Oxygen sensor replacement

Hi,

Since this is sensor 2, it should remain somewhat steady around .5 volts.

If that isn't close to what you see, go back to the ECM to see if it is different.

Joe

What was the voltage readings you were getting at the sensor? If it is within in range and you are still getting a code and the ground is good, then there is likely an issue with the ECM. If the voltage wasn't within spec, then we need to check voltage at the ECM.

If the sensor is good, the wiring is good, the voltages are good, and you still get a code, then the problem is likely in the ECM.

If the voltages are not within spec, then we need to check the voltage at the ECM.

Let me know.
Joe

If I can just jump in and offer my observation. If your downstream sensor is not reading a voltage on your scan tool then I suspect Joe is correct that you have an issue with the ECM if the wiring checks out as you stated.

When you are monitoring information on the scan tool then you are basically just viewing what the module is seeing from the sensors. So if you are getting 0 volts on the downstream sensor according to the scan tool then you either have a wiring, sensor, or module issue. You said the sensor and wiring check out. This leaves the module.

So when you checked the wiring, can you give the detail about how you checked it? I assume you check resistance but how did you do it and what were the measurements for each wire? Did you unhook the connectors at the ECM and sensor or did you back probe? This is important because if you prove out the wiring is ok and the sensor is not the issue then you have either a connection issue (rare) with one of the terminals at the sensor or ECM, or a module issue.

The way to check this is to do as Joe stated, what are these same voltages at the ECM using a meter. Just connect everything up and then back probe the ECM connector. If you have proper voltage at the ECM on your meter then you know the ECM is not accurate or that terminal at the ECM is not making contact with the ECM terminal. However, if this is the case, I suspect when you back probe it, you will get intermittent contact or it start registering. So I always leave my scan tool hooked up and monitor what the module is seeing and what you are seeing on the meter.

If the meter says proper voltage at the ECM and the ECM doesn't then the ECM is the issue. However, if it starts working while you have it back probed or you see the voltage jumping around while you are moving the back probe then you have a connection issue at the ECM connector.

Hopefully that helped. Thanks