Next we simply tested sensor plausibility which showed a reading of 0 m b with ignition on engine off.
Bmw dpf back pressure sensor readings.
Bmw dpf removal service bmw dpf diesel particulate filter systems seem to have blocked dpf s normally caused by faults within the ecu system whereby it fails to regenerate at set intervals due to false calculations of pressure in the dpf but also we find many bmw s won t flag up a warning until the dpf is blocked beyond economical repair.
When i do the dpf back pressure test with the just the engine running and no driving i have approx 12mbar at idle 55mbar at 2000rpm and 100mbar at 4000rpm these results are roughly half the bmw max recommended value.
A good one at idle would be 10mb or less bring revs up to about 2500rpm and less than 100mb flat out under load and 300mb max.
Active reads the back pressure of the exhaust or soot load of the filter to determine when to begin the regeneration.
Once initiated the timing of the fuel injection will alter that will result in the exhaust temperature increasing to burn the soot particles.
The 3 readings above confirm the usual 480a 481a dpf fault and exhaust back pressure faults sadly all too common.
The sensor monitors and measures the pressure with the egr valve.
The differential pressure feedback exhaust sensor or dpfe sensor is part of the vehicle s exhaust gas recirculation egr system.
You would normally measure dpf pressure in mb.
As you can seewhen looking at the back pressure result below it was non too promissing.
There are several possible reasons why a dpf could be showing a reading like this.
300mb is about 4 5 psi.
I needed to check if it was indeed blocked and the first back pressure reading showed exhaust gas back pressure at 940m b at 2 000 rpm.
This prevents the valve from malfunctioning and allowing too much exhaust into the intake manifold at one time.
While there seems to be benefits to these computer manag.