P0040 Bank1 Sensor 1 + Bank 2 Sensor 1 Error

[piyush128k]

Hi Everyone,

Since Covid-19, have been working from home meaning X5 50i F15 Msport package is driven less. Out of warranty from 2019 June. Last extended service was in 2021 June. Anyhow recently since 4/10/23 was getting DTC Error: No Powertrain DTCs or Freeze frame Data is presently stored in this Vehicle's compute. Internet and BMW Service center said to drive the SAV for 100 to 200 miles and error will go away. Error came back upon deletion. So drove it and it went away. Rest of April was good. 5/23/23, same DTC error but all my sensors on the coder were red and this time there was engine light unlike before. I went in to BMW Service center and they diagnosed, spark plugs in poor condition with engine oil on them, Crankcase Vent line leaking engine oil into B1 cylinder and O2 sensor B2 Pre catalyst faulty not reading properly. I got the first two replaced and no engine light but came back after 2 to 3 miles. Anyway I went for a 2000 mile trip thinking error might go away but no it did not. Got busy and engine light would go away and come back multiple times. Finally on 6/12/23, i went in to BMW service center got the O2 sensor replaced so i have paid some good money to fix all that only to see after 2 to 3 miles the engine light came back. Anyway both times i left the service center and getting the engine light back, my SAV was performing damn good. I went in to service center 7/25/23, a 3rd time and they said there was a O2 sensor problem from the top of engine and he swapped it and i left only to find the engine light came back after 3 miles. Just that since 8/15/23 the engine side would rumble a bit. I change all the air filters and cleaned the maf sensors. Rumbling stopped. But from 9/1/23 the rear / exhaust side would vibrate but only when idle. More ide worse the vibration from exhaust side. Also when slowing down and increasing speed would be a jerk at lower speeds. Code says P0040 error: O2 Sensor Signals Swapped Bank 1 Sensor 1/Bank 2 Sensor 1. Knowing less, i used seafoam in gas tank and engine oil tank with guidelines. My pops and burbles came back and on idle it reduced vibration to a great extend. Deleted the error but comes back. I have opened up the damn top part of the engine that i can see the two oxygen sensors. Looks easy to replace just that i don't have the tools. Am i looking at the right O2 sensors to replace? What is the tool name? Please help guide

Thanks in advance for help.
Piyush

[piyush128k]

Originally Posted by piyush128k

Hi Everyone,

Since Covid-19, have been working from home meaning X5 50i F15 Msport package is driven less. Out of warranty from 2019 June. Last extended service was in 2021 June. Anyhow recently since 4/10/23 was getting DTC Error: No Powertrain DTCs or Freeze frame Data is presently stored in this Vehicle's compute. Internet and BMW Service center said to drive the SAV for 100 to 200 miles and error will go away. Error came back upon deletion. So drove it and it went away. Rest of April was good. 5/23/23, same DTC error but all my sensors on the coder were red and this time there was engine light unlike before. I went in to BMW Service center and they diagnosed, spark plugs in poor condition with engine oil on them, Crankcase Vent line leaking engine oil into B1 cylinder and O2 sensor B2 Pre catalyst faulty not reading properly. I got the first two replaced and no engine light but came back after 2 to 3 miles. Anyway I went for a 2000 mile trip thinking error might go away but no it did not. Got busy and engine light would go away and come back multiple times. Finally on 6/12/23, i went in to BMW service center got the O2 sensor replaced so i have paid some good money to fix all that only to see after 2 to 3 miles the engine light came back. Anyway both times i left the service center and getting the engine light back, my SAV was performing damn good. I went in to service center 7/25/23, a 3rd time and they said there was a O2 sensor problem from the top of engine and he swapped it and i left only to find the engine light came back after 3 miles. Just that since 8/15/23 the engine side would rumble a bit. I change all the air filters and cleaned the maf sensors. Rumbling stopped. But from 9/1/23 the rear / exhaust side would vibrate but only when idle. More ide worse the vibration from exhaust side. Also when slowing down and increasing speed would be a jerk at lower speeds. Code says P0040 error: O2 Sensor Signals Swapped Bank 1 Sensor 1/Bank 2 Sensor 1. Knowing less, i used seafoam in gas tank and engine oil tank with guidelines. My pops and burbles came back and on idle it reduced vibration to a great extend. Deleted the error but comes back. I have opened up the damn top part of the engine that i can see the two oxygen sensors. Looks easy to replace just that i don't have the tools. Am i looking at the right O2 sensors to replace? What is the tool name? Please help guide

Thanks in advance for help.
Piyush

no response on how to fix this error and step by step method. i am now getting drive terrain error but goes away. engine light still there. exhaust smoke smells pathetic also

[RED_Y_]

I thought you need your speed limiter removed and you are working on the tune, but it looks like your BMW got CEL and multiple issues. With this kind of approach you won't be able to do much.

[piyush128k]

So one thing important is information gathering. Having a clear picture of what my aims are. Removing any doubt or confusion i have. I might not be able to achieve what i want but question and clarification is good ot be clear on that.
As for the issue(s) on my X5, i dont think it is that bad but i can still fix it. I just wanted to make sure of some steps in fixing it or even any video or pictures. so i fix it and observer cause i have really been nice wiht it.

[piyush128k]

Okay...it been long since i updated cause i had been busy thinking and working on this. tailoring my approach to fix this and I have :-). All by myself. I will explain to the point.

I saw a lot of videos on BMW BOSCH O2 sensor replacement or cleaning and unfortunately most have been for v6 or sedan v8 N series engine but none have the upstream O2 sensors the way mine does and it was hell trying to remove and put them back.

Things with time became bad with respect to the vibrations and rotten egg with burn carbon. Vibrations were only when parked with engine running. Though soon i learnt about seafoam and poured 22 ounce in full gas tank. You can do it on half tank as preferred. Poured 6 ounce in my oil crankshaft depending on the no. of quarts of oil that is used. You can read the instructions.

So my SAV when on and parked stopped vibrating. Anyway i did this one more time. This helps to get rid of carbon getting collected and basically smoothens the ride and great thrust or pickup. Meanwhile i was not driving SAV and was going back and forth in removing the upper covers of the engine until i could see the O2 upstream sensors 1 for both banks. Could also see the spark plug coils.

Well i realized the portion i only need to remove for the O2 sensors. The worst thing was how the O2 sensors were place in the top middle part of the engine bay area. The sensors are opposite to each other like the sides of an angled acute triangle. Yeah try to imagine that. They are very close to each other like just 1 or 1.5 inch away so have to be careful as when trying to remove one sensor the other comes in the way.
There is very less space to move your wrench. Very less space to even get your head there to see the sensors. The bonnet does not let you to see the sensors. Might not be the same for others but it unusual for me.
I bought my tools from AutoZone and Lowes. I use a 7/8 long socket with a gap in between where sensor wire fits. I had a long 3/8 in. Drive Quick-Release Ratchet a for torque, a TEKTON 3/8 Inch Drive x 11 mm Universal Joint Socket and Standard Drive Extension, 3/8 in Female to Male Square Drive, 10 in OAL. I could have also bought a 3/8 drive by 7/8 inch 22mm socket bit i skipped it.

I had already spent around $100 or slightly more for the tools. Bought a $4 plus on carbon cleaner spray for engine and $4 plus on berryman B12 chemtool liquid. So maybe close to $120 and 4 weeks of my time thinking/researching/working on it. BMW was charging to $900 to undo what they did. Infact i think they would have probably replaced them with new one since that price was quoated. The BOSCH O2 upstream sensors for my model costs about $100 each so you are looking at $200. So my sensors were not bad but because they swapped it, an error popped up telling me to swap it back.

So i with great difficulty removed Bank 1 Sensor 1 O2 upstream sensor and Bank 2 Sensor 1 O2 upstream sensor and cleaned them. I did not replace though i should have as they are replaced every 40k to 50k miles. But i want to test what happens if i cleaned and swap them. Most reviews said to buy oem and very few who said you can clean them but engine light might come back after sometime if not working. Now that i know how to remove and put back O2 sensors, if engine lights comes back then to replace them will be less tought.

How i cleaned? I sprayed carbon cleaner and used a brush to remove clean the sensor. Sprayed into each hole at the end of the sensor but still that rotten egg smell existed and tinny carbon particles fell. Then i completely dipped the sensor part in the b12 chemtool chemical to remove any stuck carbon and things that might be stuck in the holes. kept it like this for 5 hours then again sprayed the carbon remover spray. The carbon still came off but smell went away.

I put back the O2 sensors and rest of the engine covers. Finger crossed and started the engine and the engine light was there. I connected my obd device and deleted engine light error but one must stop the engine for completion but just as i was about to do that, my idle was cut short and my SAV was chocking/coughing as if it were not getting power, air and O2. It shutoff. I started the engine and it did the same thing. Shutoff. I started the engine 3rd time and the O2 sensor error did not come back but all my other sensors became red from green. No Engine light there though sensors are red and engine shutoff 3rd time by itself.

Waited 30 odd min, i started the engine, no engine light. Good idle time. A Little louder exhaust. Used obd connecter and my sensors were red with no powertrain dtcs or freeze frame data is presently stored in the SAV computer message (not error). This basically means drive your SAV for like 100 to 200 miles and it resets or fixes the sensor problem. Your SAV needs to be driven more often that its being driven. Drove for 200 miles and all errors and notification gone. Performance is better. I will share pics and videos later as i am super tired from doing this and solving it

[piyush128k]

I took this images till i was able to put back the sensors but with much ease this time. The P error went away and engine light was deleted by me and did not come back. Next day got no power train DTC / Freeze frame data os stored in computer with multiple sensor alerts. Engine light is back. So i just have to drove it and now only fue and emissions sensors are red. I guess when i drive 55mph for 100 to 200 miles it should be okay and engine light should go away or i reset the negative connector of the battery tomorrow.