Hello guys,
i tried to find solution but with no sucess.
Perhaps someone of You guys have any clue what for God sake means Fault "Distortion plausibility" and where should i look for a problem.
After repairing front height sensors now my friend FFRR showing "Air suspention inactive" and fault like above.
i'm using BMW DIS to read/delete codes, fault looks like below.

Thanks in advance for any sugestions!

Quote:

Fault Detection by the ECU
The ECU thinks it can directly detect certain kinds of faults, termed hardware faults, including sensor hardware, valve hardware, sensor and actuator supply, bus failures, ECU hardware errors. The ECU also tries to second guess other faults indirectly. This activity is called plausibility checking, and includes the following checklist according to the workshop manual:

1. Average height does not change correctly, or changes too slowly.
2. Suspension moves in the wrong direction.
3. Reservoir pressure does not increase when reservoir filling requested, does not decrease when reservoir used to lift vehicle, does not decrease when reservoir is vented, or varies too much when inactive.
4. Compressor temperature increases when compressor inactive, or does not increase when compressor active.
5. Energy' used to change height of corner is too much, or long term filtered height does not reach target.
6. Sensor signals floating, inconsistent (eg signal on one side of axle is varying but other side remains static), or indicating constant articulation when moving.


ECU Reaction to Faults
Whenever a fault occurs, if the ECU can determine the ride height and the vehicle is not above standard ride height, the driver will be notified via a 'AIR SUSP. INACTIVE' message in the message centre. If the ECU cannot determine the height this message is accompanied with an alternating 'MAX 35MPH' message.

In terms of restricting EAS function, the reaction of the ECU to faults (although highly irritating and overly conservative) is at least somewhat more flexible than on presious models. The ECU divides faults that it thinks exist into "major" and "minor" categories, and its reaction in terms of restricting system functionality varies accordingly.

Minor Faults:
If the ECU decides there is a "minor" fault, it will freeze ride height but continue to try and level the vehicle at the current height. However it will not respond to requests for changes -- except manual or automatic requests for a return to standard height from some other height. The shop manual notes that if the ECU is able to level the vehicle to the current ride height, the control switch LED's will display the current ride height. When the vehicle returns to the standard ride height and further height changes are disabled, the 'HOLD' LED in the control switch will be permanently illuminated.

Minor faults are defined as follows:

1. Most height sensor hardware and plausibility problems
2. Failure of the reservoir solenoid valve
3. Failure of the Cross Link Valve(s)

If a height sensor fails, some loss in system functionality is understandable. However in the case of failure of the reservoir valve there is no good reason why the system should not be allowed to continue to operate normally, using the compressor to raise the vehicle height and bypassing the reservoir. If a cross link valve fails, there is no reason that should affect the functionality of the system other than disallowing cross-linking. Unfortunately, the designers have again taken the approach of excessive conservatism which is especially annoying for the real off road user.

Major Faults:
Major faults are defined in the sho manual as:

1. Compressor faults
2. Plausibility errors – for example:
Average height does not increase when lifting and the vehicle is moving. This could be caused by a compressor fault or a fault in the reservoir valve.
Reservoir pressure decreases when filling requested. This could be caused by a leak in the common gallery in the valve block or connecting pipe.

No mention is made of faults actually likely to occur during four wheeling, like having a spring punctured by an off road obstacle(this happened to me on my 4.0SE). As on previous models, the ECU has a fairly knee-jerk reaction to these faults. All the control switch LED's will remain unlit.

The ECU reaction to major faults is to abandon any further attempts to level the vehicle at the current height and to attempt to return it to standard height as soon as any manual or automatic height change request is received. If it can achieve standard ride height, it will freeze at this height and refuse to respond to further height change requests.