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On a 91 civic lx sedan, where would I fine plug for diagnostic scanner and is it odb, or odb1, I looked behind glove box, behind dash on drivers side, and around both kick panels,, didnt find it, any help would be highly appreciated,
thanks in advance for any help.

 
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Blink codes are all you get in a car that old.

If the check engine light comes on, you yank the carpet away from the ECM and count the blinks of the LED inside the ECM. Possible blink codes are numbered 1 thru 20, in standard one and two digit sequences.

 
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ok, and where do i find the ecm?

 
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Bolted to the floor under the footrest on the passengers side.

 
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and what if check engine light doesnt come on? will it still have codes?

 
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Consider .....if the light bulb for the CEL burned out.....
What do you think?

 
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No, cel is working, I unpluged something just to see (iacv) light came on

 
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That's how it works.


Now you can go check out the LED on the ECM and count the blinks to see what the code number is.

Don't forget to erase the fault code(s) after you are done playing around.

 
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Negative,, cant find ecm,,pulled up carpet under pass, driver, looked under both seats still cant locate ecm,, 91 civic lx sedan.

 
Rep Power: 518

Let me try this again:


What do you have covering your ECM? A metal plate your feet rest upon. Unbolt the plate from the floor to see this unit as seen in the pic above.

 
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ok, so its under another metal plate? will have to look in am thanx, I know I sound like a dummie ,, but your help is really apprreciated

 
Rep Power: 518

Pull the carpet back and post a pic?

I'm thinking there might be a hole in the footrest plate you can look through to see the LED inside the ECM.

In the pic I posted you can see the diamond shape area on the middle of the ECM, in the center of that is the hole you view the LED through.