[hpopmds]

Hi to all. Can you help, please?

My car's backpressure values are this:

At idle = 24hPa (i know it's too high)

Engine off = 19hPa (Shouldn't it be 0 (zero)?)
Engine off + sensor pipe off = 19hPa
Engine off + sensor pipe off + sensor plug off = -422hPa

Is it normal that the sensor returns 19hPa when disconnected from the air pipe?
Shouldn't it be 0 (zero)?

Thanks. I need to know if i buy a new sensor or if it can be done some adaptations in the ECU.

[Enabled]

19 and 24hPa is really really small.

Are you having any actual issues?



If your location's barometric pressure is 1019mbar, then you will easily show 19 hectopascals on backpressure sensor.

[hpopmds]

Originally Posted by Enabled

19 and 24hPa is really really small.

Are you having any actual issues?



If your location's barometric pressure is 1019mbar, then you will easily show 19 hectopascals on backpressure sensor.

Hi Enabled

I got this values with "BTools" app (see file attached).
My problem is that the backpressure values are so high that the car thinks there's too much soot and starts regeneration every 20km, or less
Note that the RPM are 0, and the backpressure is 19hPa. (24hPa at idle - 800 RPM)
I asked if that values are normal, although i did compare them with another similar car, and the backpressure with engine off was close to 0 hPa, and 4hPa at idle.

So, my questions are:
a) Should the backpressure be 0 with engine off?
b) If yes, is the sensor faulty or it may be some bad adaptation values on the ECU?

Thanks again

[Enabled]

I would use original tools like INPA or ISTA to read these just to make sure.

Ash mass of 0.0 is unusual, like someone registered a dpf replacement?

Soot mass of 46g is high.

[hpopmds]

Originally Posted by Enabled

I would use original tools like INPA or ISTA to read these just to make sure.

Ash mass of 0.0 is unusual, like someone registered a dpf replacement?

Soot mass of 46g is high.

The car is fooling us. We thought that the DPF was clogged, was sent to a specialized cleaning workshop, and they were honnest and refered that the DPF was fine.
So, the next step was to reinstall and reset the DPF. That's why the ash is 0.
Unfortunatelly, we still have very high backpresure and consequently high soot values (although there's not really so much soot), and too much frequent regenerations.
Since this reset of the DPF, i am waitng that the values are automatically adapted by the ECU, but as i see no progress, (tomorrow is monday), i think i will risk and buy a new sensor to replace.

[Enabled]

Ideally you should read the differential pressure sensor readings, before and after.

The backpressure sensor is a minor part of this.

[hpopmds]

Originally Posted by Enabled

Ideally you should read the differential pressure sensor readings, before and after.

The backpressure sensor is a minor part of this.

As far as i know, this car has only 1 pressure sensor, located before the DPF. (see that sucker sensor in the image attached - it has only 1 connection for a rubber hose to the DPF).
I think it mades the calculations with the atmospheric pression (or other).
In "Btool expert" the value of differential pressure is always 24hPa, always.
And that's why i assume that the backpressure at "engine off" (or with the rubber hose out) should be 0. (but i'm no expert).

[Enabled]

Can you identify your car, last 7 of VIN?

The US N47 are like the EU6, which have a differential pressure sensor and a backpressure sensor as well.

I do think that a sensor replacement may be a good idea. Did that value change if you stepped on the accelerator?

[Enabled]

Even the EU5 N47 has 2 sensors, with the simple front DPF sensor.

https://www.realoem.com/bmw/enUS/sho...diagId=13_1474
You should he able to use the two readings (with INPA or ISTA) to compare to see if they are equal.

How do you know which sensor btools is reading?

[hpopmds]

Originally Posted by Enabled

Even the EU5 N47 has 2 sensors, with the simple front DPF sensor.

https://www.realoem.com/bmw/enUS/sho...diagId=13_1474
You should he able to use the two readings (with INPA or ISTA) to compare to see if they are equal.

How do you know which sensor btools is reading?

My car is a 2013 F31 318d.
Yes, that backpressure value changes on pressing the accelerator when driving.
Also changes if i take the hose off or if i take the plug off (sensor nr 5), with the engine on.
But, as the 2 sensor work in pair, they might have some dependency, and one affects the other.

Tomorrow i will try to locate and check sensor nr 7.

[hpopmds]

Well, i did inspect sensor nº7 (part nr 13628507634) and clean it. Also found that the pipe was really dirty, so i cleaned it too. I also did a delete on adaptation values on ISTA.
Till now i see no difference, i still get too much backpressure
Is there a way to easily test this sensor nr 7? (maybe with a multimeter)

EDIT: Already ordered the 2 sensors. In the next 2 weeks hope i'll get results.

[hpopmds]

UPDATE: Sensors replaced, adaptations reset.... No changes

Engine...........COLD...........HOT
0 RPM...........4mbar.........19 mbar
830RPM........16mbar........24mbar

I think this doesn't make sense. The pressure should be zero with engine off, in all ways, hot, cold.
Although the DPF cleanning company said the particulate filter was not clough and it doesn't need cleanning, i think next step is to change it/clean it, and maybe repro.

I am getting out of options! The car is in frequent regens

[RobbPT]

Hi Mate!
Did you find what the problem was? I getting the same problem as you on my 114d.

[Ravi1017]

Hey!
Did you solve the problem?
I have the same issue

Thanks for your helping!

[RobbPT]

Hi!

On my case, i solve the dpf backpressure wierd readings by replacing the ecu with a used on do to the fact that the ambient pressure sensor inside the old ecu that is used in the dpf backpressure readings was reading a very low ambient pressure. In my garage I was getting 994mbar readings and with the "new" ecu I get 1006/1008mbar readings which is a value very similar to the one read by the dpf backpressure sensor when the engine is turn off.

What BMW doesn't tell in clear words is that the dpf backpressure value shown on the dde menu of euro 4 and euro 5 cars with the one hose sensor is a calculation between ambient pressures measure by does two sensor that I mentioned before.

I didn't present the solution before because now i have other problem. My dpf get's clogged up really fast and in fact the car is producing to much black smoke when i test it with a deleted dpf. My lambda sensor is working ok and i think my injectors are also working ok. However, I remember that when I bought the car 3 years ago I had to replace the MAF sensor because it broke and then all the black smoke problems started.

I used a Bosch MAF because it was the same brand of the OE one. Now, with the MAF and EGR disconnected I don't get a high level of soot in 10 kms. It increased to something close to 100 kms which is more acceptable because I do short trips (around 15 kms) with a little bit of traffic.

Now I'm thing about getting a used original MAF from Ebay to test on my car.

[RobbPT]

Hi guys!

Just to give an end to my story and help other people with the same problem that I had.

I was wrong thinking that the problem was related with MAF or EGR. My real problem were my injectors. I found a function on ISTA that would test the debit of each injector and indicate which one of them would need to be replaced.

According to ISTA the car had 2 faulty injectors with excessive debit (At the end of this story with the replacement of the 4 injectors and coding them, I found that this function isn’t that accurate because with the 4 new injectors ISTA sometimes indicate that they have a very high debit and one or two would need to be replaced which isn’t the case because they are already new).

I decided to take all the 4 injectors to a shop that would test them. I end up knowing that they supposedly had a lack of debit which didn’t make any sense according to ISTA. At first, I replaced 2 of them and the car immediately increased the mileage between regenerations to something close to 100kms by it self, without disconnect anything. After that test I end up replaying the other two and now the car regen’s in a average between 200/250 kms which is very good considering the fact that I do a lot of 10kms trips and some city driving. I’m very happy with this closer although I think this interval can increase a little bit more after I repair my turbo (it is leaking a little bit of oil to the intake but the core doesn’t have play which is a little bit confuse though). And the other very good news is that I stop having the error related to a clogged Dpf even if I interrupt, not on purpose, a regen!

I almost forgot: I’m my case with the old injectors, my backpressure sensor would read high pressure all the time (always above 15mbar). Now I only have does reads when the Dpf is asking for a regen.

Even though it is kinda noticeable that my problem is solved I’m still monitoring the car to really understand if the problem is 100% solved. I believe it is but you know how this things are…

Now I’m just worried with the possibility of the Dpf start leaking smoke or the injectors brake again, but I need to stay positive and believe this problem is solved for good!

[armanh94]

Hi guys. Sorry for resurrecting this thread. I recently had a ‘drivetrain error’ on my idrive on my 640d. Fault codes showed to be issues with dpf and dpf backpressure sensor and car was also in limp mode. The Backpressure readings were extremely high (200hpa) on idle and around 750hpa on 4000 revs before changing the sensor and after changing the sensor idle was down to 20hpa and 70hpa when at 4000 rpm. These are readings when the car is stationary in park. I believe the second readings are normal however when im driving and ‘flooring it’ does anyone know what readings should be showing? At one point I saw a reading of 400-600hpa with foot planted. Is that normal? Does anyone have any idea of what what normal differential pressure readings must be. Car is driving fine now but unsure if my backpressure is still high when boosting.

[RobbPT]

Originally Posted by armanh94

Hi guys. Sorry for resurrecting this thread. I recently had a ‘drivetrain error’ on my idrive on my 640d. Fault codes showed to be issues with dpf and dpf backpressure sensor and car was also in limp mode. The Backpressure readings were extremely high (200hpa) on idle and around 750hpa on 4000 revs before changing the sensor and after changing the sensor idle was down to 20hpa and 70hpa when at 4000 rpm. These are readings when the car is stationary in park. I believe the second readings are normal however when im driving and ‘flooring it’ does anyone know what readings should be showing? At one point I saw a reading of 400-600hpa with foot planted. Is that normal? Does anyone have any idea of what what normal differential pressure readings must be. Car is driving fine now but unsure if my backpressure is still high when boosting.

Hi!

I'm sorry for the late response. I believe that your problem really was the backpressure sensor because the readings that you got after replacing it are normal but tipical from a dpf that needs a regeneration.

I don't know the backpressure values during heavy accelaration but if there is no error codes, everything should be fine!

[jinjur]

What is your atmospheric pressure reading buddy?

I only ask as with these single pipe back-pressure sensors, the system measures the difference between the back-pressure sensor and the atmospheric pressure to work out what the actual back pressure differential is.

I recently (will link thread) worked out that my atmospheric pressure reading was way too low, usually around 940hPa and with my back-pressure sensor (single pipe, like yours) working and reading around 1010hPa, you can see that my differential was way higher than acceptable at around 70hPa at cold idle.

So while nowhere near your numbers, check your atmospheric reading for a start and let us know.

Jeez @RobbPT...........just saw your post. Yeah, same here but much worse out. Seem to be alot of these sensors failing now. I had a local electronics company replace mine which worked.

J