Hey guys I have an interesting problem to diagnose. Prior to my LT install I bought an Aeroforce Interceptor Scan gauge which plugs into the OBD2 port and monitors a number of parameters from the PCM. I noticed as I was monitoring my 02 switching between Bank 1 and 2 that bank 2 would basically stay about 440-450 mv and bank 1 would switch like normal 10-850 mv. Like I said this was with the stock exhaust and cats. Car ran great like this and I figured I had a 02 sensor going bad even though I had no DTC codes.

So during the LT install I replaced both front sensors with the Bosch 13111's. SAME thing is happening! Bank one switches like normal; bank 2 switches around 440-450 mv !!

I had a local friend from here Billiumss delete my rear 02 and AIR codes Saturday. He uses HPtuners. Now here is the interesting part....when he was hooked up and data logging as we drove around BOTH bank 1 AND 2 sensors were switching exceptionally well at idle, cruise and WOT!! But it showed bank 2 as Not Ready in red on his laptop for some reason even though we could actually see the switching occuring as we drove! The car ran awesome as well. Bill and I are both puzzled.

Any idea what the heck could be going on here? I am questioning the Interceptor gauge itself? Any ideas would be appreciated.

Mark

 

well it takes a bit for the codes to cycle once you do a flash so that might be why it was showing not ready...if its switching fine via hptuners I would definitely trust that more then the aeroforce gauge

 

Because the A/f ratio goes to about 13 at WOT the o2s should not switch there. Are u sure. Next time I drive my car I will watch the o2s on my gage

 

yeah i doubt they were switching at wot, he probably meant that they acted normal at wot meaning they went to 850-950mv at that point rather then hovering at 450mv

 

If it finds a fault with the O2 it may just force the
midrange value out from the PCM on that bank. It
could be a stale code or it could be a slow warmup
and just the heater code, immature pre-SES doing
it.

Be sure that you aren't looking at something like B1S2
rather than B2S1 (driver's rear vs passenger's front).
With the rears gone those O2 signals -should- float.
Easy to pick the wrong mumbo jumbo out of the list,
to look at. Or for the tool to have a typo in it. Might
look at all 4 and just pick the two "live" ones.

 

Correct.....except the Bank 2 always stayed around 450 mv no matter if idle, cruise, or WOT (this is what I observe with the Aeroforce Gauge)

Like I said when we were logging with HPtuners it was showing BOTH 02's switching properly as they should even though on his HP screen it still showed bank 2 as 'Not ready' ? I cant run the Aeroforce gauge and HPtuner at the same time to compare. Somehow the PCM is saying Bank 2 is 'Not ready' BUT the 02 sensor is still switching and working properly. I am starting to wonder if it is a wiring issue within the PCM.

 

IT is just the wiring from your Extentions are Bad, I would pull it off on that side and check with an ohm meter to see if there is a bad connection at that point.

 

does the logging software support Mode6 data ? Not ready means that the heater tempature or more correctly the current ramping output watchdog has not confirmed heater to be operating correctly most likely. could just be a bad ground connection at the O2 sensor plug.

 

Both front O2 were switching great.

I might have saved a log, if I did I'll look at it again. Hopefully I wasn't looking at a rear O2 in the status bit section.

 

I checked the log and I was logging just the front O2s, B1S1, B2S1.

It said in the status bit "Not Ready" for Bank 2

 

It would have to be a problem with the wiring from the PCM to the plug connection because I dont have extentions. I used the Bosch 13111's after the LT install. Whats puzzling is that the condition has been the same before LT's (stock exhaust) and with LT's and new sensors. Therefore I would believe eliminating the sensor itself as the cause.

I will probe the connection this weekend to see what I find.

Thanks guys for the input and keep it coming if you have any other suggestions. I apprecaite it.

Mark