No voltage at AF sensor (pre-CAT O2 sensor)

[fkertis]

Okay, car is steadily improving. Now I am trying to get the MIL/CEL light out. The code originally read heater malfunction AF sensor 1. Since the sensor had 'spliced' wires, I opted to buy a new sensor and replace it. Having done that, the MIL is still on despite repeated code erasures. Soooo I turned on the scanner to monitor data and low and behold, #1 sensor shows no voltage. (Number 2 sensor is just fine). Before I go through the tedious process of tracing wires for voltage drop, is there a known ailment for the AF sensor that would prevent it getting voltage? (2001 CVT w/196000 miles). Thanks.

[retepsnikrep]

Did you buy a genuine Honda sensor or some aftermarket type?

[fkertis]

Thanks Peter. It was a Beck-Arnley part: 1564231. I confirmed with the manufacturer that it was for the 01 CVT pre-CAT replacement, since the catalog didn't specify MT or CVT. The post-CAT is a new NGK, working fine at this time. Since the leads are long and the harness conectors are close to each other, I plan to swap connections today to see the effect on my code scanner.

[fkertis]

Okay, I traced the wires and found no breaks. DTC is 1166. I am at the point of questioning the ECM. Does anyone have a diagnostic scanner to attach to their 2001 CVT Insight to determine the AF sensor voltage on start-up? Mine is at "0" all the time. I swapped harness connextions with the post CAT sensor and it also reads "0", whereas it previously read about 3.75 volts. The new AF sensor also reads volatge when connected to the harness for the post CAT sensor, so I tend to believe the sensors are not the problem. Help is appreciated.