Ford Network Nightmare

Todd Mobile Technician Alberta Posted   Latest   Edited   Bounty  
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Network Communications
2017 Ford F-150 XL 3.5L (8 Flex) 6-spd (6R80)
Power Steering Assist Affected
Multiple Instrument Cluster Warnings And Chimes

Clean truck presented itself with Christmas Tree Cluster, power steering inhibited.

Network test with IDS revealed ALL modules on the HS2 CAN wink out simultaneously, resulting in the symptoms the customer experiences. You can run the network test and all the CAN2 modules will fail, then run it again and they will all be present.

This is a pretty base vehicle, not even a Ecoboost, first one without the turbos that I have seen.

Anyway, not a lot of modules to worry about.

Considering the fascinating behaviour of the network in question and the fact that I had absolutely no direction, I decided to scope the problem network.

Keep in mind that this vehicle has 4 networks, terminating in a “Gateway” that connects to the DLC.

I have not completed testing and thought I would run this by the group in case anyone has encountered this issue before.

First is a pic of the network as well as the Pico capture is with the Gateway intact, (it was exactly the same with the gateway removed)

It appears that the network just goes still, like something told it to shut up, then continues on its way.

You will note that it does not go low, like a short to ground nor does it go high, like a short to voltage.

There is a slight dip in the CAN voltage by a 100mv or so periodically.

Nor does it go crazy, like noise or a node on the fritz.

Sorry, these are long time base captures done with a 3000 series so they are a little pointy when you zoom.

Please have a look and give me your thoughts, thanks

Oh, BTW, ignore the channel labelling.

Channel B Red is CAN +

Channel A is CAN -

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Interesting
Dmitriy Analyst
Ontario
Dmitriy Default
 

Todd, it looks like no one has encountered something like this. There seems to be some attempted activity on the line during the failure, but the sample rate of the capture does not allow to see it well. Is this happening regularly with KOEO? If so, you might try to capture the failure with timebase at 2 seconds and get a clearer picture. Otherwise, you can try to disconnect/unpower modules on…

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Todd Mobile Technician
Alberta
Todd Default
 

Thanks for your reply. I will take another shot of it at a shorter time base. Then we can look at it a little closer.

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Caleb Diagnostician
Indiana
Caleb Default
   

Im not even close to Dmitriy expertise on CAN but ill throw in a few thoughts. Looking at SI HS1 and HS2 are both hardwired to the DLC, only HS3 and MS CAN are not linked directly to the DLC. SI also says that HS3 and MS CAN comm with the scanner via HS2. The Steering Column Control Module and the Gateway house the resistors for HS2. Have you checked HS2 resistance at pins 3&11? I see where…

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Todd Mobile Technician
Alberta
Todd Default
 

Thanks for this. Could it be that perhaps either HS3 or MS CAN could be the cause of the issue on HS2? It is something that I will have a good look at and post.

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Randy Diagnostician
Colorado
Randy Default
 

Best guess is can lines are shorted together but I would want more information like what DTCs are set in what modules including all networks and then what modules are present when bus is active and are any missing. when the symptom occurs, I would request something with the scan tool to see if activity is present. Need more data from scan tool.

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Manuel Diagnostician
New Jersey
Manuel Default
   

Fords way of troubleshooting this is kinda lousy. They’ll have you pull fuses to isolate modules but it doesn’t really work if you have a wiring problem. Common culprit for me is peer steering. Check wiring to connector for heat damage or stretching and proper oem routing and try to disconnect module and revisit symptoms.

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Todd Mobile Technician
Alberta
Todd Default
 

Hi Manuel, have you ever seen a PSCM make the network rest? And, I must admit I have never seen the result of CAN lines shorted together. Would it cause the result we see in the capture?

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Todd Mobile Technician
Alberta
Todd Update
 

Thanks to all for their replies. I will get some shorter time base captures so as to have a better look at the network and as Radny asked,I will grab some more information with the scan tool. We will get to the bottom of this.

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Glenn Owner/Technician
Texas
Glenn Default
 

Is there any past collision history. The front steering could have been “shocked” during a collision event and it would disrupt the EPS unit.

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Todd Mobile Technician
Alberta
Todd Default
 

Finally got back to the vehicle in question. The POS never acted up for me any time that I was present since I posted. It has never left the care of the shop that it was brought to. I do, however, have a capture of the HS2 network taken while i was shorting it together. As some had stated, the 2 CAN legs stay at 2.5 Volts and you can see modules 'fighting through" as you can see some…

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Chris Technical Support Specialist
New York
Chris Default
 

diag​.​net/file/fdi4l73r8… ​ When I see saw tooth patterns like this I typically find a module is causing the issue. You could disconnect the gateway and monitor each network individually to try to isolate what network is causing issues. Ford does make a breakout box for this. 164-R9852 - Gateway Module Breakout Box (service-solutions​.​com) If modules get bad enough…

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Dmitriy Analyst
Ontario
Dmitriy Default
 

Chris, this is probably just the result of 1MS/s sample rate (viewing 500Kbit/s signal). Todd, what I find interesting is that there is one or more modules on your network that use marginally OK signalling levels 1.75 – 3.1V: diag​.​net/file/f61exwop5… ​ The others use the standard 1.5 – 3.5V signalling. Not sure what to make of it. Very hard to diagnose anything when it does…

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Al Technician
Ontario
Al Default
 

I ran into a similar problem 2017 F-150 It turned out to have a bad connection at the gateway module. Terminating resistors are located in the Steering Colum Control Module and the Gateway module. Back probe the network and check for 60 Ohms. I was loosing the terminating resistor in the gateway module giving me 120 Ohms. The vehicle I was working on also had broken Can wires in the right side…

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