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Torque » Torque OBD ECU Scanner » Torque Discussion / Ideas » Inside a cheap eBay OBD2 adapter - Ford connection problem

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Author Topic: Inside a cheap eBay OBD2 adapter - Ford connection problem
Monty_
Member
Posts: 21
Post Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 2, 2012 (GMT)

Greetings to all,

I bought a cheap eBay OBD2 adapter and sure enough it would not connect with my Ford Taurus using Torque Pro. Frustrated, I took it apart to see what in it and how it was built, and here it is.

To open the case, you remove the plastic label which will reveal 4 screws which secures the top/bottom clam shell. Pretty simple.

The electronics is on a double-sided circuit board and generally very well constructed using quality components, presumably because components are machine loaded and wave soldered in an automated process.

Where it falls apart is the wiring to the OBD2 connector which is hand-soldered. There was a patch of solder splatter and a length of unmelted solder to one of the pins, but there were no open or short circuits, just very ugly. I cleaned it up and reassembled the unit but still no joy with connecting to the ECU.

piemmm
Administrator
Posts: 6082
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 2, 2012 (GMT)

Hi

I’m not 100% sure if your taurus is OBD2 compliant – what year was it built and fuel type?

For those types of adatpers that don’t work on fords (that are OBD2 compliant), there is a mod you can do to fix them – another kind person posted this information on the forum

http://torque-bhp.com/forums/?wpforumaction=viewtopic&t=1571.0

Monty_
Member
Posts: 21
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 2, 2012 (GMT)

Thank you so much, Ian! I will go through the modification information and hopefully get it to work. Will also report back.

My Taurus is a 2003 Canadian model with a 24V 3.0L V6 Duratec. I do believe it is OBD2 compliant.

Monty_
Member
Posts: 21
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 2, 2012 (GMT)

I am happy to report that the modification absolutely works, and now I’m a happy camper using a cheap eBay dongle to monitor a 2003 Ford Taurus via Torque Pro.

The modification to the dongle Ian linked to above is for a USB version (mine is Bluetooth) so the circuit board is somewhat different, but the circuit modification involved is the same. Please note that this modification is for boards marked as ELM327M Ver. 1.4a; I don’t know if it would work on other versions.

The modification involves cutting a track leading to a transistor pad to release it from its origin and reconnecting it to circuit ground – the ground in my case was taken at the absent USB wiring holes. This is the reason why some Bluetooth dongles have a small plastic grommet to cover the USB cable exit.

Many thanks once again to Ian and prokusp for pointing me to the right direction. Hopefully others can also make use of this information to get their dongle working.

cws0505
Member
Posts: 4
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 2, 2012 (GMT)

Monty,
Thanks for the pics. Mine is the same adapter as yours. I did have one question, between the T2 and T5 I see some scratching and was wondering what you had to do there. Did you scratch between the two in a straight line or hook like red line or did you desloder the leg on T5 to hook up the wire like in “a”. Its just kinda tough to see what you “cut” on the board. I wanna try this so mine will hopefully work right.
Thanks for your help!

Monty_
Member
Posts: 21
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 2, 2012 (GMT)

It’s a bit tricky and here’s what I did:

The transistor pad on your picture marked “A” is connected to the center pad above-left of the R52 marking, and also connected to R61. You can verify this with an Ohm meter.

The circuit trace that connects these components is a very thin track that runs under the black bodies of the two transistors T2 and T5, and between the black bodies of T2 and T5 is where I cut the track (as indicated by your red line, but the circuit trace is very hard to see).

I just scraped between the transistor bodies and tested it with an Ohm meter to make sure continuity was broken, then connected the relieved transistor pad to ground.

My description isn’t great but hopefully you get the idea. :-)

cws0505
Member
Posts: 4
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 2, 2012 (GMT)

I understand, I think lol So all I really need to do is to scrape between the two transistors, then solder the wire correct?
The problem I’m having is not connecting to the ECU. Is that the same problem you were having? ELM327 is working fine on my friends Acura but gives me that error on my ’99 Ford Ranger.
Thanks again for the help!

Monty_
Member
Posts: 21
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 3, 2012 (GMT)

Correct on all counts, just be careful when cutting/scraping between the transistors to remove the copper connection.

I haven’t tried mine on another vehicle yet, but given the widespread reported similarities, I suspect mine will work on other brands – will try and report when I get a chance.

cws0505
Member
Posts: 4
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 3, 2012 (GMT)

Thanks again for the help Monty! I just finished mine but havent tested it yet. I’ll let ya know in the morning if I did it right lol Thanks a ton!

Monty_
Member
Posts: 21
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 3, 2012 (GMT)

I hope it works for you as it did for me!

Given the amount of space in the enclosure, I also thought about putting in a power switch to interrupt pin-16 (+12V) so the adapter can remain in the car without draining the battery. Might be even better to wire pin-16 to post ignition.

Monty_
Member
Posts: 21
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 4, 2012 (GMT)

I don’t know if this is going to help anyone; I came across another Chinese OBD2 dongle which claims to work on all protocols as explained below:

The item is here:
http://www.ebay.com.sg/itm/OBDII-OBD2-diagnostic-327-1-4-wireless-Bluetooth-/280668420438#ht_4801wt_906

Looks like there are many permutations of the same basic product.

Monty_
Member
Posts: 21
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 4, 2012 (GMT)

Okay, I added a power interrupter to Pin-16 through a SPST toggle switch. I should have also relocated the red (power indicator) LED because of the orientation of the OBD2 socket in my car; next time.

denis1304
Member
Posts: 3
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 4, 2012 (GMT)

Hello!
I also have ELM 327 BT dongle with PCB board like right one from Monty_ picture, but there is not much at the back side of the PCB… it looks like http://imageshack.us/photo/my-images/198/20110803131410.jpg/
I have tested it on my Ford Mondeo TDCI 2002 diesel (Europe model) and it is not working with Torque PRO app on my mobile phone (dongle paired on Bluetooth but will not connect to Torque Pro).
Since I’m not expert in electronic I don’t know if it can be modified to work like you can with other versions.
Do someone know how to modified it?

Thanks

cws0505
Member
Posts: 4
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 4, 2012 (GMT)

Monty….You are the best! First off I want to say thank you for explaining things to me. Second, IT WORKS!!! Third, I like that switch…
Last night I tried my modded ELM327 in a Chevy Van and it worked fine. When I got home I tried it on my Ranger and works perfect!! One more tip for anybody wanting to try this…make sure you have a steady hand and a small soldering iron lol The connection is VERY small. But it is really simple to do with some patience. Also my red ‘cut’ line above does not need the hook on it, just use a razor blade and cut into the board a bit and as Monty stated check with a ohmmeter.
Monty, again, thank you very much!
Denis, I’m not sure, which model that is but on the opposite side of the board look for the version #. I’m sure someone could will chime in and help you mod it.

Monty_
Member
Posts: 21
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 4, 2012 (GMT)

CWS, really glad it worked for you too. This confirms the mod. is legitimate at least for the particular model we have.

Here’s a picture of the power switch wiring – pretty basic but works. I thought about tapping a post-ignition point from the car but didn’t want the dongle tethered to it.

Dennis, there are apparently many variations of the same design that it’s difficult to say what your problem is, especially when schematics are not available.

The problem with my unit was a printed circuit board layout error – a pad that was supposed to go to ground was routed elsewhere. The error may have originated in the schematic. If that’s the case, it’s entirely possible that the same error has migrated to every permutation of the same dongle including yours.

Unfortunately there isn’t an easy way to verify this as it requires cross-checking of every unit. However, you can at least check if one leg of transistors Q3 and Q4 near the input connector is really connected to ground. Your picture shows it connected to an apparent ground plane, but it might not be connected to system ground.

This is just a stab at the problem from looking at your picture, Dennis, and probably worth checking if you have an Ohm meter (VOM) handy.

denis1304
Member
Posts: 3
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 4, 2012 (GMT)

Q3 and Q4 are at the back right? And witch “leg” should go to ground a,b,c,d,e,f and where is ground?

Thank you for your help… and I know you can’t guaranty result

Denis

Monty_
Member
Posts: 21
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 4, 2012 (GMT)

Dennis, that would be components “e” and “f” indicated in your picture, and their left leg as viewed in the photo appears connect to ground – that would be the patch of copper the legs are soldered to.

There are plated-through holes to connect the two patches to the other side of the board and should eventually snake its way to the main patch of ground plane, that would be the mass of copper everywhere on the board.

If in doubt, test for continuity of the two transistor legs to OBD2 connector pins 4 and 5 which is connected to vehicle ground. These pins should appear longer than the others when viewed from the front presumably because they will mate with vehicle ground first, when inserted.

denis1304
Member
Posts: 3
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 4, 2012 (GMT)

Maybe I was not clear with my photo… a,b,c,d,e,f, are legs for component Q3 and Q4… so witch leg (a,b,c,d,e,f,) should go to the ground?
Hope you know what I mean…

Thank you, Denis

https://www.dropbox.com/gallery/48295609/1/obd2?h=ac3247 these are photos of my dongle

Monty_
Member
Posts: 21
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 4, 2012 (GMT)

Dennis, the two red arrows point to the transistor legs which (apparently) should connect to ground.

The three blue(ish) arrows point to (apparent) ground planes.

If you have an Ohm meter, test to see if all five arrow-head points are connected together.

Sorry I’m unable to be more clear with a better description.

Edit: On the blue arrow heads, you need to scrape off the green solder mask to reveal the copper underneath to test for continuity.

Mario
Member
Posts: 4
Post Re: Inside a cheap eBay OBD2 adapter - Ford connection problem
on: February 8, 2012 (GMT)

Quote from Monty_ on February 4, 2012
If you have an Ohm meter, test to see if all five arrow-head points are connected together.

I have the exact same “china” OBD Bluetooth adapter. All the arrows have conductivity with ground together.

Also, I’ve found Q3 & Q4 on this board are linked to Pins 7 & 15 on the OBD Port… so they can’t be related to the PWM protocol problem unfortunately.

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