The Code that wont die!, CEL 41 in H22 CX hatch
 

I have been at it for months now, and i cant get this damm code 41 to go away. I mean its a 4 wire O2 sensor, how hard could it be to get 4 wires to work correctly. Its a JDM H22 motor in a 92 cx hatchback, using an OBD1 P13 ECU


I have tried 2 different o2 sensors, both of which are factory honda and numerous ways of wiring. I have also tested the resistance across the heating element with a multimeter and at room temp the both read about 13.4 ohms which is in spec of 10-40 ohms called for in the Helms manual.

The code 41 means there is a problem with the O2 sensor heating element, which means i have the 2 wires that go work the meter done correctly. The remaining 2 wires, the black ones control the built in heating element.

The way i understand it the polarity of the wires dosent matter, it just gets a constant 12V current from ECU pin A25 (or any 12v source switched on by the main relay) and then it grounds to plug A6 and the ECU can control the heater by opening and closing the ground on pin A6.

I have run it thru the harness like the Helms manual shows and actually run new wires directly from the sensor to the ecu. I am out of ideas and getting really frustrated,

does anyone have some insight or ideas because im about ready to toss this o2 sensor in the trash and pull the check engine light out of my gauge cluster. Ill buy a beer for anyone who helps me solve this one. https://honda-tech.com/forums/images/smilies/emwink.gif

any help guys?

Re: (cheezoto)
 

Try another ECU???

Its quite possible that the internal circuitry for the heater section of the ECU is fried.

You know that spec is 10-40 ohms and it checks out on the sensor. Have you tried verifying that it is 13.4 ohms back at the ECU connector? Have you verified that the heater wires are not shorted or open anywhere? If you have checked wiring integrity and you know the O2 is good.....time for another ECU....its the last element of troubleshooting if everything else checks out fine.

borrowed a p28 from a friend, still showing a code 41

I have also tried a new O2 sensor

Im pretty sure the wire integrity is ok since i ran 2 completly new wires directly from the ECU to the O2 sensor.

Im stumped, i really dont even know what else to try

Re: (cheezoto)
 

2 things.
1. OBDII code 41 is the O2
2. OBDI 41 appears to have to do with the solenoid on the transmission, and apparently those with the Sport shift automatic.

Depends on what car you have, year model, and transmission.

Re: (Staged5)
 

I am working on mine too, but it's for my pos accord obd2


https://honda-tech.com/zerothread?id=838996

read it somewhere here in h-t about tapping the voltage from the coolant temp sensor to clear the code(for h22 swap in accord) but i can't find it now https://honda-tech.com/forums/images...s/emthdown.gif

Let me know if you can gett the code away https://honda-tech.com/forums/images...es/emdgust.gif

Re: (iam7head)
 

is your car wired for OBD1 with an OBD1 ECU?

If all OBD1 then code 41 is Primary oxygen sensor heater AS YOU SAID ABOVE

Sounds like the black wires are hooked up wrong, O2 sensor is bad, or the ecu could be bad internally.

Have you tried switching ECU's, re-wiring, putting the O2 sensor in a friends car!

Also, try using a friends ecu and o2 sensor that you know work. maybe the O2 sensor coming from your harness is wired wrong.

Did it ever work without the code or as soon as the swap was done, threw the code?

Re: (AMS MIKE)
 

did this cx start as a 1 wire o2 or a 4 wire they came both ways??