Went to smog my 98 SW and at two different shops the OBD module was not working. First shop the copmuter screen read "Unable to read..." at second shop, the portable computer didn't power on after plugging into my car.

This is the first time I've ever even heard of a OBD module not sending a signal. Any ideas on where to start to determine the cause? I do not have a manual yet so any direction of where to go from here let me know. This thing just plugs into the car's computer right?

 

There's a fuse for em. I dont know which one for the s cars, but the ions share it with the a/c adapter port

 

is there anything else not working on the dash? Lighter? Radio? I believe it is on a shared fuse.

I have a chilton's 91-93 and a crappy chiltons that covers EVERYTHING with its TYPICAL wiring diagrams. I'll spend some time later and see what fuse it shares.

Could of course be a wiring issue, but let's rule out the simple stuff first

 

Most cars share a fuse with the lighter circuit. When you twist the phone charger in the port it will blow the fuse. I will look for the circuit number.

 

Got tired of squinting at schematics.
Research points to either the 10 A Body fuse, or the lighter fuse.
I'm pretty sure they are both in the instrument panel junction box

You can also test for Voltages at the pins on the connector.

The fact that one scanner powered up and the other didn't (they get their power from the diag port) leads me to believe it is more likely either corrosion at the fuse terminals ---sweep them clean by removing and reinserting several times---or a loose/damaged power or ground wire to/at the connector.

It's also entirely possible that the mechanic's scanner terminals are worn and did not make proper contact with your port. Many instances of people failing inspection for no diag port communication, then taking it to another shop and getting it to read just fine.

 

BODY FUSE in the side panel under the console. Smogged yesterday, BACK ON THE ROAD for the mother inlaw!!! Thanks everyone.

 

No problem bud

 

was pretty sure it was the body fuse---just laying out other possibilities. Glad none of them were true.

Happy trails.

 

You know, I am also having trouble with my diagnostic port... It's not required for smog or anything, so I can drive my car regardless, but the port doesn't always want to make a connection... I can usually wiggle the accessory that plugs in, and make a connection... Is it possible to repair the port or replace it entirely?

 

sure you can repair it

First you need to figure out if the voltages are correct at the pins, if the pins are loose on their wires, or possibly the access you're hooking up has worn sockets for the pins and is not making consistent contact