[SOLVED] o2 Sensor "Not Ready" Troubleshooting
 

On my 98 SS I noticed it doesn't get into closed loop. The B1S1 o2 says not ready, but B2S1 says ready. I assumed it was a bad sensor and replaced the sensor. Same issue, the voltage on B1S1 never moves. I tested the circuits on the car and heater wire is getting voltage, ground is good, the only thing I haven't tested is the signal wire. The signal wire I assume is what the PCM is getting a reading from, if it's not reading a voltage at all, maybe the signal wire in my harness is broken somewhere? Just a thought, any help would be appreciated. As you can see from the image. B1S1 never moves, B2S1 is behaving as it should.

Is there possibly something in the tune that could've disabled B1S1?


https://cimg2.ibsrv.net/gimg/ls1tech...f4cef5561a.png

Post a tune file

Doubt it's turned off in the file but here's the file.

Stock harness? Unmodified? Check over your grounds at the back of intake really good. Take a multimeter and check o2 signal at the ecm and o2 pigtail. That should tell u if u have a open circuit. Also could be possibilite pcm drivers goin bad. Do u have access to a spare ecm u could try?

O yea what brand o2 did u buy? Possibly a dud? Try swapping bank2 sensor to bank1 and see if problem follows.

Yea stock harness. Checked the grounds and even put a new ground strap at the front. May try to check signal at the pigtail vs what I'm reading in the scanner which is what the pcm sees. My old pcm is toast, I don't think this PCM is bad but never know.

The same Bosch Vette sensor I have already. I'll try tomorrow swapping them.

If you just downloaded a file it will do this for over 50 miles of driving. I always turn mine off in the DTCs.

I've driven the car for well over 50 miles with the scanner hooked up monitoring it and it never went to Ready. I haven't written a file to it until yesterday when I turned the MIL back on for B1S1 & B2S1 just to see if B1S1 would set a code that would be useful to me.

I drove my 2017 over 500 miles and it would not set. I ordered my Z06 new from out of town with no inspection sticker. Turns out new cars done have to pass but in your case best to just fix it in your file DTCs and be done.

I'm just not sure what I'm trying to fix. I wan't it to get into Closed Loop so that I can start tuning it. Disabling the DTC for B1S1 & B2S1 didn't fix my problem, I only turned them on in hopes it would tell me the issue vs me chasing it (e.g. heater issue, low voltage, etc.). Before or after I enabled the DTC's the o2 sensor would not go to ready.

I'm gonna try to swap the o2 sensor from the passenger side to the drivers side today but I'm almost certain it will make no difference.

Because it won't go into Closed Loop, the fuel trims aren't adjusting at all.

Alrighty so I pulled the sensor on B2S1 and replaced it with the new sensor that did nothing when placed on B1S1 and it behaved exactly as it should with no issues. There's definitely something wrong with the wiring or something for B1S1. I may have to just follow the wiring all the way up to the pcm or something. Would anyone know which PIN on the PCM I should be looking for?

I noticed there is a Signal HI & Signal LO going to the PCM, one's a tan/wht wire, one's a purple/wht wire. Which wire should I check and what's the expected voltage/mV?

Edit: I think I found Hi is the signal and Lo is the ground at the PCM.

I may just swap the sensor on B1S1 anyways and drive it around for awhile and see if anything changes. But even if it weren't ready, I'd expect to see some numbers from it?

I was also doing some searching online and some people were saying that some monitors won't "ready" if the rear o2 is turned off in the tune, which mine is. I've never had a problem with this before but the car has been down for a year and just had the trans rebuilt and now I'm driving it around with access to a scanner I never had before. Without the scanner I would've never known about the issue because it doesn't set an MIL.

I'll try to check the pcm connections tomorrow at the pin but if they check out then I will just be lost on where to go from here.

Turning "off" any instrument in the DTC's section (no error reported) only keeps that sensor from setting a code (mil). It will not keep it from actually functioning. You would still see it switch states on the scanner. You have a wiring harness issue almost certainly. Turning the DTC's to no error reported in the proper manner will make it say ready in the rediness function test.

Forgot to add, you don't want to leave your sensor ones (front) in No Error Reported. Have you tested your check engine light to see if it comes on at all?

Yea I'm aware of that. It was off in my file (the MIL that is) but I turned it back on to see if anything shows up.

However, this morning I looked again at my charts and what I thought was B2S1 was actually "o2 volts", I guess it's a general voltage in HP Tuners for all o2's?

When I use "Oxygen Sensor Volts - B1S1 (or B2S1) (Sensor) SAE - it doesn't seem to show anything for either so maybe I don't have an issue and the B1 sensor just isn't ready for some reason? Could it be waiting on the EVAP to ready or just not getting hot enough?

Trying to understand why one bank would be ready and the other one not.

After re-enabling the codes, it seems both o2's aren't working at all.


https://cimg3.ibsrv.net/gimg/ls1tech...f6afb19924.png

Do you by chance have the O2's plugged into rear O2 connectors? You generally have to run extensions with long tubes.

No I'm running the Corvette o2 sensors which are super long.