SelfLevel Sus Inactive cause?

[TerminatorX5]

there is an error in the system somewhere, otherwise, how would the display know to show the error in the first place. The error is definitely in the SLS module, which reports it to the cluster via the ibus telegram, and the cluster displays the verbiage from the SLS module (the verbiage for SLS is not stored in the IKE or GM or LCM, it is supplied from the SLS module). INPA should register some error - have you checked the shadow memory too? Are you able to raise/lower the car using the INPA?

[TerminatorX5]

here is some info from the WDS:

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.

[GSXRliterbikz]

Originally Posted by TerminatorX5

there is an error in the system somewhere, otherwise, how would the display know to show the error in the first place. The error is definitely in the SLS module, which reports it to the cluster via the ibus telegram, and the cluster displays the verbiage from the SLS module (the verbiage for SLS is not stored in the IKE or GM or LCM, it is supplied from the SLS module). INPA should register some error - have you checked the shadow memory too? Are you able to raise/lower the car using the INPA?

I can raise and lower it with inpa. Pump works fine if turned on with inpa. But it won't run on its own. Shocks hold air indefinitely too, so no leaks.
I did look at shadow memory, still nothing.
Guess I'll take another look though.
When I got the car, it had the wrong cluster in it that wasn't coded. I thought that was it, so I coded it and entered the correct zcs code into it, still no change.
And it's only a single axle air setup.

[bcredliner]

Acknowledging reading codes can pinpoint the core cause of many issues, they are often ineffective resolving SLS Problems. Most stabs (throw new parts at it) at solving the problem are costly. I don't ever recommend that as an approach anyway. By the way, SLS and TPS lights can both be on with cause being the control module. That is one of those potential causes that is expensive to try and see if it is a fix.

Some common sense no cost checks that you might want to try if you have not already done so:

I don't know what is meant by no indication the sensors were bad. I would check the sensors for a broken wire or corrosion as that is easy to do. I would check if one of the sensor levers has turned over which can happen when the suspension is fully extended as it could have been depending on how you define off roading.

I would listen to the pump and see to see if it is stopping and starting or continues to run. There can be a leak and the vehicle still stay at normal height as long as the compressor output can compensate when the system is active.

I would do the soapy water check of all air bags and line connections looking for leaks even though the system holds air indefinitely, however long indefinitely is to you.

[kodomokid]

Originally Posted by TerminatorX5

i've had SLS message, i have reset it several times as I did not have time to mess with it, until one day, instead of resetting, i looked into INPA readout, it said pressure in reservoir was not plausible, or something to that effect... that type of error pointed to specific issue that could be rectified with the repair kit, took me about an hour to get it fixed, no error since then...

You may consider the INPA software package that RFaber mentioned, from the romanian guy - very good investment, as the errors come with explanation (that explanation sometimes calls for more explanation!!)...

Thanks for the tip. The repair kit that you are referring to, is it for the compressor? I did a search and that is the majority of the repair kits on Ebay.

[Ricky Bobby]

The repair kit is for the compressor seal, over time it wears out and although the system is functional it will throw an error for the accumulator not filling within spec.

Use the bagpipingandy repair kit on ebay if purchasing, he makes the original and best quality replacement seal. And you'll have to reset the faults using DIS after repair.

[kodomokid]

Originally Posted by Ricky Bobby

The repair kit is for the compressor seal, over time it wears out and although the system is functional it will throw an error for the accumulator not filling within spec.

Use the bagpipingandy repair kit on ebay if purchasing, he makes the original and best quality replacement seal. And you'll have to reset the faults using DIS after repair.

Awesome! Thank you! Better than replacing for just worn seals, if that is the source of my issue. I will report back my findings as we work through it.

[kodomokid]

OK update. Was a bad rear left height sensor. Replaced it and did a recalibration to factory settings and, knock on wood, has not had the error since. I am on my 2nd week of error free. Now on to the next error that I am sure will come up in a few months. Joys of modern sensor dependent cars.