Quick lesson here:
First you need to disconnect both ends by referring to the service manual. Then let's say the below cable is one of your O2 sensor cables (IT IS NOT) with one end connecting to an O2 sensor and the end to the PCM.
1) You would take your multimeter and set it to OHMS on the smallest scale. Then put one meter lead on pin 5 of 1 connector and pin 5 on the other. It should read very little resistance, like under 5 ohms.
2) Then leave one meter lead on pin 5 and touch the other to chassis ground. It should read OPEN or OL, whatever your meter does. That would mean that wire is not shorted to ground.
3) Keeping one meter lead on pin 5, touch the other to pin 2. It should read open just like the test to ground did. Now check pin 5 to pin 3 and look for an open there as well.
We just verified that the wire between pin 5 and pin 5 did not have high resistance, was not shorted to ground and was not shorted to another wire.
Simple right?
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