After replacing the O2 sensor due to fault codes 1166 and 1167, I still get 1167-Heater circuit error. I check resistance through O2 sensor heat, about 17 Ohms. Plug has 14 volts feeding heater. I read somewhere that computer has to re learn parameters to get CEL to go out, after running several hours/cycles. Is this true?
As @FredWilson pointed out, there is no relearn for a heater circuit code.
On a 2.3
Check for power at the ECM connector C pin 13 (white).
On a 3.0
Check for power at the ECM connector C pin 1 (black/white).
While the o2 heater wire may have power there may be a break in the wire that goes to the ECM. This wire tells the ECM that the heater relay is working.