2002 L322 air sus height sensors/calib

Hi all,

Pulling my hair out over this now.

Began few weeks back, no issues with air susp at all..... Until rear height sensor snapped.

No problem, had 2 brand new rear unbranded cheap eBay £35 for the pair In the garage in the parts box, fitted both sides as the other side was on its last legs too. Been meaning to fit these for about a year as the MOT tester discretely said they were deteriating.

So when the sensor originally snapped..... Fault was a 'articulation validity' Which you would expect.

After new sensors fitted, one side was right up in the air at its natural stance, as requires calibration.

So ive calibrated the whole air suspension, front and rear, taking hours using the legend Saints L322 height chart as well as RSW All comms got them to within a couple of mm as it should be.

She Sits fine, adjusts into all heights absolutely fine on the spot, but drive off and the frigging dreaded fault appears after a couple of hundred yards up the road 'Articulation validity'

Now....if I plug in my Hawkeye diagnostic.... Go onto live data for the air susp....it reads the height sensors current position in MM.

The readings are somewhat different.....For example.

Front left -25mm
Front right. +30mm
Rear left +33
Rear right -25

The car is sitting dead level (give or take a MM or 2) so within the tolerances.

What is going on? Where is the BCU getting the readings from?
The Hawkeye readings were always different (fairly substantially). Before changing the rear sensors.

Any ideas/thoughts?? I was umm'ing and arrr'ing if it was the cheap sensors.....but they read fine and adjust as they should.

Thanks in advance

cheap and L322 seldom go well together,

If they're Chinese knock offs they might not be sending the correct info to the BCU.

robhew86 said:

Hi all,

Pulling my hair out over this now.

Began few weeks back, no issues with air susp at all..... Until rear height sensor snapped.

No problem, had 2 brand new rear unbranded cheap eBay £35 for the pair In the garage in the parts box, fitted both sides as the other side was on its last legs too. Been meaning to fit these for about a year as the MOT tester discretely said they were deteriating.

So when the sensor originally snapped..... Fault was a 'articulation validity' Which you would expect.

After new sensors fitted, one side was right up in the air at its natural stance, as requires calibration.

So ive calibrated the whole air suspension, front and rear, taking hours using the legend Saints L322 height chart as well as RSW All comms got them to within a couple of mm as it should be.

She Sits fine, adjusts into all heights absolutely fine on the spot, but drive off and the frigging dreaded fault appears after a couple of hundred yards up the road 'Articulation validity'

Now....if I plug in my Hawkeye diagnostic.... Go onto live data for the air susp....it reads the height sensors current position in MM.

The readings are somewhat different.....For example.

Front left -25mm
Front right. +30mm
Rear left +33
Rear right -25

The car is sitting dead level (give or take a MM or 2) so within the tolerances.

What is going on? Where is the BCU getting the readings from?
The Hawkeye readings were always different (fairly substantially). Before changing the rear sensors.

Any ideas/thoughts?? I was umm'ing and arrr'ing if it was the cheap sensors.....but they read fine and adjust as they should.

Thanks in advance

Click to expand...

Does it sit correctly at all heights?

Datatek said:

Does it sit correctly at all heights?

Click to expand...

Yes Keith

robhew86 said:

Yes Keith

Click to expand...

I would say that rules out the sensors. The readings may indicate a bug in the Hawkeye software, if you ignore the + & - signs the readings look OK so the fault may lie elsewhere. May not be relevant, but have you done the lock to lock reset? have you checked the battery voltage with the engine running at 2K rpm?

Datatek said:

I would say that rules out the sensors. The readings may indicate a bug in the Hawkeye software, if you ignore the + & - signs the readings look OK so the fault may lie elsewhere. May not be relevant, but have you done the lock to lock reset? have you checked the battery voltage with the engine running at 2K rpm?

Click to expand...

Yes I did do the lock to lock reset originally, but other warnings came on too not just 'air susp inac' fault.

Battery is all fine as is charging it etc.
Bloody thing!

robhew86 said:

Yes I did do the lock to lock reset originally, but other warnings came on too not just 'air susp inac' fault.

Battery is all fine as is charging it etc.
Bloody thing!

Click to expand...

Been a lot of rain recently, water ingress? You have 14.7 volts or more at the battery?

Datatek said:

Been a lot of rain recently, water ingress? You have 14.7 volts or more at the battery?

Click to expand...

Nope, no evidence of any water ingress anywhere and the battery is fine too

The sensors - as fitted - would be one side is upsdie down and the opposing opposite corner is the right way up....when I say upside down and right side up, they are fitted correctly...

So one would read in the minus (as it is upside down) and the other in the positive (as it is the right way up).

Saves making two different sensor internals for each side/corner...so the system reads one in + and one in -...if that makes sense.

Saint.V8 said:

The sensors - as fitted - would be one side is upsdie down and the opposing opposite corner is the right way up....when I say upside down and right side up, they are fitted correctly...

So one would read in the minus (as it is upside down) and the other in the positive (as it is the right way up).

Saves making two different sensor internals for each side/corner...so the system reads one in + and one in -...if that makes sense.

Click to expand...

That's interesting Ant, yes and does makes sence too!

When the live reading positions of the height sensors are sent to the BCU, is this from those readings the Hawkeye is giving me? As the fronts (not touched sensors) are a little out,

I.e Front left +25
Front right -40

Or are the live readings from the sensors when calibrated essentially levelling the whole car dead level (in the BCUs memory). .....so regardless of the live readings of the Hawkeye it's not confusing the BCU, if that makes any sence?