zeroptzero

I changed out my cat. converter and the primary o2 sensor, now I'm getting a CEL on the secondary 02 Sensor in the cat conv. This sucks as I now have to go under the car again if it doesn't go away. The CEL comes on about 10 minutes after driving, I can clear it but it has returned every time , usually about 10 minutes and during steady state highway driving conditions. If the 02 sensor is bad wouldn't it light up the CEL as soon as you start the car ?. Does this mean my 02 sensor is dead ?. I did a search but it sounds like my CEL comes on differently than others. The car runs like absolute mint, perfectly flawless other than the light on the dash, it doesn't drive any differently with the CEL on either. The factory secondary sensor has about 55k miles on it. Thanks for any advice.

CKit

Secondary sensor CEL doesn't affect drivability.

What CEL is it? I've seen people purchase the wrong sensor and put a 2' sensor in the 1' sensor position.

MasterForce

you prolly need some anti foulers..

zeroptzero

it's the factory OEM secondary 02 sensor. It's the original one on my car, I just removed it and installed a new cat. conv. and then reinstalled the O2 sensor back into the new cat. The sensor was working fine with the old cat, but after I put it into the new cat it has been acting up. I'm getting code P0141 CEL, which is the secondary o2 sensor. Thanks for the replies.

Slows2k

The heater element is dead in the sensor. Anti foulers wont fix that. Shop for a new sensor to turn the light off.

zeroptzero

thanks for the reply, looks like I'm going to need a new sensor. Sucks that it decided to croak after I swapped it into the new cat. I wonder why it takes about 30 miles of driving for it to activate the CEL, you would think that it would activate as soon as you start the car. Thanks again for the info , looks like Im going under the car again

Slows2k

Think of the 02 heater element as a light bulb filament. They can make contact and work, then when they heat up the filament opens and they don't work.

iam7head

take it easy with the newer o2 sensor, they are very sensitive, lots of people break them by not handling it properly.

i think the code for heater circuit malfunction is 41, i have the same on my old accord, don't get those universal sensor because it's not going to fix it(bosch pigtail and clip on)

Slows2k

P0141 is the correct OBDII DTC for a secondary 02 sensor heater failure.

P0135 is for the primary.

SpitfireS

Contact / ignition should be OFF.

Just for fun:
Measure the resistance between sensor pin #3 and #4.
It should be between 12-14.3 Ohm @ 20C (68F)
Its a square connector, pin #3 & #4 are both opposite of the retainer clip.
You can check it too on the new one.

For more fun:
Check for NO continuity (= endless resistance) between the sensor itself (the metal) and both pin #3 and pin #4.

To finish it off:
Check for battery 12V on cable pin #3 and #4 with the igntion ON.
They didn't specify what is +
Its fuse 6 / 15A (might be different in US cars).

Oh well..