So... quite a few of us have mentioned an error that appears in INPA/DIS etc. that indicates that the Electronic Brake-Force Distribution (EBV) system is in an error state - time to have another look at this perhaps?
X5only started a
good thread on this a few years back but nothing was resolved.
One "fix" involves a code change to disable the EBV system. Sure, the error message is gone and if that satisfies your OCD, that's great. But the EBV isn't fixed...
There's been a suggestion that the yaw sensor is partially responsible but a few folk have changed this with no change in the EBV error state.
I've spent some time looking into how the EBV system works and while I'm not 100% how proportional brake modulation is achieved on the E53 platform, BMW do mention the following in one of the tech training manuals (on brakes)…
Electronic Brake Proportioning (EBV)
The Electronic Distribution of the braking force (EBV). Will adjust the braking force to the rear wheels based on the vehicle’s loading to maximize the braking force at all wheels.
The control module monitors the wheel speed sensor inputs, when the brakes are applied, to determine vehicle loading. The control module compares the rate at which the front and rear axles are slowing down.
If the rear axle is slowing at a rate similar to the front it indicates that the vehicle is loaded and more braking force can be applied to the rear calipers to stop the vehicle.
If the decel rate of the rear wheels is far less than the front, it indicates a lightly loaded vehicle. At this point, if the same braking force were applied to the front and rear axles, the vehicle would become unstable.
If this difference exceeds the threshold values programmed in the control module, EBV is activated. The control module will cycle the inlet valves to the rear brakes to regulate the braking force.
From this description, it sounds as if the only sensors used for EBV processing are the wheel speed sensors.
An old Toyota Previa I used to own had a mechanical brake proportioning system, using an arm on the rear axle to control a brake valve that reduced rear brake pressure when the rear suspension unloaded...
Simple but effective... and easier to diagnose than the electronic version on the E53.
In my own case (on my E53) after owning the car for three years, scanning it regularly with INPA as part of my service regime, I never saw any EBV errors... until one day after I ran a scan using DIS. I needed to reset the oil wear adaptations on the VTG module, after changing the transfer case fluid, and I ran DIS, performed a full scan and bang, EBV error popped up, in the exact same manner as described by X5only in his 2011 thread.
And now I have the error in INPA too, every time I scan the car...
I have no other errors and everything appears to function as it should. While I'm not actively chasing this error, I know
LVR is chasing down a red TPMS light and is looking at the EBV error as being possibly related and I figured rather than clutter up the other threads, this issue deserves it's own thread (again!).
