No OBD port Communication, HELP!!
March 3rd, 2012, 12:42 PM
#1
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No OBD port Communication, HELP!!
I cannot pull codes from my Modis Snapon Scanner. Was able to a few months ago then I ran into some car issues.
On the DLC( data link connector ) under the dash I tested the wires for voltage.
Orange wire pin #16 - Confirmed 11.86V using pin #4 and pin #5 grounds, also using seat rail bolt as a ground.
Purple wire pin #2 - No voltage at all using pins #4 & pin #5 as ground and seat rail bolt as ground.
Tan wire pin # 9 - Confirmed 3.70V using pins #4 & #5 as ground and seat rail bolt as ground.
The purple wire from looking at diagrams looks like it goes straight to the PCM. Should this wire have 5V with key in on position?
On the DLC( data link connector ) under the dash I tested the wires for voltage.
Orange wire pin #16 - Confirmed 11.86V using pin #4 and pin #5 grounds, also using seat rail bolt as a ground.
Purple wire pin #2 - No voltage at all using pins #4 & pin #5 as ground and seat rail bolt as ground.
Tan wire pin # 9 - Confirmed 3.70V using pins #4 & #5 as ground and seat rail bolt as ground.
The purple wire from looking at diagrams looks like it goes straight to the PCM. Should this wire have 5V with key in on position?
March 3rd, 2012, 5:05 PM
#2
If it's the same 1995 Cavalier in your other thread, it needs an OBD-I compliant scan tool with a proper DLC connector or adapter. Either your scan tool doesn't support this vehicle or there's no trouble codes to be read. The CEL on with key on, engine off is normal and doesn't mean a trouble code is set. The CEL means something only if it's on with engine on.
March 4th, 2012, 12:27 PM
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I guess I should have been more clear..."WE" couldn't get it to read. There is absolutely no communication, not for just pulling codes but anything like ABS system, Transmission, Engine, etc.
How do I find out what voltage the Purple wire should be reading?
How do I find out what voltage the Purple wire should be reading?
March 4th, 2012, 1:00 PM
#6
Pin 2 is designated for Class 2 serial data which rests at signal ground. You're going to need something more sophisticated than a voltage measurement to see if anything is going on. That is if it's actually connected and live at all.
March 6th, 2012, 11:14 AM
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Well here are pics of the corroded PCM. I am going to try swapping it out with a new one to see what the results will be. You think maybe I should open it up to see if I see anything out of the ordinary like something shorted out or burnt?
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March 7th, 2012, 9:56 AM
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I am about to drive around with the new one in and still see if it stalls under heavy acceleration..If it does I am going to reseal my old PCM, and then the only thing I can think of to check would be fuel pressure??
May 24th, 2014, 9:47 PM
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no communication on my 1995 cavalier
Just replaced head gasket, now have checking engine light comes on after warm up & at highway speed tried multiple types of readers all can't connect to the PCM. Also car runs rough when check engine light comes on. Please help!!