06 6.0 no comm with any module but RCM

[aparise72]

I have an 06 6.0 with a runs rough cold concern. Customer had a new FICM installed and programmed. Now he brought it to me with a runs rough concern. I plugged the IDS into it and i cant communicated with the PCM, TCM, or IC. I'd love to figure out the issue with the running rough but I cant communicate with anything but the RCM. Any one seen this issue before? Thanks Andy

[Keith Browning]

I recommend going to section 418-00 of the WSM. The modules you listed that you cannot communicate with are all on the HS-CAN network. The RCM only uses the ISO 9141 communications network therefore it would not be affected my a HS-CAN fault. This is probably the best place to begin.

[aparise72]

I checked the hs-can circuits with the batteries disconnected between the PCM and the DLC and both test at .1 ohms resistance. I expected to see more than that. I am completely confused at this point.

[Aaron]

I would start unhooking modules one at a time to see which one is killing the network.

[aparise72]

I noticed something interesting when I disconnected the PCM to check the circuits. Them PCM was not mounted just kind of hanging there. I disconnected the trailer brake controller and found a rats nest of wiring in the dash under the TBC area....I think I found me a nightmare vehicle.

[batmantech]

Look on the bright side.. After this repair you will be completely familiar with communication networks!

[Brad Clayton]

I seem to remember a thread on here about the TBC module killing the network.

[Keith Browning]

Yes Brad, we did discuss this - any module can pull the network offline. I have had both TBC and clusters do this... I think the TBC is more common but if he is finding wiring issues he's probably better off following the pinpoint tests.

[Brad Clayton]

What's a pinpoint test?

[aparise72]

Well after disconnecting all modules from HS-CAN I tested the circuits to each other and to ground. The black wire has resistance to ground. I disconnected the connector under the underhood fuse block trying to find if my short was in the cab or under the hood. with conncector disconnected testing at the PCM connector I no longer had resistance to ground. I reconnected the connector and no have communication. So my communication isssue is probably in that connector.

 

Now I can't get the truck to fire. I have codes p0276 and p0472. So back to figuring this thing out. 

[aparise72]

Well I thought I figured out the communication issue and I was wrong. I had it communicating with the IC disconnected and monitored PIDs and all that happy fun stuff. Then I gave the IDS up for a little bit and once again no comm. I got the truck started by holding the throttle to the floor and it runs rough until it warms up then it smooths out and runs a little better. The story now has changed to he did his own head studs, EGR delete, and FICM. He took it somewhere else and had the FICM flashed. He said ran ok for a few days then started acting up. I have 48V M power and I have over 500psi ICP. No he doesn't want to go any farther into it so he is paying me for my time and taking it back and he is going to put injectors in it I am guessing.

 

My head hurts from this one. But I now know the HS-CAN wiring like the back of my hand.

[Keith Browning]

I hope that your head recovers. Have you taken the new advanced electronics course yet or have you done any serious diagnosis on the latest model year vehicles? The shit that is networked now is un-be-leavable! Window motors... door locks... holy shit! I hope you know how to use the oscilloscope because it is a must for diagnosing network issues now.

[aparise72]

I have not taken the advanced class yet but I took the online and I am not looking forward to the new ones. So far none of us here have had any issues with the newer cars.

 

Now I am only 28 so I can't say I miss the good old days but I like working on old cars, but the new ones pay the bills....most of the time.

[Jim Warman]

Sounds like your testing is getting piecemeal. I'd go back to square one - everything back to the way it was when I got it - and start by checking the terminating resistors through the DLC between pins 6 and 14. Your result here will determine your next step. Wiring needn't be the calamity we find it easy to convince ourselves of.

 

I hate to break it to anyone - this truck is NOT new - it's obsolete!!!

[Brad Clayton]

I would replace the TBC module.

[ktmlew]

I would replace the TBC module.

 

Well I would replace the cluster...    

[Bruce Amacker]

I'm thinking your HS-CAN is a J1939 bus.........

 

 

On IH's you can power the ECM by jumpering Bat+ through a fuse which does not power other modules on the truck.  At this point you connect the scan tool, it will show only the ECM on the J1939 bus, (where normally it shows all other modules too, like TCM, ABS, dash, aftermarket GPS, QualComm,  etc) jumper the starter, run all of the KOEO/KOER tests with the ignition key off and all other modules asleep.

 

On a Ford, can you power the PCM separately from other modules and communicate with it solely? This might save time by not unplugging a bunch of stuff.

 

Did you check your J1939 voltages and resistance, and verify they are correct? (probably 2.45v on the -, 2.55v on the +, and 60 ohms)

 

Just thinking out loud......

 

[Cetane]

Bruce,

 

  It is definitely not J1939.  We don't use that protocol for anything but the heavy stuff. You can power the ECU by itself but communication can be shaky without the right termination resistance.  If the high side of the bus is shorted to power or ground it won't matter any way unless you can use a jumper harness. Checking voltage and resistance is a reasonable next step but the fact that there is no communication with anything on the HSCAN bus already tells you there is a problem there.  I don't know where the other termination resistor is in the network but it wont be in any optional modules so your best bet is to start unplugging those first. Just my humble opinion.

[Keith Browning]

Correct - you will only find a "J1939" network in the medium duty trucks, not Super Duties which I guess this is what we are discussing here. Since I work on the entire Ford line I will add that  J1939 is in fact a Controller Area Network (CAN)The pinpoint tests for network diagnostics are pretty damn straight forward when it comes to circuits. As Jim mentioned, we need to keep things basic here and not make things more complicated than we need to. For anyone paying attention, IF YOU ARE USING THE VCM-2 it will still light up and look like it has power and is working (unlike the VCM-1) but if the 12-volt power to the DLC is not there the scan tool will not communicate with the vehicle and fuck with your head. Ask me how I know. Check the DLC power fuse first. If okay head to pinpoint test H in Section 418-00 of the WSM.

[mchan68]

Fan clutch??? Middle PCM connector........????

[aparise72]

I am honestly hoping this truck doesn't return. The owner does not want to spend any money on this truck and thinks we should just be able to look into our crystal ball and tell him what is wrong with it. That way he can take it back to his shop and fix it.

[Aaron]

In cases like those? The answer is always "replace the branch tube"

 

Yeah, I'm a dink

[Keith Browning]

I am honestly hoping this truck doesn't return. The owner does not want to spend any money on this truck and thinks we should just be able to look into our crystal ball and tell him what is wrong with it. That way he can take it back to his shop and fix it.

 

 

The ironic thing about this scenario is that usually to diagnose this particular concern you have to fix the concern

[Aaron]

 

I am honestly hoping this truck doesn't return. The owner does not want to spend any money on this truck and thinks we should just be able to look into our crystal ball and tell him what is wrong with it. That way he can take it back to his shop and fix it.

The ironic thing about this scenario is that usually to diagnose this particular concern you have to fix the concern

Ain't that the truth. Well, diagnosis is gonna be 3 hours. How much is the repair?Nothing.What a hell of a deal! Lol.