BMW F11 530D faults after tune (25C800 exaust gas pressure sensor diesel particulate filter: Sensor drift out of balance and 245400 particulate-filter system: minimum differentieal

Dear Experts,

About a month ago my BMW F11 530D is tuned and in addition asked for closing the EGR valve during normal operation. I monitored the EGR valve physically and with software and it only opens now during regeneration.

The problem is that I now get 2 errors in ISTA which I never had before.

25C800 exhaust gas pressure sensor diesel particulate filter: Sensor drift out of balance 245400 particulate-filter system: minimum differential pressure undershot

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If I start with the last one: minimum differential pressure undershot

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It’s stated that the problem could have something to do with the exhaust gas pressure sensor and that there would be additional errors concerning this sensor. This is the case: Exhaust gas pressure sensor drift out of balance.

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This error pops up when there is a difference of 60mbar between ambient pressure and exhaust gas pressure before diesel particular filter.

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If I look at the sensors there is a small deviation but no extremes. The difference is max 22hPa (=mbar).

In addition I did an exhaust gas pressure test:

With the engine cold the sensor gives me negative values:

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With a warm engine no negative values:

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Before the tune I never had problems concerning the DPF.

Do you guys know how to go from here? Can it have something to do with the tune? Maybe less pressure somehow? Could it be coincidence that the exhaust gas pressure is broken?? I don’t think it makes sence replace the sensor because it almost reports the same value as ambient pressure. Although it reports negative values during exhaust gas counterpressure test.

In addition I reset adaptations of the sensors without any success.

Thanks in advance,

R

In addition I found this.

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The volumetric exhaust gas flow is greater....

Can this have something to do with the tune?

Dear Altin,

Thanks for the answer. Can you tell me how to flash my DDE to a newer I-Step version. I use ISTA-D for diagnosis and E-Sys for coding. Or should I just leave this at the tuner

Cheers,

Ok thanks wouldn't do this for now than. Is this a known issue concerning tunes of maybe when disabeling the EGR valve during normal operation?

Could It also be a problem in the DDE ambient pressure sensor because that one is measuring lower in comparison to the other sensors? Do you change baseline characteristics or can you even change baseline characteristics of this sensor with a tune?

In addition I was thinking something I don' understand:

- During exhaust gas pressure sensor test the exhaust gas pressure sensor before diesel particular filter gives normal values (see screenshot with green bars)

- During a cold engine the exhaust counter pressure test gives negative values. In ISTA is than mentioned that if values below 0 are reported you should renew the exhaust gas pressure sensor

I don't get the discrepancy between these two. Can the sensor still be faulty if it gives normal values in the exhaust gas pressure sensor test? Hopefully I make my question clear

Will ask the tuner to reflash the original file and see what happens. Keep you guys up to date.