IF you don' have access to a FSM, Morris 4X4 has a view online. Search for Data link connector. the Connector Pin out is on page 8W-80-24

Start with checking for ground and B+ on those pins to rule out the easy stuff.

 

Couldn't find any sort of wiring diagrams. Is it fused somewhere? Everything works in the Jeep and I haven't touched any of the wiring on the inside of the Jeep. I followed the wires to a big bundle of them splitting off into two directions going for the headlight switch and the top plug on the drivers kick panel. Any new ideas would be greatful. No power to any of the pins

 

Then you are not looking very hard the 8w section has all the wiring diagrams


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Okay so my obd2 port is odd. It is now getting power with the key in the off position. When the key is in the on position but not running it's dead. But when my Jeep is running and key is in the on position the obd2 port has power. Has anyone ever had this problem?

 

On the TJ the key position most counterclockwise is accessory which confuses some people as they think most counterclockwise should be off

Not sure on YJ but issues probably related to key switch as it has the electrical connections for on acc and start


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Plus no YJs are OBD2 as came along in 96 and last YJ was 95 then no 96 wranglers made then stating in 97 it was the TJ


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I understand that much but what would make the obd2 plug dead while it's in the far most clockwise position when it's not running but make it have power when the Jeep is running

 

You may be checking the wrong pin at the connector. You would be getting data when running but not when not running. You should be getting constant 12v power from fuse 17 in the PDC which also powers the dome/courtesy lights, the under hood light & the radio. That should be pin 16, a pink/white wire, at the OCDII port.

 

Nope I've been checking the 4th pin and the 16th pin. My code reader gets a signal while it's off in the off position, and while it's running. It gets nothing while it's off and in the on position. Everything works, dome light courtesy light and the hood light

 

Without hooking up your reader, have you checked for power to pin 16 with a test light?

If everything else on the circuit (fuse 17) has power when key on, not running, but not to pin 16 you must have a wiring/connector problem.(?)

Also, when the reader is getting a signal, what code is it showing causing the CEL?

 

I have only checked for power to pin 16 with a voltmeter going from pin 4 to pin 16 not a test light.

Yes everything has power radio, hood light, and dome light. Does the 16 pin wire just run right into that plug on the drivers kick panel? Or does it go further then that and go else where? I've never pulled my dash apart so.

The code had been cleared when I replaced my battery

 

The only trouble with a volt meter is it will show voltage but it could be very low amperage voltage. A test light will better show that by whether the light is bright or dim. Also be sure ground at pin 4 is good. Pins 4 & 5 go through a few connectors & splice together before finally grounding to the engine block.

However, completely losing it the way you are is very odd.

Here is a shot of the circuit. C-108 & C-203 are in the kick panel. Splice 204 is in the main harness crossing under the dash, looks like toward the center. You can see how if the other things are working the data link should too.

Edit to correct C-108 info

 

Thinking about this a bit more, why don’t you tap into a known good power source & connect it to pin 16 to be sure that is really the problem. There is a relay for the cig lighter near the steering column that should work. There is a red/pink wire going to the relay that has constant B+ power from fuse 5 in the PDC.

 

Test light tells me it has power all the way around in all key positions but my code reader is unable to connect and read the code which just popped up. I am however able to read it while the engine is running but not with the engine off but in the on position. Anyone know what that could be?

 

I don’t know how to test this but it seems that the problem must be in one of the other wires, pins 3, 6, 7, or 11. They have to do with data transmission. 3 & 11 are the “twisted pair” so you might research that further.

 

Could it be it has power but the bus connection to the PCM is not active either because of wire connections or PCM not actively communicating


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I thought that besides the twisted pair CCD bus wires or on 2001 the single wire PCI bus there was a different bus wires for OBD

I know for example on OBD2 XJ with auto which are all CCD bus there is another bus wire with a different name the TCM uses to send codes readable at the OBD port

That is why the AW4 TCM has three bus wire pins


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