Differential pressure sensor: Error P2453 despite new sensor

Hello everyone,

A few weeks ago, the problem started with the "short to positive" error from the differential pressure sensor. A repair shop then replaced the sensor and cleared the fault. However, after 2 days, the following errors reappeared:

7347 - Diesel particulate filter differential pressure sensor
P2453 00 [173] - implausible signal

and

7346 - Diesel particulate filter differential pressure sensor
P2453 00 [237] - implausible signal

(The second error message always indicates an invalid date and an implausible speed of 255 km/h. And why are there always two almost identical messages??)

The workshop is at a loss, as the service department plans to check the (again) air pressure sensors in 2 weeks.
I have re-programmed the new sensor using VCDS via the "Adapt" menu, but the error keeps appearing.
What is puzzling me: according to the log, the new sensor has an offset of -75 hPa (!), but after the adaptation, it shows 0 hPa.
Do the sensors really have such a wide variation?
Could the sensor already be defective?

I'm attaching a log from my Roomster 1.6 (105hp), maybe someone can say something about it.

Best regards!

Have you ever logged and checked the differential pressures? It would be useful to do this under full load of 1,500-4,000 rpm in high gear. Then you can see if any noticeable differential pressures are measured.

Best regards,
Guste

I'm trying to figure out how to do this in a way that's compliant with the traffic regulations. I don't have a co-pilot who could simply operate the laptop.

udiederichs hat folgendes geschrieben:

I'm trying to figure out how to do this in a way that complies with the traffic regulations. I don't have a co-pilot who can just operate the laptop.

You can easily start logging with the laptop while stationary and then take your test drive in peace, while the log is being recorded. No need to press any keys on the laptop.

If necessary, you can delete the irrelevant lines at the beginning of the test drive later in the log. However, you can also simply leave them in. You can later see in the log how the differential pressure increases over a long period and also how the RPM slowly increases (Please record at least RPM and differential pressure).

Please do not use the laptop during the drive.

Regards,
Guste

Okay, I've logged the return trip today. I used VCDS to select measurement channels ("extended measurements") and (hopefully) identified meaningful ones (I can only guess at some of the channel abbreviations).

The CSV file can be opened and visualized with KDataScope.

If I have selected any inappropriate channels, please let me know which ones are better.

Thank you!

udiederichs hat folgendes geschrieben:

So, I've logged the return trip today. I used VCDS to select measurement channels ("extended measurements") and (hopefully) selected meaningful ones (I can only guess at some of the channel abbreviations). The CSV file can be opened and visualized with KDataScope. If I have selected any unsuitable channels, please let me know which ones are better. Thank you!

Hello,

Logging values that are constantly 0 is pointless, as is logging vehicle speed. What's important is the engine's load, specifically RPM and current injection volume.

There must also be measurable values for the differential pressure that provide meaningful data. :idea:

Have you checked the hoses on the differential pressure sensor? If two are connected and not just one... then a proper differential pressure sensor should be installed.

Best regards, Rainer

Constant zero sequences are "meaningless," of course, but I'm still not entirely familiar with the meaning of the measurement channels (not all of them are self-explanatory to me).

On the weekend, I have more time, so I can investigate this in more detail.

Hoses reversed: I will test this, I can't offer the control unit meaningless measurement values like before.

We'll see...

Result: Hoses are ok and unobstructed, the cause is the differential pressure sensor. The "new" sensor is a cheap piece and is already defective. There is no manufacturer printed on it, nor any of the common OE numbers. It smells strongly of burnt plastic.
Purchased (50€) and installed in a workshop, I will return the sensor tomorrow.
I bought a new Bosch sensor from an online retailer and installed it today. The first measurement already provided plausible (positive) values. I then initiated a service regeneration while driving and burned out the soot (the temperature briefly rose to 780°).

Hopefully, this issue will be resolved.

Best regards!

Thank you for your feedback! ☺