04 Astra TS CDX: traction control light on, then power loss. No codes

This is the Australian model (Holden). Automatic transmission.

About a month ago I was driving normally and the service light and traction control light came on at the same time. Performance didn’t seem to have been affected. Turned the engine off then on, traction control light stayed but the service light went off. I scanned for codes when I got home with an OBD 2 reader, and nothing was stored/pending.

Next day it was driving fine and neither light was on.

Today the same thing happened, except after the two lights came on, it seemed like the traction control had actually turned off, because on inclines and on my slightly uphill gravel driveway, the car would rev but almost no power went to the front wheels. It seemed OK on flat roads, and I’m not sure it went into limp mode, at least not immediately. Again, no codes have been stored. Haven’t tried driving it again yet.

What could be causing this issue? Also, aren’t all cars meant to store codes when lights come on? I’m using an OBD 2 scanner from a local store that cost about $100. It’s a dedicated device, not one of those ones that sends data to a phone.

I did some research on this, and apparently a misfire can cause this sort of issue because the car will go into limp mode and turn off traction control. There is a definite lag when you floor the car followed by an eventual jolt forward when it’s working “normally”. However, I don’t think it’s misfiring – the idle sounds fine, and it definitely didn’t go into limp mode the first time the light came on.