2001 v70xc
230,000 miles

Tried to get off a patch of lumpy ice today and the car revved but went nowhere. Couldn't tell what wheel was spinning. Managed to nurse the car off the icy patch and into the driveway but it went to limp mode.

I let the car sit for a bit and seemed normal when I restarted it, but went back into limp after about 4 blocks. codes 1618 and 733.

1618 could be the PNP/Gear position sensor. 733 is a missing 3rd gear (I think). Haven't had any trouble w trans and fluid is more red than brown. Is it likely that this is just the gear pos sensor? Seems logical that if the computer doesn't recognize what gear its in, it will throw a transmission code.

Any idea why spinning wheels on ice would bring this on? Clearly the awd did not engage. Is that a cause or a symptom of all this?

Hope this all makes some sense. Appreciate any insights.

Thanks!