No data or codes with Snap-on scanner MT2500

Tiny
BEALE120
  • MEMBER
  • 1993 FORD THUNDERBIRD
  • 3.8L
  • V6
  • RWD
  • AUTOMATIC
  • 57,000 MILES
Hello first I want to thank you for taking this question.

I have a 93 Ford Thunderbird Supercoupe 3.8. When I connect my Snap-on MT2500 scanner it will not receive any data and codes from the data link connector (under hood). The car can do functional tests with the scanner. I have tested all the pins at the data link connector. Here are my voltage readings on the data lines KOEO.

Bus+@ 4.88V
Bus-@ 300MV (voltage drop).

Do these voltages sound correct? I have snap-on booklet and it says Bus + should be 5V and Bus- 0V.
I have tried two of the same scanners and they both have the same result. I did also enter the VIN correctly. Please help!

I appreciate it.
Eric
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Saturday, April 9th, 2016 AT 1:55 PM

9 Replies

Tiny
HMAC300
  • EXPERT
Try doing test with an volt /ohm meter this is OBD1 not OBD2 see pic on where to put things to watch flashing light then you can come back to site to see listing of oOBD1 codes for what area to check
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Saturday, April 9th, 2016 AT 2:53 PM
Tiny
BEALE120
  • MEMBER
Yes I'm able to do that. I've tried that already. I'm able to get flash codes from the instrument cluster. This shows that a lot of the wires are functional. I don't have any driveability problems right now. My problem is no data or codes with my scanner. Those bus wire voltages do those seem right?

Thanks
Eric
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Saturday, April 9th, 2016 AT 3:24 PM
Tiny
HMAC300
  • EXPERT
I didn't think obd1 had bus connections as I know it. But you are reading damn close to 5 volts and you are reading milli volts on negative side so I really wouldn't worry about it. Besides things like poor grounds /poor battery connection can alter what it is supposed to be besides age of car.
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Saturday, April 9th, 2016 AT 4:55 PM
Tiny
BEALE120
  • MEMBER
Again, I appreciate your time and your fast response. I have diagrams that show it has communication lines Bus+ and Bus- pins 1 and 3 of data link connector. I'm surprised that I have no communication with the scanner being that the wires test fine. Once again when I have the scanner connected I'm able to do functional tests with the scanner. That tells me a lot of the wiring integrity even though I tested all of the wires and they are within spec.
I did talk to snap on and they can't figure it out and we went over everything for an hour on the phone. As far as poor grounds I even bypassed the ground wire from the data link connector and still have the same results. I own a 93 GM truck and a 93 Jeep Cherokee and I'm able to receive data and codes from the scanner. Do you or anyone you know have any ideas? I'll do what ever is necessary!

Thanks Eric
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Saturday, April 9th, 2016 AT 7:04 PM
Tiny
HMAC300
  • EXPERT
If you can do it on other vehicles but not the one then it's a connection problem either at aldl or scanner. It may need new connectors in aldl or cleaned, try spraying the one car with brake or choke cleaner then smearing some dielectric grease on it to see if that helps. Other than that I don't know what to tell you.
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Sunday, April 10th, 2016 AT 8:27 AM
Tiny
BEALE120
  • MEMBER
I'll try that. Is there anyone else on this website that knows about Bus communications that could help me?

Thanks
Eric
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Sunday, April 10th, 2016 AT 9:03 AM
Tiny
HMAC300
  • EXPERT
Send this to mike@2carpros he can put someone who may be able to give a better answer, but usually if it works on other cars and not one its a connection unless there is a fuse for it.
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Sunday, April 10th, 2016 AT 9:19 AM
Tiny
BEALE120
  • MEMBER
Thanks. I appreciate it. I'll get in touch with Mike then.
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Sunday, April 10th, 2016 AT 2:39 PM
Tiny
BEALE120
  • MEMBER
Hey HMAC300,

I wanted to let you know real quick that I'm now able to receive data and codes from the car. What it was that the Ford adapter must not of been connected the entire way with the Data Link connector. Thanks for all of your help.
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Sunday, April 10th, 2016 AT 5:53 PM

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