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97 Dakota unable to use OBD II

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Nov 18, 2010, 6:17 PM

Post #1 of 4 (4077 views)
  post locked   97 Dakota unable to use OBD II  

1997 dodge dakota 2wd, V6 3.9L : unable to use OBD II

Firstly, the ODB II scanner is good - I tested it on another vehicle and it works fine. He used the shop scanner and had no success either. He also tried turning the ignition to start position 3 times to see if that would provide any help. No joy.

Today I had qualified tech investigate the diagnostic scanner fault syndromes. He found no opens or grounds, no missing voltages and no wiring related problems at either the diagnostic port or the connector to the PCM. He then checked inputs to the PCM - all good.

He reckons the only thing remaining to do is replace the PCM.

Is it possible that my PCM will no longer run a diagnostic, but will still function most of it's other tasks, because the truck is working pretty good. There was a check engine light on, but that has since disappeared when he did his troubleshooting today. I expect it to return shortly.

Does anyone have any further recommendations ?


Veteran / Moderator
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Nov 18, 2010, 7:35 PM

Post #2 of 4 (4073 views)
  post locked   Re: 97 Dakota unable to use OBD II  

Well is possible the PCM is bad but you may want to check out a couple of other things

1st would be to make sure the DLC has batt power to it and there isn't a blown fuse. pin 16 should have batt power. If it's a good scanner you are using, see if you can communicate with any other modules, this will tell you if the network is down.

If you can't communicate with any then check the voltage at pins 3 & 11, this is for your CCD Bus and how the computer talks to the scanner. If you are using a volt meter both with be around 2.5v, 3 is high & 11 low so the voltage will be just above 2.5 on #3 and just below 2.5 on #11.

I'm sure your tech has probably already done this but thats all that comes to mind right now, I'm sure if I've forgot something someone else will jump in & help us out......

New User

Jun 11, 2013, 6:32 PM

Post #3 of 4 (2969 views)
  post locked   Re: 97 Dakota unable to use OBD II  

I have a similar situation. My 97 dakota 5.2 engine does not pass smog it looks like running rich. The guy at the smog place said the computer was not on yet when he checked smog. I do not have any check engine lights on and the scanner does not show anything. My emissions are really high. Anyone have any ideas to at least get the ob2 to work.

Hammer Time
Ultimate Carjunky / Moderator
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Jun 11, 2013, 6:49 PM

Post #4 of 4 (2966 views)
  post locked   Re: 97 Dakota unable to use OBD II  

Please read the FORUM RULES before posting. This is a 3 year old thread.


We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.

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