P0036 and P0038 BMW 520d

lausp

Hello,

Car is a little lumpy on start in cold weather for maybe 5 seconds but otherwise fine, no warnings on dash.

OBD2 Scanner is showing p0036 and p0038 on my 520d (2015), I had the car in for an interm oil change and the mechanic mentioned it to me also.

Seems to be one each of a pre and post cat sensor.

Would anyone know the correct part numbers for these and the best place to pick them up?

Xcellor

lausp wrote: »

Hello,

Car is a little lumpy on start in cold weather for maybe 5 seconds but otherwise fine, no warnings on dash.

OBD2 Scanner is showing p0036 and p0038 on my 520d (2015), I had the car in for an interm oil change and the mechanic mentioned it to me also.

Seems to be one each of a pre and post cat sensor.

Would anyone know the correct part numbers for these and the best place to pick them up?

Had to replace the post cat sensor on mine. Can't remember where I got it but will have a look at emails.

In my case the revs were twitching and didn't feel so smooth.

Easy to change.

Xcellor

Xcellor wrote: »

Had to replace the post cat sensor on mine. Can't remember where I got it but will have a look at emails.

In my case the revs were twitching and didn't feel so smooth.

Easy to change.

P0141: O2 Sensor Heater Circuit (Bank 1 Sensor 2)

This was the fault I had. It's different from what you have.

Dirty Nails

lausp wrote: »

Hello,

Car is a little lumpy on start in cold weather for maybe 5 seconds but otherwise fine, no warnings on dash.

OBD2 Scanner is showing p0036 and p0038 on my 520d (2015), I had the car in for an interm oil change and the mechanic mentioned it to me also.

Seems to be one each of a pre and post cat sensor.

Would anyone know the correct part numbers for these and the best place to pick them up?

Whatever about it storing faults,I'd seriously doubt that they'd cause 5 seconds of lumpiness on cold start. Those sensors are prob running closed loop until they warm up anyway. Bad glow plug or weeping injector would be a guess.

BavarianCare

Dirty Nails wrote: »

Whatever about it storing faults,I'd seriously doubt that they'd cause 5 seconds of lumpiness on cold start. Those sensors are prob running closed loop until they warm up anyway. Bad glow plug or weeping injector would be a guess.

Sorry, but that highlights total lack of understanding.

Regarding his fault - some had wiring chafing issues at the tranny wire clamp.
But my recommendation would be to get it checked professionally.

lausp

Thanks, I'll be bringing it in anyway. The garage I had it in for the oil change don't have BMW diagnostics but I use another place that does.

He did mention that there may be an injector issue as when the engine is cold and in drive on the brake, there is a slightly louder noise at stationary until the engine warms up.

Dirty Nails

BavarianCare wrote: »

Sorry, but that highlights total lack of understanding.

Regarding his fault - some had wiring chafing issues at the tranny wire clamp.
But my recommendation would be to get it checked professionally.

Maybe lack of understanding,but not as much as you think.
OPs next post mentions possible faulty injector.

https://patents.google.com/patent/US8418439B2/en

In the event of cold start of a motor vehicle, a NOx sensor operates accurately after it warms-up and reaches an activation temperature, sometimes referred to as a light-off temperature, before it can accurately measure the amount of NOx contained in the emissions. During the warm-up period, which can have a duration of up to several hundred seconds, the NOx concentration measurements may be affected by an initial (e.g., ambient) temperature of the sensor causing an erroneous NOx reading. As such, the NOx sensor reading is generally ignored during this time. The above reference, while addressing temperature variation of the sensor during operation, fails to address the ambient temperature detection affect on the sensor during warm-up.

BavarianCare

Dirty Nails wrote: »

Maybe lack of understanding,but not as much as you think.
OPs next post mentions possible faulty injector.

https://patents.google.com/patent/US8418439B2/en

In the event of cold start of a motor vehicle, a NOx sensor operates accurately after it warms-up and reaches an activation temperature, sometimes referred to as a light-off temperature, before it can accurately measure the amount of NOx contained in the emissions. During the warm-up period, which can have a duration of up to several hundred seconds, the NOx concentration measurements may be affected by an initial (e.g., ambient) temperature of the sensor causing an erroneous NOx reading. As such, the NOx sensor reading is generally ignored during this time. The above reference, while addressing temperature variation of the sensor during operation, fails to address the ambient temperature detection affect on the sensor during warm-up.

What you said: "Those sensors are prob running closed loop until they warm up anyway."
Reality: Those sensors CAN'T run closed loop until they heat up. Hence the heater... So it can warm up AND CAN GO INTO CLOSED LOOP.

See what I mean?

Now, the NEXT thing - what is difference between NOx sensor and O2 sensor?
Again, a total lack of understanding...

My original point stands.
There is total misunderstanding of the codes and the correct method of diagnosing them.

The 'leaking injector' does not relate to the codes posted.
And my advice was: 'Get it looked at by a professional.

That advice still stands.

Dirty Nails

BavarianCare wrote: »

What you said: "Those sensors are prob running closed loop until they warm up anyway."
Reality: Those sensors CAN'T run closed loop until they heat up. Hence the heater... So it can warm up AND CAN GO INTO CLOSED LOOP.

See what I mean?

Now, the NEXT thing - what is difference between NOx sensor and O2 sensor?
Again, a total lack of understanding...

My original point stands.
There is total misunderstanding of the codes and the correct method of diagnosing them.

The 'leaking injector' does not relate to the codes posted.
And my advice was: 'Get it looked at by a professional.

That advice still stands.

Post 4 Should have said open loop instead of closed loop. That's all I'm giving you so your Shouting rant is after landing on it's arse.

It's heater circuits faults so nox or o2,the principals are the same.

Unlike you that's prepared throws parts in,I'm long enough at this not to believe everything I see on a cheap code reader.
So replace the sensors,repair the wiring,screen fault cured.Not so sure the car will be any better.Hence the point of my post.

Read the Ops post & think about it- 5 sec stutter,cold engine. Ok after that. Those sensors aren't reading,heater circuit or not.
Just because a fault isn't on a screen,doesn't mean it doesn't potentially exist.
When you get a little more experience,you'll understand that.

BavarianCare

Dirty Nails wrote: »

Post 4 Should have said open loop instead of closed loop. That's all I'm giving you so your Shouting rant is after landing on it's arse.

It's heater circuits faults so nox or o2,the principals are the same.

Unlike you that's prepared throws parts in,I'm long enough at this not to believe everything I see on a cheap code reader.
So replace the sensors,repair the wiring,screen fault cured.Not so sure the car will be any better.Hence the point of my post.

Read the Ops post & think about it- 5 sec stutter,cold engine. Ok after that. Those sensors aren't reading,heater circuit or not.
Just because a fault isn't on a screen,doesn't mean it doesn't potentially exist.
When you get a little more experience,you'll understand that.

:):):)
Ok, I'll try to get more experience

Your post was misleading and factually incorrect.
Then you follow up by using a different system to highlight why you were STILL factually incorrect.

Now, the principle of closed loop vs open loop on NOx vs O2 are actually not the same. They provide totally different functions...

Falling on my arse

OP - when I said professional, I didn't mean this, ahem, [INSERT WORD HERE]

BavarianCare

Dirty Nails wrote: »

Post 4 Should have said open loop instead of closed loop. That's all I'm giving you so your Shouting rant is after landing on it's arse.

It's heater circuits faults so nox or o2,the principals are the same.

Unlike you that's prepared throws parts in,I'm long enough at this not to believe everything I see on a cheap code reader.
So replace the sensors,repair the wiring,screen fault cured.Not so sure the car will be any better.Hence the point of my post.

Read the Ops post & think about it- 5 sec stutter,cold engine. Ok after that. Those sensors aren't reading,heater circuit or not.
Just because a fault isn't on a screen,doesn't mean it doesn't potentially exist.
When you get a little more experience,you'll understand that.

And - my first post:
"Sorry, but that highlights total lack of understanding.

Regarding his fault - some had wiring chafing issues at the tranny wire clamp.
But my recommendation would be to get it checked professionally"
====

How is that 'throwing parts at it'??
Where are you working?
Just in case I have friends nearby - don't worry - it's only to tell them to steer clear
:D:D

Thank you, you made my evening Ted!
x

Dirty Nails

BavarianCare wrote: »

:):):)
Ok, I'll try to get more experience

Your post was misleading and factually incorrect.
Then you follow up by using a different system to highlight why you were STILL factually incorrect.

Now, the principle of closed loop vs open loop on NOx vs O2 are actually not the same. They provide totally different functions...

Falling on my arse

OP - when I said professional, I didn't mean this, ahem, [INSERT WORD HERE]

Wasn't coming back to this tonight,was just going to bed.
Not talking about sensor function - heater circuit function.
It was your debate falling on it's arse,just hope you didn't hurt yourself.
I didn't mean to be smart with ya,but the symtoms just dont seem to stack up to the background faults stored. Just me,been caught so often over the last 40ish years,dont believe anything you're told & only half what you see.

BavarianCare

Dirty Nails wrote: »

Wasn't coming back to this tonight,was just going to bed.
Not talking about sensor function - heater circuit function.
It was your debate falling on it's arse,just hope you didn't hurt yourself.
I didn't mean to be smart with ya,but the symtoms just dont seem to stack up to the background faults stored. Just me,been caught so often over the last 40ish years,dont believe anything you're told & only half what you see.

You're still wrong with your explanation Ted.

You said closed loop Ted

BavarianCare

Anyhoo, I've to put a S54 back together in morning so nighty night...

Yeah, I'll get back to you when I've more experience on BMW

Perhaps you'll give me a job

Cheers for the laughs

hurikane

OP, any chance you’d let the 2 lads have the car and let them to diagnose? neither will be happy until they get to the bottom of it.

Dirty Nails

BavarianCare wrote: »

You're still wrong with your explanation Ted.

You said closed loop Ted

You made me log in again.
Piss off,I'm going to bed.