1990 Honda Accord Code 41, O-2 Sensor

KELLENDAVID

MEMBER
1990 HONDA ACCORD
4 CYL
2WD
MANUAL
158,000 MILES

My car has the "service engine" light on for 8 months, the code is 41, O2 Sensor. I put in 2 different after market O-2 sensors and then put a Honda O-2 sensor in. It still shows code 41, I had an electrical auto shop tell me that it is likely the computer.
I replaced the ECU today, engine light is still on, code is still 41, O-2 sensor.
Is there a heater circuit or under the hood that I can check and replace? Is the heater circuit the same as the o-2 sensor?

1 Reply

CH112063

MECHANIC
1,320 POSTS

The code will say either the o2 sensor is out of value or the o2 sensor heat circuit is out. 2 diff codes. 4 wires on o2 sensor means heated circuit. If car is constantly running too rich, or too lean all the time, the o2 sensor will be stuck in one voltage between 0-1 volts. It is a small battery that reads oxygen when a certain tempurature is reached. Use your scanner, check car running hot to see if o2 sensor is 0 volts all the time, or 1 volt all the time. If 0 no oxygen, if 1 too much oxygen. Fuel pressure? Rarely does computer read and not respond properly. Rare I think the car is running too lean or rich all the time for another reason. Check for fuel pressure first thing. Your welcome.