08 Uplander Gives only 8888 on OBDII reader

The other day I was driving home and my '08 Uplander stalled on a busy intersection. Needless to say everyone behind me started honking their horns like the Italians had just won the world cup!

After several tries I was able to get it started and drove home with the "check engine light" on.

I took out my OBDII code reader and all I can get is 8888. I've checked the PCM fuses - OK, I've checked the PCM connector under the dash - looks OK. I made sure to have the ignition to ON with the reader connected. According to the OBDII manual the PCM is not communicating with the reader. Looked for the PCM to check the ground connector, but can't determine where the PCM is located under the hood. As far as I can determine it could be a broken wire, a bad ground connection perhaps with rust on it (although I doubt that, there is very little rust on the vehicle since it gets oil sprayed every two years or so and has only 35,000 miles on it), or a bad PCM.

Any thoughts on likely cause? Anyone know where they've hidden the Powertrain Ccontrol Module?

TIA,

quickcurrent

PCM is under the cover on top of the air cleaner assy...

check fuse 6 onstar 10 amp fuse block under dash.

Thanks gmtech1, maybe now I'll be able to find that ground and check that.

I didn't realize there were more fuses in addition to the ones in the plastic case under the hood on the passenger side, autojoe, but I will look for it, thanks.

Hopefully it doesn't end up being a PCM gone bad. :frown:

ground pins 4&5 of obd 2 connector.one is chassis ground and one is sensor ground.both go to same grounding point.g200.most of the time it is a power feed issue to pin 16.i believe the fuse block is on the right hand side of ip.
48770
1 - G200
2 - Blower Motor
3 - Blower Motor Resistor Assembly
4 - Recirculation Actuator
5 - Inflatable Restraint Instrument Panel Module
6 - Fuse Block - Instrument Panel
7 - Evaporative Temperature Sensor
8 - X205 (CJ3)

g200 located on the right side of the ip support beam above the ip compartment.your scan tool needs a power and ground.

Did your code reader previously work with the vehicle?

Did your code reader previously work with the vehicle?

It has worked with several other vehicles in the past, just recently. I've never needed to use it on this one before as best as I can remember. I am assuming the 08 Uplander is OBDII compliant.

OK, just looked under the dash, couldn't see any fuses. Are those fuses behind the felt cover panel under the dash, if so, what side?

Looked at the cover the PCM is under - wow - looks like I'd have to remove a bottle and a steel brace before I could get at it to open the cover! Where does the ground go, I also could not see any wires coming out from underneath the cover! Do they go down? If I can find the ground connection and find that there is rust on it, I may not have to start taking the vehicle all apart.

look at above illustration.....fuse box on right side of ip.also shows the ground point location for pins 4&5 of obd 2 connector.check fuse 6 first to see if blown.check obd 2 connector terminal 16 bottom right 2 rows of 8.1-8 top and 9-16 bottom....check with voltmeter for b+. yes obd 2.

autojoe, my fuse 6 is fine. I get no current at pin 16 of the OBD-II connector. The illustration you have posted looks nothing like anything I can see under my hood! So I have no idea where those ground connections are. But it looks like the fact that I get nothing at pin 16 tells us that there is a discontinuity in that wire. The problem is finding the break!

thats under dash right hand side.do you have battery voltage at pin 16 of obd 2 connector?current flow only while scan tool connected.voltage pontential 12 volts.what kind of scan tool?code reader?

i would try another scan tool.get a hold of the code reader company tech support.i have dealt with many no communication problems including the new can systems but i have a snap on solus pro/escan/autoenginuity.I mainly use the snap on.8888 is only related to your reader.

OK, autojoe, I connected my multimeter to the pin without the OBD-II code reader, hot to pin 16, ground to a metal part nearby, with ignition to ON, and got nothing. Once the reader is connected I can't get the multimeter probe in there!

My code reader is an Actron CP9035, it's always worked just fine on other vehicles!

then power feed pin 16 good.take positive probe to pin 16 a negative meter to pin 4 then pin 5.should be same battery voltage pontential as you got on above tests.i didnt mean for you to do with scan tool hooked up.you just want to make sure you have battery voltage on pin 16 and pins 4/5 grounds are good.what voltage did you get when meter positive to pin 16 and negative meter to good ground?I always run a jumper to battery negative terminal....the best ground on vehicle.you could do a ground to ground voltage drop test.......run a jumper to negative battery terminal and run inside car then hook positive meter to pin 4 and negative meter lead to battery negative terminal via the jumper and start car and see what the reading is....now do same on pin 5........

then power feed pin 16 good.take positive probe to pin 16 a negative meter to pin 4 then pin 5.should be same battery voltage pontential as you got on above tests.i didnt mean for you to do with scan tool hooked up.you just want to make sure you have battery voltage on pin 16 and pins 4/5 grounds are good.what voltage did you get when meter positive to pin 16 and negative meter to good ground?I always run a jumper to battery negative terminal....the best ground on vehicle.you could do a ground to ground voltage drop test.......run a jumper to negative battery terminal and run inside car then hook positive meter to pin 4 and negative meter lead to battery negative terminal via the jumper and start car and see what the reading is....now do same on pin 5........

Thanks bud, I have a little more testing to do. I'll post results later.

Alright, just finished testing my pins.

Ignition to ON, multimeter set to 20V, hot to pin 16, common to pin 4, reads 16.8.
Hot to pin 16, common to pin 5 reads 16.8. Hot to pin 16, common to a pedal reads 16.8. So now I've established that there is juice going to pin 16. Don't know why I got a reading of 0 before!

Tested the OBD-II reader on a Stang, works fine. Tested it on this Uplander, gives me 8888. I've used it before on an Olds and a GMC, worked fine on those too. Seems incompatible with this vehicle. If the vehicle is OBD-II compliant, then it must be a software incompatibility, it seems!

Looks like I have to take it to the shop, because I don't have another scan tool. But, I am concerned that the darn van will leave me stranded somewhere and I'll have to get it towed. Any ideas what might be causing the van to stall because of a "check engine light" so I can do a visual check before I take it in?

Just checked the pin positions on the Uplander connector and compared it to the OBD-II reader. This is what I found!

Connector has pins at positions 2,4,5,6, 14 and 16, all other positions are blanks.

The OBD-II reader has pins at positions 2,4,5,7,9,10,16, all other positions are blank.

Does this not mean that the Uplander is not OBD-II compliant? Aren't all vehicles built since 1996 required to be OBD-II compliant by law?

Hmmmm....

Just checked the pin positions on the Uplander connector and compared it to the OBD-II reader. This is what I found!

Connector has pins at positions 2,4,5,6, 14 and 16, all other positions are blanks.

The OBD-II reader has pins at positions 2,4,5,7,9,10,16, all other positions are blank.

Does this not mean that the Uplander is not OBD-II compliant? Aren't all vehicles built since 1996 required to be OBD-II compliant by law?

Hmmmm....

with the ignition switch to on , engine off and the code reader connected your getting the 8888 error code . this will show if you have too much voltage or too little . voltage should be 10-15 volts on pin 16 to ground.

using a meter check all fuses for open/blown condition. make sure pins on the vehicle diagnostic connector are NOT pushed in ,

with the ignition switch to on , engine off and the code reader connected your getting the 8888 error code . this will show if you have too much voltage or too little . voltage should be 10-15 volts on pin 16 to ground.

using a meter check all fuses for open/blown condition. make sure pins on the vehicle diagnostic connector are NOT pushed in ,

OK, are you suggesting that any one fuse that might be blown in the fuse block could increase the voltage to the diagnostic connector? The pins are not pushed in, they all look good. What about the pin-out differences?

OK, are you suggesting that any one fuse that might be blown in the fuse block could increase the voltage to the diagnostic connector? The pins are not pushed in, they all look good. What about the pin-out differences?

with your comment this indicates to me you do not know much about these systems or the electrical supply circuitry.

a blown fuse will cause the error you are getting. this feed devices that are part of the diagnostic circuitry.

with the engine off and ignition switch to on //// If you get over 12.5 volts then your meter is defective.

with the engine running and you get over 14.75 volts then the alternator is defective with a meter that is working [calibrated] ..................

then the pushed in pins on the vehicle diagnostic connector.

any fuse that is blown may be the cause of this error ! so using a meter that works check each fuse for being damaged/open .

if this is done and your not successful you will need a repair tech with the wiring diagrams to search out the failure of the diagnostic system.

good luck.

Pin 2 is class II data...6 and 14 is for CAN.....

I believe he stated he has ground at 5 and 4...and power at 16......question is, is he getting class II data from pin 2....Attach voltmeter to 2 and 4...turn key to on......if voltage is constant and not changing, there is a problem with the Pin 2 circuit....

with your comment this indicates to me you do not know much about these systems or the electrical supply circuitry.

a blown fuse will cause the error you are getting. this feed devices that are part of the diagnostic circuitry.

with the engine off and ignition switch to on //// If you get over 12.5 volts then your meter is defective.

with the engine running and you get over 14.75 volts then the alternator is defective with a meter that is working [calibrated] ..................

then the pushed in pins on the vehicle diagnostic connector.

any fuse that is blown may be the cause of this error ! so using a meter that works check each fuse for being damaged/open .

if this is done and your not successful you will need a repair tech with the wiring diagrams to search out the failure of the diagnostic system.

good luck.

You're right on. I have only a basic understanding of electrical circuits. If I had advanced knowledge of them I would probably be here offering advice rather than looking for it. It just didn't make sense to me that a circuit that is open on account of a blown fuse would affect other circuits, as circuits are typically independent of each other. The suggestion of the meter being out of calibration makes more senses to me.

Given my limited knowledge of these things in particular, however, yours and all other suggestions are appreciated.

I have never had a vehicle's on board computer fail on me, particularly on a vehicle with the original brake pads still on it! I guess that says something about the quality of GM parts, if it turns out that the PCM is indeed kaput, doesn't it?

In the meantime I've got some more checking to do.

Pin 2 is class II data...6 and 14 is for CAN.....

I believe he stated he has ground at 5 and 4...and power at 16......question is, is he getting class II data from pin 2....Attach voltmeter to 2 and 4...turn key to on......if voltage is constant and not changing, there is a problem with the Pin 2 circuit....

I'll check this and post results, thanks, bud.

OK, guys here are the results of my further testing:

1) All fuses are good.
2) Ignition ON, get same results as above (16.8) between pins 16-4 and 16-5.
3) Engine running, get a reading of 1 between pins 16-4 and 16-5.
4) Ignition ON, get a fluctuating value between 1 and 2 between pins 2 and 4.
5) None of the pins are pushed in.

Any other ideas?

need specialized equipment.need a dlc breakout box and a labscope.also need a scan tool capable of communicating with all modules on the bus.you may have a shorted bus.if you knew someone that had a good scan tool and see if they could communicate with any of the modules on the bus.if any u codes which are communication codes.

need specialized equipment.need a dlc breakout box and a labscope.also need a scan tool capable of communicating with all modules on the bus.you may have a shorted bus.if you knew someone that had a good scan tool and see if they could communicate with any of the modules on the bus.if any u codes which are communication codes.

I was afraid that would be the case. Thanks autojoe. I suppose I'll have to attempt to drive it to the shop and be prepared for a tow job. The vehicle starts OK on the driveway, just don't know if it will behave all the way to the service shop. Can the modules be replaced individually or does the PCM need complete replacement if there is a short/crack on the MoBo? What's the ball park cost to replace the unit?

Well, I contacted Actron about this issue and here is what they had to say, just received.

"Starting in 2004 to make the government mandated requirement all manufacturers started switching to the CAN protocol. Your cp9035 is not capable of reading vehicles on this protocol due to the faster baud rate that the information is being transmitted. There is no way to update or upgrade your tool to correct this. The hardware of your tool is not compatible. You would have to purchase a new CAN capable tool to read your vehicle.

Bosch Automotive Service Solutions
ACTRON TECHNICAL SUPPORT

Bosch Automotive Service Solutions
655 Eisenhower Drive
Owatonna, MN 55060"

Perhaps it's not as bad as I was starting to fear, if it's simply the tool unable to read this PCM. This partly explains the differences in the pinouts too.

I found a very good write-up on the pins of the DLC, that explains a lot, for those of you that may run into this same issue that I am having, here
http://reviews.ebay.ca/Scan-Tool-Diagnostics-amp-Programing-for-OBD-2-amp-CAN-BUS?ugid=10000000017626434

OK, guys here are the results of my further testing:

1) All fuses are good.
2) Ignition ON, get same results as above (16.8) between pins 16-4 and 16-5.
3) Engine running, get a reading of 1 between pins 16-4 and 16-5.
4) Ignition ON, get a fluctuating value between 1 and 2 between pins 2 and 4.
5) None of the pins are pushed in.

Kind of thought your reader was not compatible with CAN.....

However......

With the ignition "on", and vehicle not running, you should get BAT voltage(12.6 max) on line #2, not 16.8 volts.....

On line #3, with car running, you should get alternator voltage, 13-14 volts, not 1 volt....

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.

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-code-reader-tool-obdii-diagnostic-scan-tool.html?cur=usd&affid=4434&source=sem&daf=yes&gclid=COX3vP7li7cCFck-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).

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.

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?

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!

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?

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.

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 :mad:. I'll have to call the shop on Monday, see if they can read anything with theirs.

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.

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.

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!!!

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 .