DelSolDon

'97 Honda Civic EX
D16Y8 w/ auto trans
stock P2P ecu

I have searched thru the posts here and most people that get this code (41) ends up having a bad O2 sensor. However, according to Helms troubleshooting flowchart (see attached images), my O2 sensor is fine as it reads 17.5 ohms between the 2 wires for the heater.

UPDATE: i was going to post a question, but then remembered that i had a spare ECU. Even though this is my first time encountering a bad stock ECU, i guess it does happen. I swapped the ECU out and the CEL has yet to come back. So this post is more informative for people that search this topic rather than a question.

philafelman

if you wanted to check the heater circuit in your sensor, just unplug it and do a continuity check. i dont know which two wires it is though, but you should have probably around 10-14 ohms if the sensor is ok.

DelSolDon

yes, it is between the 2 black wires of the sensor. and actually it can range anywhere from 10-40 ohms according to helms.

philafelman

yeah, from previous experiences, it will read infinite ohms if the sensor heater circuit is bad in the 02 sensor.