08 Uplander Gives only 8888 on OBDII reader

[autojoe]

2008 every vehicle has to be can compliant.i was thinking this tool could go in under the obd 2 global side.if you like doing this kind of stuff i would invest in a better scan tool.ebay has lots of used ones depending on price and functionality.by 2012 all vehicles have to have stability control then there is the tpms the tire pressure monitoring system manditory by 2008.everything keeps evolving.

[quickcurrent]

It looks like the evolution is a lot like all other computers. I paid over $200 for mine with limited capabilities, now I see there is a $17.39 unit here http://www.dinodirect.com/ms300-obd2...Fck-MgodUVwA6w

that does way more, although it doesn't look as rugged as mine made by a division of Bosch. But it looks like they get outdated before they get broken, lol.

I also just found out that one of my local auto parts suppliers (one block away from my house) will let me use an Innova unit with CAN protocol in their parking lot for free. So I'll see if his unit can read my trouble code(s).

[quickcurrent]

This saga gets wierder and weirder - went to my local parts supplier, hooked up their CAN OBD-II reader, communicated with the PCM OK, but found no data to read, tried it again, same thing. The "check engine" light has gone out. It drove fine there and back and started normally.

At first, it looks like there is nothing wrong with the vehicle, but I am not so sure...

How could the data just all disappear? Could probing the pins on the DLC with the multimeter do that? Could it have happened when I was pushing all three buttons (read, clear, reset) on my non CAN reader do that without communicating with the PCM to read data? Or could pulling fuses do that? I assume that the data is held on a chip that is not volatile, i.e. does not require power to hold data in storage like RAM does on a PC.

[Tech II]

Exactly what kind of info did you get from this scan tool?

Did it read codes? History codes?

What data were you trying to read?

In my last post, those voltages were wrong....did you double check them?

[quickcurrent]

Originally Posted by Tech II

Exactly what kind of info did you get from this scan tool?

Did it read codes? History codes?

What data were you trying to read?

In my last post, those voltages were wrong....did you double check them?

The voltages are the same as before, I got the same voltages several times. I think maybe the multimeter is off.

The CAN reader just said something like - no data found to read.

When the reader couln't find anything after communicating via the CAN protocol, the fellow there helping me said that trouble codes usually display automatically with that reader, but just to make sure, he pushed a button to re-read - again same message!

[quickcurrent]

Another detail that I had forgotten about is that after 10 minutes or so of being driven, the vehicle starts to shake like the fuel air mixture is off (running rough). It did that before it stalled and has done it again today twice during a 15 minute drive to a place and 15 minutes back.

This could be the lack of data preventing the PCM from knowing exactly how to optimize the fuel air mixture and guessing at it. The air filter was replaced some 6,000 miles back so that should be OK. Since there is no data I can't know if it's the oxygen sensors acting up or just data loss.

So it all comes back to the question - how could all data have been lost during normal driving or from the testing I did on it?

[autojoe]

the lack of data is your scan tool failure to communicate.have to hook up a good scan tool to see if it could communicate with the pcm or any other module on the bus.at that point there would be u codes or communication codes.there are failure backup modes backup stradegies that the pcm uses.I dont put too much faith in the scan tools that parts places sell.they are limited.

[quickcurrent]

Originally Posted by autojoe

the lack of data is your scan tool failure to communicate.have to hook up a good scan tool to see if it could communicate with the pcm or any other module on the bus.at that point there would be u codes or communication codes.there are failure backup modes backup stradegies that the pcm uses.I dont put too much faith in the scan tools that parts places sell.they are limited.

Thanks, I was wondering about that tool, the Innova scan tools are not rated very high . I'll have to call the shop on Monday, see if they can read anything with theirs.

[quickcurrent]

The dealer replaced the PCM and reprogrammed it under the vehicle's 5 year power train warranty. I've had it about 4.5 years.

[j cAT]

Originally Posted by quickcurrent

The dealer replaced the PCM and reprogrammed it under the vehicle's 5 year power train warranty. I've had it about 4.5 years.

now the PCM being defective can occur if the voltage to it , is too high .the other cause would be poor ground connection , and the battery connections to the vehicle fuse panel are not in good condition/clean secure.

jumping or being jumped can very easily kill the PCM if not done properly.

[quickcurrent]

Originally Posted by j cAT

now the PCM being defective can occur if the voltage to it , is too high .the other cause would be poor ground connection , and the battery connections to the vehicle fuse panel are not in good condition/clean secure.

jumping or being jumped can very easily kill the PCM if not done properly.

I suppose it could be a number of things. But you forgot to mention a defective/inferior quality board from the factory. Given the number of defective parts I have come across on GM vehicles recently, many failing long before their normal life expectancy, that would be my first guess! I wonder if GM buys their boards from that crappy Asian manufacturer that makes the iphone with chid labor! The name is Foxconn, they produce nothing but trash!!!

[j cAT]

Originally Posted by quickcurrent

I suppose it could be a number of things. But you forgot to mention a defective/inferior quality board from the factory. Given the number of defective parts I have come across on GM vehicles recently, many failing long before their normal life expectancy, that would be my first guess! I wonder if GM buys their boards from that crappy Asian manufacturer that makes the iphone with chid labor! The name is Foxconn, they produce nothing but trash!!!

since this is an old vehicle the records show not much of an issue with the PCM.

like I stated before if the electrical supply is screwed up it will fail. same is true with all these crappy Asian TV sets. you have surges on the house power the same fail will result.

other parts like switches/controls ,,, well that is part of the game they all play unless you purchase a high quality expensive vehicle like over $80,ooo.

these cheap low quality vehicles are designed to fail after several years like 7 years under normal use. After 7yrs/120,000 miles you can expect much repair work to the interior/plastics/body /rubber seals etc...GM electrical engine systems appear to still be made with good reliability. if the engine controls are crap , this would be a recall and then that , would cost GM much money , and then the loss of sales .

if that cheap door handle falls off there will be no recall so they make these parts as cheap as possible. they want you to buy new every 7 years.

welding on a vehicle and not removing the negative battery terminal is another cause of PCM failure to the loose ground of the PCM. these will surely cause the PCM to crash .