z-ya

iTrader: (1)

I am having a problem with bank2 ltrims at -06 to -15 when the bank 1 ltrims are right around 0.It will show a p155 code once in a while also.I checked the wiring on sensor 2
for the o2's but found no defect.I changed sparkplugs also
with no help.The plugs that came out looked good,but the car has a shakey idle when in closed loop.I also changed
bank 2 o2 sensor with no help.Cross counts on bank 2 are lazy compared to bank 1 on my in car scan tool.I checked the o2 extentions for ohms and all was well also.Anybody
have any ideas on this problem.Thanks in advance for all your replys.
Mark Johnson

Wildman

P0155 is HO2S Heater Circuit Bank 2 Sensor 1.

You said you tried new O2's.
you can try swaping them from one side to the other,
to see if the problem moves from side to side,
If that doesn't work you know your O2's are ok.

I would highly suspect anything else, cause you would
be throwing other codes if it was spark or fuel.

Hope this helps, good luck.
Paul

z-ya

iTrader: (1)

So you are saying it's the circut for sensor1 bank 2 heater? Can I check this circut with the car not running?The wires for this circut come
directly from the pcm to the extender to the o2 sensor,4 wire sqare connetor.Is that correct?
What values should I see on this circut?
Thank again for the reply.

z-ya

iTrader: (1)

So you are saying it's the circut for sensor1 bank 2 heater? Can I check this circut with the car not runn

Wildman

I don't believe you can check this without the car running. But look this up and it will tell you what is causing the code and you can go from there. The idea above was just a simple and cheap way to eliminate your 02's as the problem.

goto page 61

http://carprogrammer.com/Z28/PCM/LS1/Holden_LS1.pdf

Wildman

Oh and BTW, it is not unusual to have the Ltrims not equal, but I agree that seems too far out of tolerance. And you definately shouldn't be throwing error codes.

Team ZR-1

If the O2 and it's wiring is OK then I would look for a exhaust or vaccum leak on that side or a stuck check valve for AIR.
You could verify the heater is getting voltage with a VTOM from PCM via its 2 wires and also see if the biased .450 mvolts from PCM is getting to the O2 without engine running but key on but if your using a compliant EPA PCM scanner it has to have a O2 test that returns results as to all phases of 1 O2 cycle and then compare that to the other S1 O2.
If air is entering that side causing exhaust to stay cooler even if heater is working the DTC would still set being even with heater on the temps are too low.

JxxxOxxxE

iTrader: (1)

OK, the P0155 & P0135 codes are not unusual to get with longtube headers. I have already gotten one since the weather has started cooling off...

If I remember right, P0135, and P0155 have to do with the O2 sensors not heating up fast enough. Mine do it all the time in the winter. I think the general concensus is that since they are farther from the motor, they take longer to warm. If they are not up to temp within a certain amount of time, then you get the code....

z-ya

iTrader: (1)

Yes but that doesn't explain the shakey idle that has deveolped in closed loop or the unequal ltrims.I failed to mention that I also did the air restrictor mod and installed
new check valves when I did the plugs.The exhaust is also
leak free.Thanks to all for the help.This problem is starting to annoy me.I hope its not a pcm problem.Team z1r i only have a ramchargers scanmaster to work with.

z-ya

iTrader: (1)

Well i got the vom out and the values on the o2 plug look ok.I got my assortment of sensors out
and pluged them in one at a time and checked that the heater was working.I put my freshest one in and went for a ride.Now car runs better but bank 2 ltft is +25 when bank 1 is around 0 wtf.The 02,s read way low on bank 2 and do not fluctuate.Car now codes P1153.Think i'll try a different sensor and see if I can get some crosscount action.

z-ya

iTrader: (1)

Well I went thru my assortment of sensors and also replaced the extention on bank 2,no help.
I do have a rub mark on the header on that side
from a speed bump but I can't here a leak.Any more ideas?

Slowhawk

iTrader: (12)

If you have a SLP fan switch I would unplug it.A while ago some wrongly wired ones were sent out.They screwed up bank 1 plugs causing crappy idle.Just a thought.

If nothing else I would agree with ZR1,exhaust leak before or near sensor.If thats not it I would replace the 02 extension wire.

z-ya

iTrader: (1)

I just changed the extension wire with a new one.
I don't have a slp fan switch,but I do have a 160
thermostat and fans set accordingly.The o2 readings on bank2 never go below 480 and switch
way slower than bank1.When I get on the throttle
hard the readings rise but still don't switch properly.When I go back to cruise the readings drop even when the engine is fully warmed up.This
is starting to drive me nuts.

Colonel

I would replace the front O2 sensor on the passenger's side with a brand new O2 sensor (if it's not that then you'll just have another O2 sensor to add to your collection) and go from there.

Wildman

There is a simple rule of electronics, if you 2 of the same components, and you suspect one is bad, swap them out.
If the problem moves, then you know it was the component. If not, then you have eliminitated it as part of the problem. And best of all, as I suggested before, this is free.
First thing to do is swap the 2 front ones.

z-ya

iTrader: (1)

Thank you for all the suggestions and help,it is greatly appreciated.I did move the two front sensors side to side early in this process.The problem stayed on bank2.This led me to believe it was a wireing issue and I cheked the wireing to the best of my meager ability,wires are not my strong suite.I bought a new extention to rule out that possibility.The o2 sensors I am swaping have between 5 and 17 thousand miles on them I put 2 new ones in when I did the Headers 5 thousand miles ago.I really don;t want to buy another o2 sensor if it is not needed since they are rather spendy.I have been chasing my tail on this for a month now,and am reluctant to drive the car in this condition.Is it possible for this to be a pcm problem?Oh buy
the way the gas mileage went in crapper also.

z-ya

iTrader: (1)

I can't seem to find any exhaut leaks ,no noises any way.Does any one have a way to verify an exhaust leak?This is all I can think it could be at this point.