CEL diagnostic "handshake" for BG?

[OutbackMat]

My wife's BG threw a CEL last night and I was wondering if there's a self-diagnostic procedure built into the PCM. In my Neon, I can cycle the key on-off-on-off-on and it'll give me a morse code kind of sequence of short and long flashes which correspond to OBD-II codes. I've heard that BHs have this sort of thing, what about my BG?

[Reason]

I never heard of it, I just got a CEL this morning. I'll have autozone read it for free. You should see if anyone will read it for you.

[Huffer]

There are actually green diagnostic plugs under the dash. When you connect these they make the CEL flash and will give you a morse code type readout.

But the more accurate way is to get the code pulled.

[OutbackMat]

Are these plugs under the driver's side? I've never noticed them before. But hook them together and the CEL starts flashing? Exactly what I'm looking for.

I'd love to take the car to Autozone, but the closest one is 15 miles from our house AND wife's work. I'll see if there's another chain that does free diagnostics. I thought Advanced Auto did, but their website doesn't mention it.

[d1giPhux]

Advanced does it as well..

[OutbackMat]

The wife stopped at Advanced Auto last night; the code is P0420: Cat converter efficiency below threshold. Time for the those O2 sensors.