DLC 4&5 Voltage

Brian Instructor Ohio Posted   Latest   Edited  

Hello every one,

I am trying to collect a fair amount of data samples to get a average voltage between Pins 4 and 5 at the DLC KOEO and KOER. I usually test between these pins when diagnosing problems as part of my routine.

In an attempt to teach this method I would like more information than I can gather on my own. I am willing to share the data collected here. Let me know if you have any questions! I will add more manufactures if needed, select GM if not listed and make a note and I will adjust form.

Thanks in advance for any contributions.

docs​.​google​.​com/forms/d/e/1FAI…

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Hollis Technician
Colorado
Hollis Default
   

Do mean something like this ?

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Brian Instructor
Ohio
Brian Default
 

Yes!

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Hollis Technician
Colorado
Hollis Default
 

Should I choose 'Option 10' for the make? There's not a choice for Subaru. KOEO is 0.45 mv. No activity on CAN.

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Brian Instructor
Ohio
Brian Default
 

yes I will adjust

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Brian Instructor
Ohio
Brian Default
 

Subaru added,

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Hollis Technician
Colorado
Hollis Default
 

Submitted. See what you think.

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Bernie Engineer
California
Bernie Default
 

Well ideally and from a how it should work on from the vehicle-side: 1) pin 4 is chassis ground (for sourcing power to external equipment), and pin 5 is signal ground (for communication lines). 2) There could be non-zero voltage readings between pins 4+5, but it is going to depend on hardware equipment installed in the vehicle (ECU options, etc) and the operational state of the communication…

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Brian Instructor
Ohio
Brian Default
 

Hello Bernie, I am mainly curious to see if similarities will arise across specific makes and models. I am expecting that to be the case. I have been doing a DLC quick testing seminar and thought it would be helpful to back up what I am saying with some data collected by some one other than myself. If a specific model has a few "known good" values of 0.150V and another model has .005V I am…

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Bernie Engineer
California
Bernie Default
 

Brian, totally get where you are coming from, and dig the effort. Keep in mind that measurements should be done directly off the face of the DLC, otherwise the measured value may get altered by the presence of any active components that are inside any attached external test equipment. I know accessing the DLC face is a pain, but for good measurements its necessary. Again, totally like your…

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Brian Instructor
Ohio
Brian Default
 

Bernie, I see what you are saying, and have thought a little about the differences in testing methods, possibly even the test leads being dirty causing incorrect readings due to we are looking for differences <1 V, or using a BOB. If others care to participate I hope to see if trends will appear early on. We will see what happens! Thank you for your input.

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Bob Engineer
Michigan
Bob Default
 

Hi All, Bernie is spot on. As I have found in the field, different OEMs have different connectivity to these pins, even between models. Also, many tools connect these two pins together internally, which would tend to negate any "open circuit" readings. Cheers, Bob

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Brian Instructor
Ohio
Brian Default
 

Hi Bob, I don not think that I was clear about the "why" of doing this. I am aware that many tools, mainly after market, connect or bridge 4 & 5 . I know that differences exist between models and manufactures as well. I am gathering this information due to the fact of going through my own diagnosis of vehicles at times I get a reading between 4 and 5 that seems high based on my experience…

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David Mobile Technician
California
David Default
 

Bernie, isn't the use of a DLC BOB the same as the face of the DLC? Davie

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James Diagnostician
Georgia
James Default
 

Time and scheduling permitting I will try some of this tomorrow

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Hollis Technician
Colorado
Hollis Default
 

Have you seen this site, ScanShare ? I don't know if it would have any of the data you're looking for, might be worth a shot. scanshare​.​io/Home/Register

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Brian Instructor
Ohio
Brian Default
   

I have not seen that site. I am taking a look at it now. Trying the $5 Sub

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Geoff Diagnostician
Hawaii
Geoff Default
 

Oh, wow, you hadn't seen ScanShare.....If I remember the story correctly Jim Wilson's son wrote the code for the site so Jim could share info with other techs and teach Data analysis better. He's an instructor with Standard now.

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Brian Instructor
Ohio
Brian Default
 

I guess I am just slow to the party! Pretty cool site!

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Geoff Diagnostician
Hawaii
Geoff Default
 

It's great for educators and long-distance tech assist. You can upload from many different tools, and then anybody who reviews the data can customize the list any way they want. And the best part, since it is web browser based, it works on any Mac too. Even my old one that won't play videos for THIS web site. :-)

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Brian Instructor
Ohio
Brian Default
 

UPDATE Please convert reading to Volts. IE 6.2mV = 0.0062 V Here are the results so far. Who ever had posted the 96 Suburban I am assuming readings are in mV and will change to volts. Thanks for everyone who is taking the time to add! If nothing else we will all be familiar with what to expect between 4&5.

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