UPS unable to scan

topfuel341 · June 30, 2010

Hi, everyone! I have a p700 vin# 5B4KPD25973426076 (2007)

Driver complaint.. engine running funny. I used our shop SBDT, and was unable to scan. No com port. I had my personal OTC scanner at the shop, and it showed no codes on the j1939. However on the j1708/j1587 it had all six injectors below normal or open, and 078 eng#1 fuel pump actuator bad. I was able to clear the codes, and road test, no codes. Truck runs fine.

My question is, why cant I scan with the shop computer, but I can with mine? Also does this look familiar to any one? Am I looking at and IDM issue, or... hate to say it EGR cooler?

Bruce Amacker · June 30, 2010

Are you familiar with data bus diagnostics for the J1708 circuits, what the voltages should be, and how to disconnect modules (nodes) on the bus to isolate the ECM? That's where I'd start regarding the communications problem. Does the shop's computer work fine on other trucks?

What OTC scanner are you using- Genisys with HD? I wouldn't trust it if I were you. Is a SBDT similar to an old SBDS? A UPS branded laptop or software?

Sorry for all of the questions....

Good Luck!

Posted Image

topfuel341 · June 30, 2010

Hi, Bruce! I am familiar with the j1708, but most of my training was from Ford and GM, and mostly on gas jobs. I left the dealer scene in 2002, and have slipped into the UPS black hole! We kinda lose touch with the outside world here, and can be a struggle without proper training! I do keep involved through side work, and whatever I want to learn here, and we see some interesting problems. So to answer your questions, I believe we are looking at 0 to 5v? I do have pinpoint specs in our shop manual, from International. I have not had the chance to disconnect nodes on the serial bus, to diagnose. Our SBDT is similar to the SBDS... we need major help in that department! LOL! We run INTL, Cummins 6BT, ISB, ISB07, Mercedes MB904, and GM small block, and big block gas.... All of which we have factory programs installed in the SBDT. We also have Allison as well. Because my resorces are not as intense or current as the dealer would have, I usually send most of this kind of work out. I am trying to hang on to whatever diagnostic daylight I can, in hopes not lose complete touch! Last question, was about my scanner. I have a small hand held HD reader from OTC that will give me j1939, j1708/j1587 so I can read engine, trans, and abs codes. I can not monitor PIDS. I used it here in the past, and compared it to the SBDT and so far so good! Do you know of any issues with this type of scanner, am I wasting my time using it? Thanks for all the help!

Bruce Amacker · July 1, 2010

Hi, Bruce! I am familiar with the j1708, but most of my training was from Ford and GM, and mostly on gas jobs. I left the dealer scene in 2002, and have slipped into the UPS black hole! We kinda lose touch with the outside world here, and can be a struggle without proper training! I do keep involved through side work, and whatever I want to learn here, and we see some interesting problems. So to answer your questions, I believe we are looking at 0 to 5v? I do have pinpoint specs in our shop manual, from International.

The IH stuff (and probably Ford's too) is WAY too broad, and there is a TON of misprints in IH's voltage pinouts. Copied from my Multiplexing book:

All MD/HD truck mfr’s Multiplexing Use at least two types of Data Links since 2000, J1708 (low speed) and J1939 (high speed) bus.

The J1708 Consists of a two wire copper twisted pair with no shielding.

Colors are usually blue and gray

The J1939 or high speed CAN (Controller Area Network)

May be a twisted pair unshielded, or a twisted pair, shielded, with a drain (ground) wire.

Also called the “Backbone”

Colors are usually green and yellow

Checking a typical J1939 9 pin Deustch Data Link:

A- Ground (-)

B- Battery Positive (+)

C- J1939 CAN (H)usually about 2.6v, depending on communication taking place

D- J1939 (L) usually about 2.4v, depending on communication taking place

E- CAN Shield

F- J1708 ATA (+) usually 3-3.8v, depending on communication taking place

G- J1708 ATA (-) usually about 1v, depending on communication taking place

H- Not used

J- Not used

Hook a Fluke 88 or DVOM with Min/Max across the C and D terminals of the Deutsch connector

Set the DVOM on resistance, with the Min/Max enabled. Disconnect batteries. Resistance should be between 55-65 ohms.

Go around the truck and wiggle the data bus lines looking for opens or shorts

Check the DVOM for a min/max outside of 55-65 ohms.

If the resistances spikes to 0 ohms- intermittent short, or rubbed harness.

If the resistances spikes to 120 ohms, there is an intermittent open.

I have not had the chance to disconnect nodes on the serial bus, to diagnose.

Just like on a telephone party line, we can have a blabbering drunk that won’t let anyone else talk. This basically prohibits the phone from being used, or “takes down the bus”.

Who’s likely to be the blabbering drunk? Maybe it’s Uncle Elmer after some whiskey, but on the bus it’s usually the ABS module or QualComm (or other aftermarket device that rides the J1708 bus).

Bus problems? No communication with the scan tool? See if there are any aftermarket devices on the bus: Lojack, theft devices, remote start, satellite communications devices, etc.

How do we diagnose this?

Check circuit voltages to identify if there’s a problem

Disconnect modules until:

The problem goes away

Only the ECM and Diag connector are left (if necessary)

If the problem still exists, it’s either a wiring problem or a bad ECM

Overlay the ECM harness from the Diag connector to the ECM

(Modules are commonly called “nodes” in service literature)

Our SBDT is similar to the SBDS... we need major help in that department! LOL! We run INTL, Cummins 6BT, ISB, ISB07, Mercedes MB904, and GM small block, and big block gas.... All of which we have factory programs installed in the SBDT. We also have Allison as well. Because my resources are not as intense or current as the dealer would have, I usually send most of this kind of work out. I am trying to hang on to whatever diagnostic daylight I can, in hopes not lose complete touch! Last question, was about my scanner. I have a small hand held HD reader from OTC that will give me j1939, j1708/J1708 so I can read engine, trans, and abs codes. I can not monitor PIDS. I used it here in the past, and compared it to the SBDT and so far so good! Do you know of any issues with this type of scanner, am I wasting my time using it? Thanks for all the help!

What's the PN of the scanner?

Now, to be specific with your truck, I am going to ASSUME it is wired similar to a VT275 IH CF600 or Ford LCF truck. You’re working on a P-model UPS bread van, and I don’t know how UPS spec’ed them. ISIS online does not recognize the VIN so I’m using CF600 stuff.

1. I don't think the ABS is on these busses. It shows as being on a separate J2284- can Keith or someone comment on this?

2. If it's wired like a VT275 there might only be 4 things on the 1939 bus- ECM, IDM, Dash cluster, and tranny.

3. Do you have the EGED 310 big color schematic and diag sheet for the VT275? If not, e-mail me at bamacker@aol.com and I'll send it to you. If you work on other IH engines and don't have the diag sheets, let me know. I uploaded all (60?) of them a while back for you guys to download, they are worth their weight in gold.

Good Luck!

Posted Image

PS I've got a separate "Bus Diagnostics" class that I'm doing next winter in Chicago and Grand Rapids that are public classes. Anthony will be doing IH AC and ISIS.

topfuel341 · July 1, 2010

Bruce! Thank you for all the info! I will take a look at this truck, when it comes in later tonight. I won't be able to spend too much time on it, because we usually have four mechanics for this building, and we are down two! One is out with kidney stones, and the other one bid on a day job at another building, cleaning out pallets from trailers! So its just me and one other mechanic....sorta!!! We are pushing 70 trucks each right now! I hope to find the data link issue, if not, my budy blown99 will get another one! LOL!

blown99 · July 1, 2010

You won't be able to pull any codes on the 1939 datalink with that ecm. The only only international engine ecms that put out service related info on the 1939 are the maxforce (ecm3) ecms. The ecm you are working with is programmed on the 1939 data link and communicates with other modules on the 1939 link, it just uses the 1708 to communicate to the service tools.

To check your 1939 data link measure voltage from the yellow wire at the ata connecotor to ground. Should be around 2.5vdc. Do the same to the green wire. should be around 2.5vdc. The two readings should never be the same. Take the two readings and add them up and they should equal 5 volts. Ex. one reading is 2.4vdc the other will be 2.6vdc. They add up to 5vdc. Which ever one has the higher voltage will be the can+ or high, which ever one is the lower voltage is can- or low. Disconnect the batteries, measure across the two can wires (yellow and green in the ata connector)and you should have 60 ohms. If you have 120 ohms then the terminating resistor at the end of the data link is missing or there is an open in the data link wire. I have seen very few issues with a 1939 data link. The ones I have seen tortured me as they were extremely intermittent and temperature dependent.

Also, currently the only software that works on the vt275 (that I am aware of) is service maxx. The latest version of master diagnostics does not work with the 275. It does not show all the faults, gives you unknown diag codes, unable to perform relative compression test and injector disable test, doesn't show any boost solenoid info, doesn't know what a MAF is.

Hope this helps

topfuel341 · July 1, 2010

Thank you! That should help me! I was not able to look at it tonight, but I should be able to tomorrow! I will look into the SBDT, maybe it was set on 1939? I know I had to select 1708 on my scanner, although I have'nt had any problems scanning any vt275's before. I will give everything you recomended, a try!

Thanks again!