Thread: Height Calibration + Sensor Issue - can't calibrate

Hi guys - need some help diagnosing my issues with my L320 2011 TDv6.

I was having some issues with air suspension faults coming on over last couple of months. I would get intermittent orange suspension fault. If I go over 65km/h for over 20secs then it goes into red suspension fault mode and goes down to bump stops.

I was having intermittent issues with the rear right height sensor so I changed this (using live values and Thingdiag tool). I also changed the front right height sensor after seeing some intermittent issues on this sensor also. I have also cleaned both front and rear valve blocks - were slightly dirty but were both fine.

Symptoms -
- as above I am getting intermittent orange suspension faults
- going over 65km/h for over 20secs I get a red suspension fault and it will go down to bump stops
- if i try put the car into access height mode it will go down and then go into extended height mode almost immediately
- trying to use thinkdiag tool to do a height calibratation - i can't complete this successfully (measuring heights from middle of hubcap to wheel arch). I suspect the measurements are outside acceptable values but not sure (436mm, 435mm on front left and front right, 483 and 473 on rears).

I have taken a live screen recording of the voltages I am seeing for each height sensor. You can see below -

- Graph 0-10secs - Initially the car is at normal height at the start. Readings are flat
- Graph 10-15secs - I then put the car into access mode. Front left and Rear left voltages go up while rear right and front right voltages go down. THIS I suspect is the issue. The voltages on one of the sides is going the wrong way when the car changes heights.
- Graph 15-20secs - After a few secs the go car goes into extended height mode and you can see the voltages go the other way to what they did initially when the car when into access height mode.
- Graph 25-50secs - Then period of flat area - car is in normal height mode.
- Graph 50-70secs - Car is put into off road height mode.
- Graph 70-90secs - Car is put into normal height mode.

As you can see the voltages on one side are going in the opposite direction to the other side. From this video https://www.youtube.com/watch?v=xVOOYA4rp2g - I think the issue are the sensors on the left side of the car - both front and rear left.

Can somebody sanity check the above? Is there anything else I should be doing to diagnose.

Dropbox

Originally Posted by Graeme

Voltage change direction wrt height changes is different for different LR models including different year models, but LR seem to have standardised across later models. Left to right and front to rear won't necessarily be the same voltage change either.

Did you read the suspenison fault codes? Your orange then red after a while is often different stages of insufficient air from the compressor, but the fault codes really should be the starting point for diagnosing causes of suspension system faults.

Yes I did read fault codes - that's how I got to change the rear right sensor which was initially erroring. The error codes following that were generic in nature (cross articulation - intermittent). From what I have read/gathered and also from the diag tool - this type of error is related to height sensor and usually requires calibration after new one is put in.

I suspect I just had to do the calibration as once new sensors come in the system has to re-base to the new values coming in from the new sensor. Done and now all is good.