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
![Image]()
If I start with the last one: minimum differential pressure undershot
![Image]()
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.
This error pops up when there is a difference of 60mbar between ambient pressure and exhaust gas pressure before diesel particular filter.
![Image]()
![Image]()
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:
![Image]()
![Image]()
With a warm engine no negative values:
![Image]()
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
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
If I start with the last one: minimum differential pressure undershot
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.
This error pops up when there is a difference of 60mbar between ambient pressure and exhaust gas pressure before diesel particular filter.
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:
With a warm engine no negative values:
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
