Freak

hey all, does anyone know where i can find out what the ohms across the heater circuit should be on my O2 sensors? Or where I can find out? I threw a code for it, and I want to make sure that the O2 is bad not the wiring before I go out and buy a new one.

thanks
Troy

samz28

i had this problem when cold with o2 extensions? did you put headers on? I got p0135's randomly, now that its warm, no problem. I think it was moisture and crappy o2 extensions. Only one bank. I datalogged efilive 6.3.3 the o2 activity and both sensors came to full sweep mode with the same peak and trough once CL mode engaged... without the heating circuit working, the o2 sensor would take minutes not 30-60 seconds to come to full temps.. ever had a o2 sensor on a 1 wire o2 sensor? they drop signal at idling periods and take forever to warm up on cold days.

Freak

I have headers, but no extensions. i havent been able to get to an a-tap cable yet to clear the codes and see if they come back. but it doesnt seem to idle quite right even after driving around. but that could be due to an overactive imagination.

samz28

autozone will clear your codes for free

Freak

they read it but it didnt clear. i dunno if that means it is still there or they just didnt clear it

bomax

iTrader: (3)

Testing an O2 Sensor

Freak

thats good info, but Im trying to find out how to test the heater part of the sensor. thats the code Im getting.

I did notice that one of the wires is grounded to teh threads of the sensor. I havent checked the other one yet should it be like that? I assumed that since there are 4 wires, it grounds through there...

samz28

is this consistent? get the codes cleared. Mine appeared mostly on cold humid mornings. Since spring, this code has never come back again, oddly. Most of the time it was me warming up the car improperly (2-5 minute warmups) when the code popped up. NEVER while driving. Swap the sensors around and if you get a P0134 you obviously have a sensor isssue.

prob want to swap both sensors at once for the sake of it. Can you use your old rear sensors? Swap one of those into the one throwing the code perhaps? that would be low cost.

cueball

you are looking for the (C & D) wires, they are the tow wires that go to the heater circuit.
i am not sure about the ohms but i think it mite be around 6-10 ohms
any more than about 35 ohms and it could be burned up
or nothing (OL.) there is an open
and the sensor needs to be changed
hope that helps

500plus

I would agree with samz28. a sensor whose heating element was not working
would take at least 4 minutes to become fully active. how cold is it where you are? it is common to throw this code expecially in cold weather with headers. the easiest way to test a heater is to take both o2s out of the collectors, then reconnect them at the connector. turn the key forward and hold the tips of both o2s in each hand. they should both start getting hot within 1 minute. i believe the resistance of the heater circuit throught the sensor should be about 8ohms, but i dont swear by that. just take them both out and compare the two. the heater circuit is the two dark brown wires.

Freak

i pulled the other side out and the difference was huge, so I got a new sensor. it seems to idle better, but the light hasnt gone away, I havent even driven it yet and It seems better.

500plus

you can clear the codes by disconnecting the battery for 1 hour

WhiteDeathLS1

iTrader: (1)

I have been struggling with these codes ever since I installed the LT's. What a PITA.

Wnts2Go10O

iTrader: (12)

welcome to the club. although i do think its the o2 or extension, ill jus change the o2's around to figure it out.

OBXMarine

iTrader: (2)

Another link on how to test an O2 Sensor.