Datalink Issue

Green Yellow is J1939.

 

Need Help. I had a guy at the truck stop do a quick weld job on my truck. his cable was a little frayed and when it came in to contact with my chain box my truck just shut off. It started back up just fine, but it wasn't till the guy left that i noticed that i am now getting a DATA LINK BROKEN message on my dash. ( Code: mid 140 sid 250 fmi 12). Also speedometer and tachometer and qualcomm not working either.
If any body has any ideas about whats wrong and how to fix it i would be grateful.
thanx

 

pablo
can u please send the picture of resistor as u mentioned under fuse box
because i had same problem
yesterday suddenly all dash board cluster work and stop and message comes check datalink broken
i have volvo d12 c model day cab year 2001

 

We have a DATA LINK BROKEN on a 2006 Volvo 670 with a Cummins ISX. He has NO gauges working except the fuel gauge. Speedometer doesn't work and the RPMs act like the engine is derated. His top speed is 62 and I only know that from his GPS. So I'm ASSUMING I need to hone in on the green-yellow 1939 pair, FIRST seeing if the resistance is correct at terminals C and D of the diagnostic connector. But I WON'T KNOW WHERE TO LOOK if If I find that the pair is broken. Sure, the pair goes to the ECU and through the bulkhead connector and finds its way under the dash where the terminating resistor is. BUT, where else is this pair going to be lurking? Under the cab at the transmission? ABS? The fuel system? No clue. .... I have a few days before the truck reaches me, so I'm hoping a few knowledgeable people will see this in time! .... And hoping it is the data link and as easy as finding the problem by the steering column or something. But I worry it'll be a shorted-out green wire somewhere and I won't have any idea how to find it. Maybe some kind of wiring diagram for 2006 670s would be helpful .............. and I also worry it'll be the OTHER data link and I'll NEVER find it. Hah.

 

Well, since I had inadequate information before seeing the truck, it turns out it wasn't the 1939 data link anyway. It was the 1587-1708 one. No harm done, since nobody bothered to answer anyway.

 

Where did you find the problem in the 1587 circuit?

 

What an adventure. Having the speedometer out, no tachometer, no oil-pressure or coolant gauge, AND to be governed at 1500 RPMs and 62 mph with a broken datalink. And who knew which datalink was broken? The driver didn't specify whether it was the J1939 or the J1708 & 1507. And whichever one was "broken," how to identify it in the wiring to even begin to trace the problem?

When the truck got to me, I tested the J1939 link, a twisted green-and-yellow pair of wires running all over. And the surprise was that it was fine. It read 60 ohms at the diagnostic connector when poking terminals F and G. Great, because I had spent 4 days researching that datalink. But the problem now was clearly with the OTHER data link and I didn't really know where to begin. Where was it? What colors were those wires? How many ohms should be at the diagnostic connector? I had only researched the 1939 beforehand.

So I read up as quickly as I could. I'm still not sure what resistance should be measured for the 1708-1587 data link, but it can be tested at terminals C & D at the diagnostic connector. There was no resistance -- in fact, there was total continuity, as if the two wires were crossed and became one wire. So that told me there was a short and that was why the data link was failing. BUT WHERE WAS THE SHORT?!

The instrument cluster showed a lot of MID 140 codes which made me think the cluster might've been bad (140 is the module ID for the cluster). So I pulled it and tested where the data link connected -- and by the way, this link is two black wires that are numbered 400 and 401 throughout the truck. Nope, no short coming from the instrument cluster. So I tested the light-control module. Then the brake module. And the climate module. And crawled under the truck looking for a cut in the harness. And poked around behind the fuse box. And disconnected the harness on the firewall, AKA bulkhead, testing the wires from the ECM to the bulkhead (no short there, so I knew it was between the bulkhead and the taillights!). ...

Because the driver had to load, I could only see the truck for an hour or two. I saw it twice and had no luck with the data-link problem and he drove off limping again. He was getting tired of mimicking a 62-mph Prime truck. Then I read in a post that somebody'd had problems with some former Qualcomm wiring interfering with a data link. I decided that the THIRD time I saw the truck, I would focus there: The qualcom wiring at the top of the cab, which I knew had been cut two years ago when we got the truck. It never gave us a problem after it was cut, but ----

As I researched "qualcomm data link problem" on google, I found a post with someone saying there was no way that corrosion in clipped qualcomm wiring could cause a short because corrosion causes resistance, not connectivity. Well, WRONG indeed. Two years after that cable was clipped, the copper wires at the roof of the cab became powdered up with the same green stuff that you find on car batteries. I suppose that's copper oxide and has poor but SEMI-CONDUCTIVE properties. And it was semi-conductive enough to connect (as in short) all of the clipped wires up there. And guess what. Qualcomms are wired straight into a truck's J1708 data link, meaning that data link had been exposed to the elements for two years.

So now all I had to do was trace the Qualcomm wiring to the data link. I ripped up the passenger floor, yanked out a kick panel, and voila: I found a plug between two Qualcomm wires and 400 and 401, the truck's data link. I unplugged it and walked around to start the truck. Bingo: The gauges worked, including the tachometer! Problem solved! Or so I thought!

I took a test drive and was crestfallen that the speedometer STILL wasn't working.

Well, thumbing through all of the codes after the test drive -- now that the modules could finally COMMUNICATE their faults to the instrument cluster -- I saw that the speed sensor was generating an active fault. So the sensor was bad -- it just happened to be bad at the same time the data link had been bad, so we had assumed they were a single problem. Went to Volvo in Indianapolis, bought a $38 speed sensor, and DONE! Both problems fixed.

 

My 2005 isx has green and yellow twisted pair, I have a Zf which works great after the air regulator was changed.

 

My cluster goes off when I start the truck and it trays to go on. It happens when the roads are wet snow and ice so far haven't been in rain yet. They flash and try to stay on then with the truck running they just come on. It shows J1708/J1587 after the cluster comes back on. This happened three times so far. I haven't had qualcom for 15 yrs. No wires on the roof and not sure were to look. Any help would be Nice. Thanks Len

 

Look under truck along the frame. Any white coming out from under wire harness wrap is suspicious. Cut the wrap carefully and look how is wires. I have had some wires corroded under wrap and insulation to the green/white powder.