Suspension height P38

Hiya,

Ive not had my Range Rover long but ive just notice the the n/s/f suspension seems a little low comapred to the rest of the wheels. On the normal setting its about 5cm lower than the o/s/f and remains about 5cm lower through the height range. The system is all working OK and pumps up and down just as it should. I have recently replaced the front airbags as they were perished.

The heights should be.....measured from the wheel CENTRE to the wheel arch;

Standard height 790mm +/- 7mm
High 830mm +/- 7mm
Access 730mm +/- 7mm
Low Profile* 770mm +/- 7mm
Extended* 850mm +17/-7mm

**These settings are ECU controlled**:behindsofa::tea::smokin:

Hi,

Was the suspension level before you changed the airbags? I recently changed all 4 airbags and now my P38 is a bit higher on the nsf (only a few mm though) - 5cm is a BIG difference. The independent LR garage suggested the suspension may need recalibrating after having new airbags fitted. So far I haven't bothered because in my case the difference is pretty small. I don't understand why changing the airbags would require a recalibration though.

mikeateves

Ive just taken it round the block and run it through the different heights again and there is still a difference but only about 2-3cm now. I guess the height sensors may need calibrating if thats possible?

Yes, they probably do. Check the heights on firm level ground. You can do what others have done on here and buy the lead off Egay and get the free software and do it yourself or there may be an independant who may be able to sort you out at a much lower price than a stealer.
Sometimes the heights can be calibrated in 10minutes, another time it can take ages trying to get the last couple of millimetres

Very possible that the height sensors are worn out.The resistive track inside will give the same output at more than one angle,so when the ecu compares the output voltages from each sensor to check its level it does not really know where it is.Eventually it will fault,often giving a "cannot raise" or "cannot lower" a particular corner as the ecu commands a valve to open,which it does,the car goes up or down at that corner but ends up with the same reading or even less/more output voltage than the target it was looking for.
Changing the airsprings will make no difference to rideheight as the ecu will just adjust it to its target settings.
Any height sensors that have done more than 80-100K miles are likely to be worn.
With the ignition off,pull out the EAS delay relay,(Big black one under the LH front seat.) then disconnect the link arm off each sensor.Unplug the loom from the sensor and connect a multimeter set to Ohms between the centre term and either of the outside ones.Gradually move the arm through its entire arc and watch the multimeter reading.Look for a very smooth transition of resistance,if its not,or there are several spots with the same reading its shot.Same if it reads open circuit anywhere.Sorry to dribble on,but I see lots of these cars after lots has been spent not fixing them,and very unhappy owners.

Lot of sense in what 8inav is saying. A potentiometer is basically an arm moving accross a coil of fine wire. Obviously if the arm is constantly moving accross a small area all the time, it wil wear the wire down and the unused portion of the track will get dirty.

Irishrover said:

Lot of sense in what 8inav is saying. A potentiometer is basically an arm moving accross a coil of fine wire. Obviously if the arm is constantly moving accross a small area all the time, it wil wear the wire down and the unused portion of the track will get dirty.

Click to expand...

maybe they were back in the days when it took 5 minutes for your radio to warm up - these days they are carbon or other resistive coating film tracked

Irishrover ,
couple of questions about the ride heights you posted above, i just measured mine to get a baseline to check against when i fit my new arnott airbags and my measurements seem way off yours. Mine vary a bit from corner to corner but averageing them out my heights are (measured from wheel centre to wheel arch) high = 510 standard=470 low=430 access=410.
The difference between heights is similar to yours about 40mm between settings , but mine seems to be a lot lower on average.
was just wondering where you got your readings, from did you measure yours or get them from some documentation? I have a p38 hse 4.6 on standard wheels and tyres, any ideas as to what might be causing this difference, dont want to wreck my suspension trying to match your measurements if there is some reason mine are so different.

I think those measurements are from the floor not the wheel centre

If you took it to the main dealer they would use a set of blocks that fit betwixt axle and chassis to set up a datum. Have a quick search for Storey Wilson and his free EAS unlock sotware. You will need a laptop and a lead. As Eight says there is a good chance that one or more of the
sensors are fubared, so its good advice to check these before messsing with any settings. To save you looking, here is a clicky to his site