P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2
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Northstar Engines and System Technical Discussion Discussion, P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2 in Cadillac Engine Technical Discussion; I recently started getting a code P0139 as well as an old code P1441 (history). I suppose the o2 sensor ...
  1. #1
    Bill Harrison's Avatar
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    P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2

    I recently started getting a code P0139 as well as an old code P1441 (history). I suppose the o2 sensor is causing my latest problem which is when idling for more than 2-3 minutes with the engine warmed up it just suddenly dies. How do I determine which or more importantly where is the
    bank 1 sensor 2. If this is the only code should I replace more that just the one o2 sensor I am getting a code for and any brands I should stay away from or just go to the dealer.

    Thanks,
    Bill

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    Ranger's Avatar
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    Re: P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2

    Stick with OEM (AC Delco) O2 sensors.

    Bank 1 Sensor 1 = Right Bank (rear) manifold
    Bank 1 Sensor 2 = Pre-Cat
    Bank 1 Sensor 3 = Aft-Cat
    Bank 2 Sensor 1 = Left bank (front) manifold

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    Re: P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2

    Still stalling here's the recap
    1997 deville northstar 144000 miles
    had both crack position sensors replaced, fuel filter, o2 sensor to correct p0139 code and the iac
    i have been getting a p1441 evap code for a couple of years
    the problem seems to be worse when it is hot but maybe that's just me anyway anytime you come to a stop at idle the rpm's start to drop and then the engine dies, no sputtering it just dies like you killed the switch
    p1159 engine stall code, duh, I knew that. if a load is put on by turning the wheel the iac will speed up the engine but let it just sit and idle and it will die within 2 min's almost every time
    yesterday it died coming up to a red light, at about 5 mph but i wasn't watching the tach
    oh yeah my mechanic checked the fuel pressure and said it was good 38 if I remember correctly

    any ideas
    Thanks,
    Bill

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    Re: P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2

    With the P1441 code present I'd check out the EVAP system. Maybe an EVAP solenoid stuck open causing a vacuum leak.

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    Bill Harrison's Avatar
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    Re: P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2

    ok
    how do I located the evap solenoid

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    ewill3rd is offline Cadillac Technician
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    Re: P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2

    P1441 is a code that indicates "flow during non-purge". To the layman that means that there is a vacuum in the Evap system.
    I suspect your Purge solenoid is sticking open or has chunks of carbon in it.
    the purge solenoid should be located on the rear valve cover area towards the driver from the ignition coil and module assembly.

    Remove the purge solenoid and take the inlet (the end that goes to the tank) and bang it so that anything inside will fall out. Use a paper towel so you can see if anything comes out. If black charcoal looking stuff falls out you need to replace your Evap canister and the solenoid. If nothing comes out just put a new solenoid on it and clear the code.

    What's happening is as you come to a stop, extra fuel vapors are being pulled into the intake and causing such a rich mixture that the engine stalls.
    That is also what is setting your DTC.

    HTH

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    Bill Harrison's Avatar
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    Re: P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2

    Thanks
    there are 2 solenoids, one square (canister purge solenoid) according to my local parts house and a round one gm# 1255576, dealer was already closed.

    I replaced the square one but am still getting the code so I guess I replaced the wrong one.
    I tapped the round solenoid as you suggested and only got out one small piece so I guess maybe the canister is ok

    am I on the right track?
    Bill

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    ewill3rd is offline Cadillac Technician
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    Re: P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2

    Where was this square one located?
    I work on so many it's hard to keep track of where everything is for each year. You might have replaced something else.
    One way to check this solenoid is to do this.
    Start the engine and remove the line that goes back to the fuel tank, not the one that goes to the engine. Put your finger over the end. If you feel engine vacuum then the solenoid is likely bad. You might unplug the connector just to be sure the PCM is not commanding it open, although at idle that shouldn't happen.
    Let me see if I can find an illustration of what you are after.
    This is kind of an odd view but this is the rear bank and those bumpy things up at the top of the image are supposed to be the exhaust manifold.
    This is the guy you are looking for. The end you want to disconnect is towards the rear.
    Attached Images

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    Re: P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2

    Only 2 solenoids anywhere on the top of the engine near where you mentioned the only other is egr and fuel(iac & fuel regulator)
    i am not sure if the attached photo's help you or not
    nothing like your drawing

    the round solenoid goes to the rear down the left side (I assume tank or eitherthe square canister located left of the tank) although I have not traced the line

    the two solenoids are connected and the square goes to the block and to the firewall on the right side

    Thanks,
    Bill
    Attached Images

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    Re: P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2

    The drawing I posted is for a '98, I don't have access to stuff for '97 because that was the last year we used books.
    That system is only slightly different.
    The round one in the second picture is called a "diagnostic switch" if memory serves.
    That is basically a vacuum sensor. When the system is purging it sends a signal to the PCM to verify that when the purge solenoid is commanded open, it's actually open.
    If the purge valve is closed and that switch shows flow it will also set the code.

    If you already replaced the solenoid, go ahead and get the switch.
    Is it still stalling after the solenoid replacment? Which one did you tap out the round one or the square one?
    Either will collect charcoal debris if the canister comes apart inside.

    You are on the right track.

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    Re: P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2

    OK replaced bot solenoids/switches and still getting p1441 plus p0139 is back after having 02 sensor replaced and yes it is still dying

    Bill

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    Re: P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2

    You cleared the codes after you fixed it right? Are they setting as current?
    Tell me about the position of the sensor you replaced.
    hmmmmmmmmm.

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    Re: P0139 - Heated Oxygen Sensor (HO2S) Slow Response Bank 1 Sensor 2

    Quote Originally Posted by Ranger
    Stick with OEM (AC Delco) O2 sensors.

    Bank 1 Sensor 1 = Right Bank (rear) manifold
    Bank 1 Sensor 2 = Pre-Cat
    Bank 1 Sensor 3 = Aft-Cat
    Bank 2 Sensor 1 = Left bank (front) manifold
    ranger is right about sticking with oem 02 sensors.i learned that the hard way.i was setting a 02 sensor code i think its a po151 and po154 anyway both of the codes are for that 1 02 sensor.never do what i did.i bought one of those bosch universal 02 sensors.i put it on and cleared the codes and the check engine light stayed out for about 4 months and all of a sudden when i was going to work one morning the check engine light come back on and the service emissions soon lit up on my dash. it was the same codes for the same 02 sensor that i had replaced.i should have bought the oem type but i was trying to save a little money thats going to cost me more because im going to have to buy another 02 sensor.

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