210 ohms O2 Heater '92 FJ80 throwing code21. Is this a recogized failure mode? (1 Viewer)

[paulzak]

Started getting code 21. CEL comes on when cold, but goes out at freeway speed. I measured the primary O2 sensor heater resistance (@ the separated connector) and get 210 ohms. FSM says it should be in the 4 to 6 ohm range. Is this how these suckers fail? I'd have expected an open before an increase in resistance.

New Denso on the way.

Thanks!