PCM has to be reprogrammed to the calibration with that car's VIN to pass theft deterrent.

rhandwor · #29 03-23-2009, 08:09 AM

This company sells rebuilt and also reflashes computers.
http://www.autocomputerexchange.com/Repairs
Call for a price on a reflash.

boomer3 · #30 03-24-2009, 08:56 PM

I just had a look at it today finally, and found that there is a ribbon of 3 wires, going directly into the tumbler, and must be in the 20 ga range they are so small. If a picture would help let me know. My problem is that they are all black. One side of the ribbon has a white stripe down it however. Is this the group of 3 wires i should be concerned with?.. I cant find anything else closer to what has been discribed. There are no 'yellow', and 'white' wires as i was instructed about, but perhaps they weren't always that colour depending on time or location of manufacture?

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