HELP!!!! Inactive Suspension that wont go back up...

[gelafont]

i'm in a dire need of some help and suggestions here. I have an 03 X5 4.4 with the full active suspension w/ button on left side steering. Over the w/e I had my friend changed the two front rotors and brake, while on the lift I also had him checked this funny noise coming from the driver side rear wheel driving. This noise is not a squeaky sounds, nor a wu wu sounds, but more like a peck, peck, peck sounds that gets louder and constant as speed increased, and it's only coming from that single driver side rear tires. To replicate the noise, he had me start the car on the lift, and shift it to drive to replicate noise. While accelerating on the lift, i noticed all the lights started to come on the display includind the "Inactive suspension" message and a "max speed limit" message with a 35 or 45mph. I told him about it and disregarded the message and continued with the testing by taking the back tire off (accelerated some more, all messages are persisted) and finally narrowed it down and concluded the rear noise is coming from the rear wheel bearing, and it's going bad.

After putting the car back down from the lift. We noticed it went all the way down, and literally sit on the tire. Expected the car to go back up as usual, I drove it around slowy, all the light eventually went off, except for the inactive suspension message, and there were no green light showed on the left side steering button. We checked all related suspension fuses--glove compart and rear trunk (no blown fuses), unplugged battery for hours, drove it around again. Despite all efforts, the car is determined not to go back to normal level, the air pump won't buldged. It still sits on the tires, and wont go back up.

Any help and or suggestions would be greatly appreciated before i resulted to go to the dealer and get charged an insanely hourly charges to just reset or reprogram this thing. tks in advance!!!

[James 4.8is]

Well, it looks like we’re on the same boat! Went for a 4wheel alignment and after that I have the same message in my display tried all the fuses. All are ok, relay in back ok, but came across there is another relay under the air supply tank under the spire tire. Will be checking that today! If ok there is only one thing left. The ECU AIR SUPPLY CONTROL UNIT ($800 white box) in back where the spear tire is. Will keep you informed! P.S. Did you get yours fixed and if so, what was the problem?

[TriX5]

Did you check if there is 12 V going to the pump? There is a white plug on the pass. side of the trunk. Take your spare tire out and remove the plastic cover so that you can get to the plug with a DVM.

There are a couple more people who have a problem similar to yours on the board. None have solved it yet but for at least one guy the ride height is maintained, he just cant go to the high or olow setting.

I would first check voltage and open the pumpkin to seeif the compressor is operational.

[James 4.8is]

Well, my friend. Just spent the last couple of hours ripping apart the back of my X5 trying to hunt down the problem with the air suspension. Checked the high amp fuses. All are ok. Checked the black relay (Under the compressor on the right side of the battery) it seems to be ok. Now it looks like a trip to BMW! (A wallet emptying visit!) Got a strange feeling it’s the little white box (ECU Air supply control unit)!!! Damn it!!!

[TriX5]

Wish you good luck! Judging from the threads here dealers have not been all that successfull at resolving issues around the air suspension.

What stumps me is that the system pops up with "Airsusp. Inactive" on my 4.4 (rear only) from time to time but nothing is wrong and I ignore it.

On 4.8 the pump was clearly not running and the LF was low by an inch, causing real scary problems under braking and the system is completely silent..... There seems to be no pressure sensor in the system which is odd as loss of pressure could cause severe handling problems. I just don't understand the logic of how it behaves.

[gelafont]

Sorry for the late response. I tried just about everything you guys did there. it was to no help. So, I took it to the dealer and explained exactly what went wrong and for them to clear and reset the module. They came back telling they tested all individuals components and all are okayed except for the module that is unresponsive. And it needed to replace for them to fix. They quoted me $989 for the ECU II module plus labor and to reprogram it which would total for $1400 and done--btw the module costs cheaper from Alabama dealer. I needed a second opinion, I declined the work with the stealer--paid the 200+ for diagnostics, yea they claimed they put more hours; and took the car back and have my friend scan it with an aftermarket tools. After many attempts, he was able to clear/reset the ECU module--pump kicked in, and pumped all 4 airbags, the message from dash is cleared, and the suspension button is lit and at Normal level. I was able to raise/lower it. However, I noticed the passenger rear one is not fully back to normal. I suspected that rear bag may have pinched from the back and forth driving from the stealer.
I will keep you guys posted... tks all!!!

[James 4.8is]

Found something very helpful.
Found this on: http://wds.spaghetticoder.org/
The 2 links:
http://wds.spaghetticoder.org/en/zinfo/RDO53EHCIIABGL.htm

http://wds.spaghetticoder.org/en/svg/sp/SP0000016415.svg?m=e53

[James 4.8is]

Sounds like a winner to me Gelafont. I'll give that a try before I go shucking out all that cash to BMW! Thanks for the good tip! If that works for me too I'll buy you a beer!

[igosal]

This is great info.... Thanks a lot James 4.8is....
For my X5, I found this info:

Vehicle inclination
There can be a wide variety of causes for a vehicle inclination. The causes usually lead to an entry in the fault memory of the control unit or to a CC message in the instrument cluster.

Causes for vehicle inclination
Sensor causes
Checking of the sensor system according to instructions in the adjacent diagnosis test module.

Mechanical causes
Sensor linkage (position, defective)
Sensor holder (position)
Securing clip of the sensor linkage (position)

Leaks as causes
Leak in the lines
Leak in the valve block
Leak on the spring strut

Electrical causes
Water in the connector (corroded pins): With this fault, a creeping inclination begins, as the signal slowly drifts away.
Short circuit in the 2-axle air suspension system (but this is normally stored by the control unit as a fault and detected via diagnosis).

System-specific causes
Opening a vehicle door during a change in the ride height (vehicle at a standstill) can cause a vehicle inclination.
Rapid forces being exerted from the outside (attaching a trailer, fast loading or unloading) can prevent regulation.
Tolerance bands with ignition on: +/-10 mm to height value from TIS. Note: In the case of the front axle, the mean value of both heights counts.
Tolerance bands with ignition off: +15 mm/-20 mm to height value from TIS. Note: In the case of the front axle, the mean value of both heights counts.
Temperature deactivation

Originally Posted by James 4.8is

Found something very helpful.
Found this on: http://wds.spaghetticoder.org/
The 2 links:
http://wds.spaghetticoder.org/en/zinfo/RDO53EHCIIABGL.htm

http://wds.spaghetticoder.org/en/svg/sp/SP0000016415.svg?m=e53

[igosal]

Also found:

2-axle air suspension
The 2-axle air suspension combines an automatic load compensation on the front and rear axles with the possibility for the driver to set various vehicle levels.

Brief description of components
Control unit
The control unit activates all the valves, the compressor and the LEDs. The control unit activates all the valves, the compressor and the LEDs. To achieve this, information from the height sensors, the button, the K bus and the CAN bus is used.

Air supply system
These elements are fitted beneath a sound-damping cover. These elements are fitted beneath a sound-damping cover.

Height sensors
The suspension travel at the individual wheels is determined by measuring the relative movement between the wheel and the body. Angle of rotation sensors are used to achieve this.

Rocker switch with LEDs
The driver has a rocker switch with up/down function, which can be used to change the height level. Three LEDs are located beside the rocker switch to indicate the current height level.

Accumulator/valve unit
The accumulator/valve unit is located behind the right-hand sill, beneath the underbody panelling. The accumulator/valve unit consists of: the solenoid valves, the pressure accumulator, the pressure accumulator sensor and the pressure accumulator valve.

Main functions

System function of 2-axle air suspension
The 2-axle air suspension automatically regulates load changes on the front and rear axles. In addition, the driver can set three different heights, for example to achieve greater ground clearance in off-road driving.
There are three different heights:
- Standard: normal driving height
- Off-road: increases compared to normal driving height
- Access: lowered in relation to standard, for entry/exit, loading/unloading
In every case, the current height is indicated by the corresponding, permanently lit LED. As soon as the driver specifies a new target height by pressing the button or a change is initiated automatically by a certain driving condition, the LED of the current level remains lit and the LED of the target level flashes. When the new level is reached, the LED of the last level goes out and the LED of the newly reached level lights up permanently.
A special case is advance selection of the Access level while driving: the Access LED flashes and the LED of the original level lights up permanently. However, this does not mean that adjustment has started. This only takes place when the corresponding speed threshold that permits the Access level is reached or the speed falls below this threshold.
As soon as the ignition is switched on (terminal 15), downward level changes requested by the driver are possible. Upward changes of the level - and thus filling of the accumulator - are only possible when the vehicle engine is running.
These functions are enabled by activation of a compressor and various valves in the air supply system and the accumulator unit.
The control unit receives information of the current height of the vehicle from four height sensors. The pressure in the pressure accumulator is also registered by a sensor. The evaluation of various signals on the CAN and K buses enables recognition of driving situations and activates corresponding adjustments.
The interface to the driver consists of a button and corresponding LEDs. The 2-axle air suspension control unit can also activate text messages in the text display of the instrument cluster. The system is activated by the front axle signal and can thus become active before the vehicle is started.

Service functions

Height calibration or offset by DIS/MoDiC
As is familiar from the 1-axle air suspension system, a height calibration must also be performed for the 2-axle air suspension under certain conditions, e.g. following replacement of a height sensor. All air suspensions can be lowered or raised individually. The required activations are performed using the corresponding routines in the diagnostic program for the 2-axle air suspension. When the vehicle has reached the correct height (see TIS for height values), the height offset is performed. In the case of the 2-axle air suspension system, the offset function is performed on an axle-by-axle basis, i.e. first on the front axle and then on the rear axle. Before the offset command is executed, the height should be rechecked.

Operational test after part replacement or repair
On the 2-axle air suspension, the function of the components concerned must be checked with the corresponding service function after repair or part replacement.