Parasitic draw testing , need some confirmation

Caleb Technician Indiana Posted   Latest   Edited  
Updated
Electrical
2012 Ford F-250 Super Duty XLT 6.7L (T) 6-spd (6R140)
No Codes
Sometimes Weak Battery

Have this 2012 F 250 pickup with a 250 milliamp draw after sitting for at least an hour and also after it sat all night. Hood switch closed and all door latches latched an locked with fob and fob out of range. I found a 3 millivolt drop on fuse 11 which is a 10 amp in the BCM . The millivolt to milliamp conversion was close to my draw using the power probe conversion chart. I have attached a diagram and pinout. Not sure how to put captions so sorry if it makes it a little confusing to follow. Also would like to know how to take screen shot of wiring diagram on my laptop and then attach the screenshot here?? Fuse 11 powers only the IPC. When i pull the fuse the draw instantly drops below 50 milliamps and stays there when monitoring for over an hour. This is the only power input and there is only one ground. I access the IPC and begin testing , keep in mind the truck is still in its draw test state. I can light my 750 milliamp test light on the ground and only has 180 mv drop backprobing pin 22 . B+ pin 6 is good when loaded no drop backprobed. No issues pin 5 this truck does not have hill descent. Pin 9 Traction control switch input cycles 0-12 v when pressed. Pin 10 this truck doesnt have fuel tank select switch. Pin 11 0v for message center switch return/grd when pressed or not pressed ok. Pin 12 fuel level sensor 3.5 volts backprobed, 0v IPC unplugged. Pin 13 no #2 fuel level sensor. Pins 16 an 17 4wd illumination unplug 4wd switch no change in draw. Pin 20 park switch sense cycles 0-12v when pulling on shifter. Pin 24 message center rest 4.5v backprobed and voltage drop accordingly when cycling message center buttons. Unplug message center switch no change in draw. Pin 25 0v for fuel level sensor grd backprobed. Pin 26 again truck not equipped with second tank. IPC is on High Speed CAN{see attached network config chart}. Truck does not have an APIM so BCM is the only gateway. With IPC connected both pins 6 an 14 rest/sleep at 600mv. IPC disconnected pins 6 an 14 drop to 0 volts. Resistance of pins 6 an 14 is always 60 IPC plugged or unplugged. Medium speed CAN pins 3 and 11 rest/sleep at 500mv but as long as IPC is unplugged there is no draw so i guess i really dont care about the 500mv?? The truck has the audio control module/radio removed for customer religous reasons. Thought maybe IPC is looking for the radio but find it hard to believe the IPC would be the only one and they are on different networks. I did not check for codes in the IPC which is my mistake. Unplugging IPC and giving it power and ground at pins 6 an 22 it pulls 300 milliamps constant but has a couple guage needles lit up that im assuming wont shut down because CAN isnt there to tell the needle lights to shut off?? Anyway this is a really long write up and im sure im overthinking and just needs an IPC. Thanks so much for reading and all input is welcomed. Just want to make sure before i call the IPC!

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Mario Diagnostician
Florida
Mario Default
 

I think your on the right track. If your doubting the ground voltage drop, provide a redundant ground. I'd still attempt to grab codes, surprisingly it may just give you a heads up on a circuit issue. But all signs point to cluster according to your test results

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Caleb Technician
Indiana
Caleb Default
 

Thanks for your input Mario. In this case I guess I'm not worried about the 180 mv grd drop because it's a very small wire an the test light is 750 milliamps which is a pretty decent load for this grd I believe??

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Phillip Diagnostician
Alaska
Phillip Default
 

If u want to do a screen shot from your computer it's window key + print screen key.

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Rusty Owner/Technician
Massachusetts
Rusty Default
 

Make sure the park position sensor is working correctly. I called a cluster as the cause of a draw on an F150. Unplugging the IPC brought the draw down to an acceptable range. A new cluster didn’t Fissit and we found the park sensor was faulty and keeping the IPC awake.

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Rick Diagnostician
Texas
Rick Default
 

Rusty, I have seen that before as well. A quick test for this is watching the PRNDL display in the instrument cluster. If you put in park from any gear and the P isn't lighting up then the park position sensor isn't working correctly. A Ford engineer told me it is the number one cause of instrument cluster draws causing unneeded cluster replacement at the dealer which I suspect is due to

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Caleb Technician
Indiana
Caleb Default
 

Thanks Rusty. As I noted the shifter park sense switch toggles 0 -12 v when pulling shifter. Also the P in the PRNDL on the cluster is highlighted when in park with the truck running. I also a 13 F150 with the same issue as you....i also got burned on that on. This time I think we are good.

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Saifullah Diagnostician
Ontario
Saifullah Default
 

I had an escape with the same amount of draw. It ended up being a steering wheel button sticking causing the IPC to stay awake. Does the draw go up and down every 20 minutes?

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Caleb Technician
Indiana
Caleb Default
 

Thanks Saifullah. As I noted the message center voltage toggles accordingly when pressing the buttons an with the switch unplugged there is no change in the draw. Also the message center works correctly truck running.

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Brin Diagnostician
Florida
Brin Default
 

You're not over thinking. You're trying ro accurately pinpoint the cauae of the concern. We can all appreciate that. I'm not sure that I'm following every detail so bare with me. Have you scoped the communication bus? Is there any bus activity maybe causing the IPC to stay awake? If you just jumped power and ground to the cluster with everything else unplugged, and the draw was still

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Caleb Technician
Indiana
Caleb Default
 

Thanks Brin. I have attached photos of scope on high speed Can+ an and high speed CAN- at 600 mV with IPC plugged in. IPC unplugged scope goes to 0v on both CAN lines. There is no activity on the bus with IPC unplugged and no draw when using the amp clamp around grd cables at battery. Medium speed CAN is always "resting " at 500 mV on both lines IPC plugged in or not plugged in. I guess I don't

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Brin Diagnostician
Florida
Brin Default
 

I mentioned having a similar diagnostic last year. I hate doing anything that gives the appearance of self promotion but I thought you might appreciate my battle. youtu​.​be/Q_kJJTIZddc

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Thomas Diagnostician
Florida
Thomas Default
 

What did you end up charging for that job in coconuts....

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Saifullah Diagnostician
Ontario
Saifullah Default
 

Lol

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Caleb Technician
Indiana
Caleb Default
 

Yes thanks Brin. I have watched this video in the past an it was definitely in the back of my head lol!

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John Instructor
Pennsylvania
John Default
 

First question was how did you measure the draw initially? Did you use a low amps probe or the current settings in your multimeter? The next thing to consider is Kirchhoff's current law, "all of the current entering any one point equals all of the current leaving it". Instead of doing a group of voltage tests, measure the current. A low amps probe if you have one makes this easy. Since we know

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Brin Diagnostician
Florida
Brin Default
   

That's perfect John.

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Caleb Technician
Indiana
Caleb Default
 

Thanks John so I used low amp clamp with scope around negative cable to check draw. After 1 hr rezero clamp an still 250 -300 milliamps. Then v drop fuses till #11 in BCM shows 3 mv drop. Remove fuse draw gone. Install fuse loop an put clamp there . 250ma draw . Unplug IPC draw is gone.

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John Instructor
Pennsylvania
John Default
 

All good so far. What a tech needs to do at this point is measure the current going into and out of the component that has the draw associated to it. You were faced with the problem of proving if the draw was internal to or external of the instrument cluster. A quick measurement of the ground circuit would confirm that. With the instrument cluster the main concern then switches to the thought

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Caleb Technician
Indiana
Caleb Default
 

Thanks John. As you can read in my original post I believe I eliminated all the possible externals. Also as I said I disconnected the IPC and powered up jus the power an grds to the IPC. The draw was still there......

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Darryl Technician
New York
Darryl Default
   

Try doing network test if your scanner can​.​ Based upon what you did sounds like ipc

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Eric Owner/Technician
Wisconsin
Eric Default
 

Caleb, to do a screen capture on a Windows computer, arrange the screen the way you want it and then press the Print Screen key. This key is usually in the upper right area of the keyboard and is labeled as PRNT SCRN or PRTSC or something similar, it varies depending on computer manufacturer. Then open the Paint program and paste into it. Then you can use the select and crop features to remove

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Geoff Diagnostician
Hawaii
Geoff Default
 

I had to add Paint to my "task bar". I could never remember how to find it otherwise.

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Eric Owner/Technician
Wisconsin
Eric Default
 

Press and release the Windows key then start typing the name of the program you are looking for, in this case, "Paint".

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Chris Technical Support Specialist
New York
Chris Default
 

There us also a snipping tool in windows that is easy to use. diag​.​net/file/f2u0zlmuq… Click new, Outline what you want to save, you can select copy to add it to the clipboard or save the file.

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Caleb Technician
Indiana
Caleb Default
 

thanks Chris. I will give it a shot.

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Caleb Technician
Indiana
Caleb Update
 

Thanks everyone for all the input. The new cluster from Ford is on my bench. Just waiting for the vehicle to return. In the meantime if i get time tommorrow I will power it up on the bench an see if there is a difference in the draw.

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Caleb Technician
Indiana
Caleb Update
 

Alright guys......so this is a bittersweet ending. Plugged inthe new IPC with identical draw 300 ma. High Speed Can pins 6 an 14 still stuck at 600mv. Medium Speed CAN pins 3 an 11 still stuck at 500mv. So I started all over. Full code scan no codes. Double checked every input to the IPC again even ones truck doesn't have but there is a wire in the connector. All ok. As I said in original post

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Saifullah Diagnostician
Ontario
Saifullah Default
 

Amazing work!! Great job!!

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Chris Technical Support Specialist
New York
Chris Default
 

Do you know what pins those wires connect? are they the two connectors from the radio that are connected??? I have never seen that jumper before,

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Caleb Technician
Indiana
Caleb Default
   

Hey Chris not sure I understand your question but i think I do. So basically all the connectors for the radio plugged into this jumper an went behind the IP tie bar above the HVAC box. So yes it caused Medium Speed CAN to go to whatever component was installed. And yes neither have I. I tried a Google search of the part No# on the tag but nothing came up.

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