Wiring Resistance Ohm Question

[landtoy80]

I am checking my O2 harness repairs I made over the years. I am using a Ohmmeter.

No. 1 Heated Oxygen Sensor (the shorter of the two harnesses) I got 00.0 Ohms. I replaced the plug end wires about 1.5 years ago.
No.2 Heated Oxygen sensor (the longer wired harness) I got 00.6 Ohms on three of the wires and 00.4 Ohms on one of the wires on the harness. I repaired them about 175,000 miles ago.

Is the 00.6 and 00.4 Ohms be a problem with wires that go to the O2? Will that mess up the reading to the ECU?

 

[blkprj80]

My meter leads themselves are typically 0.3 or 0.4 ohms if I short the probe tips.

How are you measuring this? What meter? I wouldn't think a few tenths of ohms would be an issue. What is the resistance of the heater and sensor when you measure the o2 sensor itself?

I have both old o2 sensors I removed if you need me to get a reference measurement. I was throwing a P0420 code, cat converter efficiency. I haven't seen it in the 1000+ miles since I changed them. So, my sensors may not be a good reference.

 

[landcrshr]

You didn't mention which points you're measuring between, but anything less than 1 ohm is effectively zero.
The resistance of your test leads alone can be almost 1 ohm.

 

[landtoy80]

I have about a 15 year old Radio Shack multimeter. Strange enough it still had the original Radio Shack batteries in it and they still worked. I just put new batteries in to to see if I could check resistance in the EGR temp sensor and it still couldn't get a reading.

I get 00.0 ohms with touching the tips/leads together. I get 00.0 with the roach clips on the ends and a wire on them with a probe on them to insert into the plug connectors.

I am measuring between the plug/connector to the ECU to the connector to the O2. I am testing the harness that I repaired last year and the one that was repaired many years ago. Its the one I repaired many years ago that has the 00.6 and 00.4 ohms reading.
I got 00.0 ohms on all the passenger side O2 harness to ECU. The driver side I got the 00.6 and 00.4 ohms from the ECU to O2 harness connector.

I got 5.0 and 5.6 ohms when testing O2 sensor. Range is 5.0 to 6.5 ohms at 68 deg F. FSM says to shows to measure 2 of the 4 wires of the O2. It says +B and HT. That is what I measured.

On the wiring harness, I unplug the connectors from the ECU. I removed the ECU from behind the glove box. I find the proper wire in the connector via the FSM and insert the lead in the connector and check the connector that goes to the O2 with the other lead. Example: Wire OX1 runs to #1 O2 sensor. At the connector to the O2 one of the four wires contains the wire called OX1. It runs all the way from the ECU to the connector to the O2. I set my multimeter to beep if there is a connection and then I read the ohms. All eight wires beeped and I recorded the ohms.