Do you know if the primary and secondary o2 sensors are the same/ interchangeable



*** called autozone and lady i spoke with said they are different. Not sure how much she knows though.

 

I think she is probably right.

 

When i did the multimeter test, i tested the secondary sesnor: i put the red in terminal 3, black in terminal 4- got a reading of nothing. switched black to 4, red to 3, and got 2.2 as a reading. When i did the same for the primary oxygen sensor, i got 18.3ohms on with red in 3/black in 4, then i got like 2.1 for black in 4, 3 in red. I think i did the test right, but i'm not confident that the sensor is the reason bad. I wanted to take the sensor off and do the blowtorch test, but the plastic prong connector is attached to metal. Do you know how to get this off, i'm going to have to take it off if i replace the o2 sensor.



-also, if i'm not getting the right ohm's for the connector, which is disconnected from the o2 sensor, wouldn't that mean there is no "power" going to the 02 sensor-therefore there's a short in a wire somewhere?

thanks for the help again.

 

When you uncouple the primary or secondary O2 sensor connector, the male half of the connector remains attached to the sensor, whereas the female half of the connector remains attached to the wire harness.

The first test (Ohm test) in the diagram is done for terminals 3 and 4 of the male connector attached to the sensor. Is this what you did?

Did you also do the second test that measures continuity to ground for terminals 3 and 4? If so, what were the results?

 

When i disconnected, one half is hooked to the actual o2 sensor which is screwed into the catalytic converter, the other half is not connected to the sensor, it separated from it and had 4 holes which is what i tested. I did not test the half of the harness that's directly connected to the o2 sensor. It doesn't look like there is a spot where you can stick the ends of the multimeter for that half, but the half i did test, which is separated from the o2 sensor, had the 4 holes which looked like where u were supposed to test. Did i test the right end?

It just doesn't make sense b/c the end i'm testing isn't connected to o2 sensor.


when i set the multimeter to the volts the screen was reading numbers b4 i even connected the sticks to anything so idk how to read that

 

Unfortunately, you made Ohm measurements on the wrong connector. The first two tests are done on the connector that remains attached to the O2 sensor. You may need to wrap some copper wire around each multimeter probe and use the tip of the wires to probe the less accessible terminals of the male connector. Do the first two tests in the diagram and post both sets of results.

 

ok, i will. How do you read the ground test for continuity? b4 i even touch anything with the probes, the screen is going up and down with numbers.

 

Post a picture of your multimeter with it set the way that your are making Ohm measurements.

To measure continuity, use a piece of steel wool to remove the rust from a small area of the exhaust pipe. With the multimeter set to measure Ohms or continuity, touch one probe to either terminal 3 or 4 and the other probe to the cleaned metal-exposed area of the exhaust pipe. If you detect continuity (=very low or no Ohms), then the sensor is bad.

 

I'm having the EXACT same problem. I replaced the O2 sensor and my ECU is still throwing the code after resetting for 10 seconds etc etc. The multimeter shows no resistance and no voltage from the sensor wires. So now the problem becomes finding the bad part of the circuit, which is buried deep in a long web of other wires, insulation and tubing. What a nightmare... I'll let you know what I find out about fixing this.

 

Was the key turned to ON(II) when you did the electrical tests?