As stated in the title, I have a 2005 Legacy that I cannot get to link up with my OBDII reader. This has been an issue for probably 6 months or more and no check engine light as of now. I am coming up on having to have emissions tests run on my car and I cannot get it to pass if I cannot get the tool to link. I have tried many online suggestions such as checking the cigarette lighter fuse, pulling the battery and letting the computer "reset", and checking all of the fuses inside the cabin and under the hood. Am I missing something here? The OBDII tool does get power so I guess the housing with the computer isn't completely dead.

 

Any suggestions would be greatly appreciated.

This could be caused by one of the wire terminals backing out of the OBD2 connector. I'm not sure how the connector is mounted on that car but usually it's sticking out of a plastic panel under the dash. Pull the panel down so you can get access to the back of the connector and try to push each wire into the connector.

 

Pins 16 and 4 are power and ground (respectively), so if the scanner powers up when you plug it in, power/fuses are not a problem.

Thanks for the quick reply. The scanner actually does power up as soon as it is plugged in. I have checked the housing for pins that may have been pushed in and found none, but I didn't think to remove the housing and check the wires. I looked up a diagram and I believe pin 7 is for data transfer; this pin does in fact have power but I didn't think to check the wire. Could that be the culprit?

Is this a bluetooth reader having issues pairing or a standard reader?

Have you gone to Autozone or any local retailer that offer a free read to compare and see if there is actually something wrong with your scanner?

Edited February 24, 201511 yr by brus brother

It is just a standard OBDII reader. I have tried several other mechanics readers, as well, and none of them will connect either. 

How much power on pin 7? If you mean 12v that's a problem, because it should be only 5v IIRC.

 

It needs two data wires to work. Ill have to look up the specific car to find out what should be where on the DLC. But if it has a wire on pin 7, it should also have a wire on pin 15. These will be the data lines if the ECU is using the ISO 9141 protocol.

I will have to double check today, but for some reason I do think that pin 7 had 12V of power and I don't remember about 15. It is a 2005 Legacy 2.5i no turbo.

This should be the DLC diagram for your car. 

 

Subarus pin locations are flipped, pin 1 on this diagram = pin 16 on standard DLC views, pin 16=pin 1, so keep that in mind when looking at this diagram. 

 

Pin 16 is your 12v supply.

pins 4 and 5 are ground

 

Pin 7 will be the data line to the ECU

pin 11 also goes to the ECU. 

 

I'm using alldata at school and the way they arrange info on here is absolutely horrible. I will try to look at the actual FSM at home later and see if I can figure what signals should be on each of those. 

Thanks for that diagram. I have looked in the housing and that is how it seems to be set up. Is it possible that the wire on the other side of pin 7 could be shorting out? The car used to connect, though sporadically and the reader had to be pressed really hard onto the housing to get it to read, and now it won't read at all which makes me think it is a short of some kind. 

If pressing harder into the housing made it work, one of the terminals could be backing out when the reader is plugged in. Easy to check if to can get the back of the connector visible.

Or the terminal is too loose and is not making contact with the pins in the reader plug. This can sometimes be determined by pushing on the plug perpendicular to the connector.

 

Unfortunately there isn't an easy way to tighten the fit of the terminals. But you can pull one of the other terminals out and cut/swap it with the one that is too loose.

Pin 7 I believe is data for Subaru SSM connection. I'm not sure if a standard scanner also uses this wire. I would think the obd2 reader uses pin 11 for data, but I can't say for sure. The terminals on those could be swapped with the ones from the wires that goes to the check connector.

I finally got to check the voltage and the connections of the wires to the DLC. The purple wire (data) actually was loose and I was not able to remove it from the housing. The wire doesn't have any power, whereas wire 16 is getting 12V. Is the next step going to be removing the wire for pin 11?

Bump