Hi all! I am brand new here, first post.
2004 Toyota Land Cruiser Turbo Diesel
We are in Nicaragua and I found some good information of how to go through the system and debug the issues, but we are currently stuck in the middle of the jungle and the ride height is set to LOW and won't go back up.
Are there any hacks for fully disabling the entire system or locking it in HIGH? We can't make it out of here in LOW. We don't have a tester and minimal options for debugging and fixing.
Any ideas or hacks for just getting back to civilization?
The previous replies in this thread answer the question as best possible. Here are some pics which may help.
First, consider weight issues as previously described in this thread, by weight removal if possible, or, by torsion bar adjustment.
Torsion Bar Adjusters -- one on both sides of chassis, about half-way between front and rear wheels:
Turn the adjuster clockwise (looking up from below) -- multiple turns to shift weight off AHC system and onto torsion bars. The weight transfer of one full turn on both adjusters causes a reduction in Front AHC pressure of ~0.2Mpa, so try 5 full turns on both sides to make a real difference. Do this with engine OFF, make hub-to-fender heights both sides as equal as possible. This will be hard with vehicle at "LO" -- can try jacking vehicle to get weight off the suspension to make it a little easier while doing this
BUT BE VERY CAREFUL -- you still will have to wrench hard, do not want vehicle coming off the jack on top of you!! Or see if you can start AHC pump to get vehicle to raise by (1) direct connection to the battery by suitable leads if you are carrying them, or (2) by using "Active Test" with a paperclip or similar as a connector per Section 5 at Page 6 of the attachment -- the latter method will not work if there are other faults.
You
might succeed in getting the vehicle to "HI" height -- but the system is designed to drop the vehicle back to "N" height when the vehicle speed exceeds 30 kilometres per hour (19 miles per hour). Some Owners have devised circuit changes which cause "HI" height to be held but that is not a job to do on the trail -- and some Owners would say that this is not a good idea anyway.
So the aim is to re-establish "N" height as best possible.
Note that, unlike a conventional suspension, on an AHC-equipped vehicle the torsion bar adjusters are not used to vary the ride height of the vehicle. Ride height is adjusted at "N" by the Height Control Sensor adjusters. The Suspension ECU then determines "LO" height and "HI" height.
Second, if weight is not the issue, consider damage or internal failure of sensors or linkages or wiring harness or connectors in the Height Control Sensor circuits as previously described in this thread.
The idea of disconnecting Height Control Sensors is to try to induce faults ('fail safe function' for Height Control Sensors) which, theoretically, should cause the vehicle to adopt "N" height -- unless there are other faults disallowing AHC Pump operation or unless the vehicle is too heavy to raise.
Front Height Control Sensors:
Found in the Left and Right wheel arch as shown below. Follow harness rising to engine bay -- there is a connector there which can be pulled if it is difficult to pull the connector behind the sensor bracket in the wheel arch. Be sure that the correct three-wire harness has been followed. The harness connector sits in the engine bay above the wheel arch on each side of the vehicle, next to a two-wire connector and circuit which goes to the wheel speed sensor.
Rear Height Control Sensor -- there is only one, forward of Rear diff, attached to chassis cross-member and to LHS Rear Upper Control Arm:
Rear Sensor connector can be seen. It is easier to get at with the spare wheel out of the way.
