Grande self-levelling suspension not working?

[Way2go Member Find all posts View Profile Close Way2go]

Found this from Darren:

"If you set them to high, then it will auto low when you try to go to high, and if both sides read different, then it will also go to default low and stay there."

No mention of the auto levelling though.....

And mine definitely isn't sitting on Low.

I've emailed Darren to see if he has any ideas.

[Guest Close Guest]

Have you checked you havent simply bumped the auto level OFF button on the console?

[Way2go Member Find all posts View Profile Close Way2go]

Have you checked you havent simply bumped the auto level OFF button on the console?

There is no button for the auto-levelling that I am aware of.

The only button I have on the console is to turn the height adjustability (low/normal/high) off, not the auto-levelling.

Where is this switch for the auto-levelling?

[1coolbanana Avid PP Poster! Find all posts View Profile Close 1coolbanana]

Just to clarify a few facts about how it works.

Ride control is a totally independant feature and is in no way connected to any other feature.
It is a "dumb" feature which means it is not connected to even the ECU, let alone the height control for the rear.
You can disconnect one or all the connectors at the shocks al the rest of the vehicle is none the wiser.

When you upgrade your suspension on the Grande, the ride control feature is lost by disconnecting the connectors and changing the shocks.
No other feature on the prado knows this or cares or is influenced by it.

The ride height is only controlled at the rear and is also a "dumb" feature, is not closed loop and is not related to the height at the front.
The rear height is controlled by potentiometers that are connected to levers at approximately a 3 to one ratio and the three position are controlled by an output voltage from each potentiometer independently for each side thus being able to compensate not just for height but also uneven height.

That is why the rear height is easy to modify when you install a lift (contrary to most fitters who make this out to be rocket science so they can charge more), all you do is space the brackets that hold the lever arms to whatever height you want.
This is also the easiest and most practical way to do it so if the necessity arises to go back to standard, just take out the spacers. Any other method is dubious and not easily reversable.
The potentiometers are apparently quite fragile when it comes to axial loads ( I have not tested this ) and can be easily damaged, which is another reason to user spacers on the mounts.

When the height (and the potentiometers and voltages move outside of range) the pump is either activated to increase the height or a valve opens to bleed air to lower the height to bring the voltage values back into the acceptable limits.

Those voltages have a tolerance band and this voltage tolerace can manifest itself in slightly different heights on either side.
It can also manifest itself in slightly different heights when loaded and unloaded whilst within that tolerance (usually within 20mm).

These functions only operate when all required conditions are met eg, only when the motor is running, within predetermined limits etc.

Hope thats helps a bit.

[KAKADAZ Avid PP Poster! Find all posts View Profile Close KAKADAZ]

Great post I learnt a few things. ^^^^

[Guest Close Guest]

There is no button for the auto-levelling that I am aware of.

The only button I have on the console is to turn the height adjustability (low/normal/high) off, not the auto-levelling.

Where is this switch for the auto-levelling?

Console..


Maybe start checking fuses and stuff as well... There is some stuff for the height control in the engine bay fuse box.

[Way2go Member Find all posts View Profile Close Way2go]

Console..
[ATTACH=CONFIG]2904[/ATTACH]

Maybe start checking fuses and stuff as well... There is some stuff for the height control in the engine bay fuse box.

That is the switch I knew about - but it only relates to enabling the selection of low/normal/high, not the levelling AFAIK. I tried it anyway, and when I pushed it the 'OFF' light came up under the L/N/H light in the instrument cluster, so it wasn't switched off anyway.

I found 1 fuse in the engine bay for the suspension, and that is OK as well.

[1coolbanana Avid PP Poster! Find all posts View Profile Close 1coolbanana]

Im pretty sure theres more than 1 fuse for the systems.
I think there is two fuses and two breakers, Ill have a look tomorrow.

[waltec Senior Member Find all posts View Profile Close waltec]

That is the switch I knew about - but it only relates to enabling the selection of low/normal/high, not the levelling AFAIK. I tried it anyway, and when I pushed it the 'OFF' light came up under the L/N/H light in the instrument cluster, so it wasn't switched off anyway.

I found 1 fuse in the engine bay for the suspension, and that is OK as well.

All the 1 system, as 1CB posted, the system is just looking at the voltage coming off the 2 sensors on the rear suspenion arms. It just compares the voltage from the sensor and a preset voltage, that preset voltage is determined by the height switch (Low - Normal - High). The off switch is there to turn the system off before jacking the car (ie car hoist) if turned on when body is lifted the system thinks there is too much air in the bags and releases it, when the vehicle is lowered there is no air in the bags, and this could damage the suspension.

Matt

[Way2go Member Find all posts View Profile Close Way2go]

Noted today that the 'Off' switch for the suspension height control cannot be 'accidentally' hit and have the system shut down, as if you do turn it off it automatically re-engages once the vehicle goes over 30km/h.

Still haven't sorted out why the levelling doesn't work when the height control does (and both adjusters are at the same height). Also there is a difference of 20mm in the ride height between left and right.

I've given up and have booked it into Mannells on Thursday - they say they've lifted 'countless' 120 Grandes (hence why they were prepared to give the Kakadu a go) so hopefully they can sort out what is (or isn't) going on.........

[Troy1 Member Find all posts View Profile Close Troy1]

Thankyou very much for this info, as i was thinking of doing aftermarket to the grande :-) i still have all the other grande suspension mod threads to read yet but

[Callo Junior Member Find all posts View Profile Close Callo]

I have the opposite problem. My 2003 Grande maintains constant height but will not adjust height. I will check the fuses when 1coolbanana reports on where and how many fuses are involved. If that is not the problem I have been told it could be the computer taht controls it. Hope it is a fuse problem.

[1coolbanana Avid PP Poster! Find all posts View Profile Close 1coolbanana]

As far as fuse and relay location, its all in the handbook mate.
The ECU has no influence or control on height, the system operation is independent.

[Way2go Member Find all posts View Profile Close Way2go]

Mannell's couldn't find any reason why the levelling isn't working when the L/N/H adjustment still functions fine.

Had to leave for this long trip without it functioning, so they upped the N setting by 10mm or so to compensate slightly for the extra load I'm carrying.

Not sure where to when I get home in terms of getting it sorted though...... (Toyota will take one look at the TEMS shocks not being there and start proposing all sorts of reasons why their computer won't be able to resolve it - despite TEMS having nothing to do with the self-levelling).

[Way2go Member Find all posts View Profile Close Way2go]

Fuses look OK, so maybe a relay issue? Not sure how to tell if a relay is working our not..... That said, I have found a workaround - once the camper is attached and the back loaded up, I can push the Lo/N/Hi button to start raising the rear then press it again to set it back to normal height, and this process gets the system to recognise the correct voltage for the N height. I'd prefer the system to pick up the drop in the rear automatically as it is supposed to do, but at least this way I can get the vehicle sitting level under load.