bad diagnostic port
#1
10-07-2011 | 10:50 PM
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bad diagnostic port
cant get my code reader to work!! i have a 98 blazer with the check engine light on. i tried plugging in a maxiscan ms509 and it cant connect, i also tried a little trip recorder and it couldnt connect either. cig lighter works fine and i have power at number 16 pin, ground at 4 pin and 3xx ohms at 5 pin. might have the readings for pin 4 and 5 mixed up tho. also the tranmission is shot, 3rd and 4rth wont work. could this be causing the light
#2
10-08-2011 | 02:32 PM
Starting Member
Joined: Dec 2008
Posts: 176
From: Wheeling, IL
Hello Bob,
Not sure about your engine light but I have attached some Data link Connection Info.
What about number 2 or 9?
Mark K
Here is a small Trouble shooting guide for the data Link.
Check Fuse #7 also. The cigarette Lighter is on fuse #2.
The data link is on fuse #7
Good Luck maybe it is something simple.
Mark
Not sure about your engine light but I have attached some Data link Connection Info.
What about number 2 or 9?
Mark K
Here is a small Trouble shooting guide for the data Link.
Check Fuse #7 also. The cigarette Lighter is on fuse #2.
The data link is on fuse #7
Good Luck maybe it is something simple.
Mark
#3
10-08-2011 | 07:45 PM
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Posts: 23
what should i see at 9? 12v or ground? havent checked it yet. il check the fuse but i think im good seeing as i have power at 16
#4
10-09-2011 | 07:14 AM
Starting Member
Joined: Dec 2008
Posts: 176
From: Wheeling, IL
Hello Bob,
With the engine on, at the data link Position 9 should have a small
amount of power. Not sure how much. Probably very little since
it is coming from a computer and going into a OB2 computer
to read info. The PPL(Purple)1807 wire that comes from/to the VCM is the
wire that I think you should be concentrating on. It comes from C4 connection(Black/Neutral Color)
on the VCM(Vehicle Control Module). You might try to reconnect/inspect (C4).
The purple 1807 from your Data link goes into this connection. I have attached
some more diagrams to help seeing what I am seeing. I am not a guru at this stuff.
I am guessing that if you are not getting any power to position 9 on your Data Link
that somewhere back from there is a break in the circuit. The PPL(Purple)1807
looks to be a very thin wire. I am hoping someone else with some extra knowledge
might pitch in. Electrical problems are tough. You also mentioned above that your MIL light stays on.
It is noted in one of the diagrams that a break in VCM-Pin 5 -Circuit 419 could cause this. I don't think Your MIL light
would stay on because of any Transmission problems. Not positive though.
Mark
With the engine on, at the data link Position 9 should have a small
amount of power. Not sure how much. Probably very little since
it is coming from a computer and going into a OB2 computer
to read info. The PPL(Purple)1807 wire that comes from/to the VCM is the
wire that I think you should be concentrating on. It comes from C4 connection(Black/Neutral Color)
on the VCM(Vehicle Control Module). You might try to reconnect/inspect (C4).
The purple 1807 from your Data link goes into this connection. I have attached
some more diagrams to help seeing what I am seeing. I am not a guru at this stuff.
I am guessing that if you are not getting any power to position 9 on your Data Link
that somewhere back from there is a break in the circuit. The PPL(Purple)1807
looks to be a very thin wire. I am hoping someone else with some extra knowledge
might pitch in. Electrical problems are tough. You also mentioned above that your MIL light stays on.
It is noted in one of the diagrams that a break in VCM-Pin 5 -Circuit 419 could cause this. I don't think Your MIL light
would stay on because of any Transmission problems. Not positive though.
Mark
Last edited by marksoftball; 10-09-2011 at 08:57 AM.
#5
10-09-2011 | 10:25 AM
Senior Member
Joined: Jul 2011
Posts: 658
From: Reading, PA
MIL will activate for trans problems....do you have 1st and 2nd gear? Or does it pull out in 2nd and stay there? If that's the case then the trans is in LIMP mode. Limp mode activates with both hydraulic and computer problems. If the PCM isn't recieving a signal from the trans because of a broken wire or short or vise versa it is possible that it's in limp mode because of this. You might get lucky and fix all your problems when you find the gremlin.
#6
10-09-2011 | 10:56 PM
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i think the transmission is shot as 1rst and 2nd work but slip a little same with reverse. when it tries to go in to third it just revs wildly, also to fluid is burnt and you can smell it when you drive. I just bought a junkyard replacement for $60 so i will see if that works. tomorrow when its light out il check those pins for power. it has an aftermarket keylesss entry so i have a feeling that may be the source of my problem. il keep you guys updated with what i find
#7
10-10-2011 | 04:28 PM
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Beginning Member
Joined: Oct 2011
Posts: 23
im getting 4.5 volts on 9 and a tiny fluctuating voltage at 2, 0.2-0.6 volts. im thinking it may be a bad ground as im seeing 300ish ohms at pin 5
Last edited by bob_351c; 10-10-2011 at 04:31 PM.
#8
10-16-2011 | 02:49 PM
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Beginning Member
Joined: Oct 2011
Posts: 23
sorry to triple post but i really need any advise! does these readings sound right? What could cause it to not comunicate?
#9
10-17-2011 | 02:59 PM
Starting Member
Joined: Dec 2008
Posts: 176
From: Wheeling, IL
Hello Bob,
Not really sure what the readings should be. Did you try disconnecting C4 and checking that connection from the VCM. Everything originates from that point. Hopefully someone else with a little more electrical experience can pitch in. Could be a break in the wires or like you mentioned a bad ground.
Mark K
Not really sure what the readings should be. Did you try disconnecting C4 and checking that connection from the VCM. Everything originates from that point. Hopefully someone else with a little more electrical experience can pitch in. Could be a break in the wires or like you mentioned a bad ground.
Mark K
#10
10-22-2011 | 02:25 AM
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Beginning Member
Joined: Oct 2011
Posts: 23
well. i figured out the problem. it was my code reader, it works on every other vehicle ive tried. i ended up clearing all the codes while trying to get mine to work so i dont know what the light was on for. i got the new tranny in and had it running with the wheels off the ground, only code i got was abs... abs light wasnt on before i did the transmission tho. also i discovered i need to replace the transfercase input seal. didnt discover this until i had everything all bolted back together