Well the heaters are sent power with the brown and pink wires and grounded thru the ECM thru the black and red wires.
When I had problems with an O2 heater on one O2 is cut all 4 of the black and red wires out of the connector at the ECM and grounded them to a stud on the kick panel to eliminate it as problem.
It didn't fix my problem but has caused me no problems.
I understand that the ECM failing to ground these is a somewhat common problem.

 

The heaters are working too, though. They're reading correct voltages within 30 seconds or so, before the RPMs drop on cold start.

 

When I had a bad brown and pink connection to to one of my O2's the O2 still had voltage readings put it would not go into closed loop with a heater circuit failure.

 

I started another thread about something similar.

The ECU is not able to detect B2S2 voltages even though I have checked everything connectors, ECU, and all. I even put a 1.5V battery power through the signal wires to the ECU input. The ECU does not detect it at all. Heater wise, the O2 power signal pulses until the loop closes/opens and then becomes a solid 13V. The other bank works fine. Cross checking the b2s2 connector with the b1s2 sensor and it still don't work.

Measuring with a voltmeter directly of of the O2 sensor on the ECU side of the connector, I can watch the voltage cycle like you would expect.

The ECU is not grounding on that one circuit. Not sure if it can be fixed?

BTW this issue raised its head about a month ago, after I had the vehicle for a couple of months and I was screwing around with the diff lock/transfer case connectors. After checking I do not believe it was related.

I am at a loss. I am somewhat reluctant to start messing with the ECU grounding. Maybe I have no choice.

 

Ok, another update. I unhooked the battery and left the leads shorted together while I walked in walmart today. Finally got the codes successfully cleared. I drove 80 miles today and the front O2 codes never came back, so that issue *seems* to be taken care of. That said, Torque still says it's staying in Open Loop, but I'm not convinced it knows what it's talking about. Maybe it does, but I don't have anything else to go on right now for that.

In other related news, she's still missing and it gets worse the longer you drive. I heard some clicking today at idle which appeared to coincide with the misses. It honestly sounded like an electrical snapping noise coming from behind the intake manifold, so that'll be coming off to confirm all the spark plug wires are seated well and I will test them for continuity in case one is broken inside the insulator.

I also have them all sorta bundled together right now, so I'm going to make some separators out of zip ties and see if that helps as well.

I know for a fact I need to get another grill back in my MAF sensor, because changing my intake setup to be a little more of a straight shot definitely helped the miss, so I think the flow through the MAF isn't equalized enough without the grill (it's intended purpose). Still didn't cure the issue.

 

Welp, ochams razor strikes again. The simplest solution is usually the correct one.

I reached back behind the intake manifold and pushed in on all the plug wire ends. Sure enough one clicked just a hair; it was loose. Took her for a drive, maybe 20 miles, and she never missed once. Go figure.

Anywho, guess that solves that problem. I haven't checked to see if that has solved the open loop issue, if it even is an actual issue, but we'll see where that goes.

 

Alex_M, I've re-read this a couple of times and maybe I'm missing it but I'm not clear on what the fix was for your o2 sensor problem. Was it just the new walker sensors?

I'm chasing a problem with my bank2 sensor 1 that keeps dying. I put a new denso in it and it lasted for about 4 days. I *think* my connectors are fouling with water/oil and may just end up with a rewiring job. For me, the newly dead sensor starts off at .9 volts then just steps down to 0 pretty quickly and stays there.

 

Yep. Turned out both the Bosch sensors were bad out of the box. Not terribly surprising considering how many people have been getting bad sensors.

I installed the Walker sensors, reset the adaptive values, and viola; works like a charm.

 

Following this thread. I have the same problem that initiated this thread all 4 sensors not readind.