OUTLINE
The air suspension system uses pneumatic cylinders instead of the coil springs that are used in a conventional suspension. The suspension control ECU analyzes information based on the input signals from the height control switches, height control sensors, and various ECUs, and operates the height control compressor assembly, and height control solenoid valves to control the vehicle height.
Using the 4 height control sensors, the suspension control ECU detects changes in the vehicle height resulting from the number of occupants or the amount of cargo. Then, the suspension control ECU controls the height control valves and the height control compressor assembly in order to automatically adjust the vehicle height to maintain a constant vehicle height. Thus, a high level of ride comfort and handling stability are achieved.
While driving, 3 vehicle height mode settings can be selected by operating the height control switch: HI (high), N (normal), and LO (low) mode:
The HI (high) mode vehicle height ensures the vehicle's ability to traverse rough roads.
The N (normal) mode vehicle height helps realize excellent controllability and ride comfort during normal driving.
The LO (low) mode vehicle height improves aerodynamics and reduces roll angle.
To enhance convenience when loading and unloading with the vehicle stopped, luggage mode is used to lower the vehicle height 30 mm compared to the normal vehicle height. In accordance with the adoption of this mode, an additional height control switch is provided in the luggage compartment to supplement the height control switch located at the driver's seat. Providing this height control switch in the luggage compartment allows the user to select luggage mode even while the engine switch is off.
| Selected Height Mode | Adjustment Value |
|---|---|
| HI (high) Mode | + 30 mm (1.2 in.) |
| N (normal) Mode* | 0 mm |
| LO (low) Mode | Front: - 20 mm (0.8 in.) Rear: - 5 mm (0.2 in.) |
| Luggage Mode | - 30 mm (1.2 in.) |
*: The adjustment values shown in the table represent deviations from the 180 mm (7.0 in.) ground clearance in N (normal) mode.
PRECAUTION
Precautions during normal use
To switch modes using a height control switch, it is necessary to press the switch for at least 1 second.
Before using a height control switch to lower the vehicle height, confirm that the vehicle body will not make contact the ground.
Use caution when driving in HI (high) mode since the vehicle center of gravity is raised.
Do not select HI (high) mode while driving with luggage on the roof rack.
If the vehicle is started off in luggage mode, the vehicle height will automatically return to N (normal) mode when the vehicle speed reaches 8 km/h (5.0 mph). Pay attention to height restrictions while driving.
Do not select LO (low) mode when driving on rough roads. In addition, pay attention when starting the vehicle off in luggage mode on rough roads as the vehicle body may contact the ground while the vehicle height is returning to normal.
Before raising or jacking up the vehicle, be sure to disable vehicle height control using the height control OFF switch.
If the vehicle speed reaches 30 km/h (19 mph) while vehicle height control is disabled, the auto-leveling function will automatically resume.
After the engine has stopped, the vehicle height lowering control will continue for a maximum of 60 seconds.
The vehicle height may lower due to changes in temperature or being parked for an extended period.
To protect the height control compressor assembly, the vehicle height cannot be increased repeatedly. If the control compressor assembly operates continuously for longer than 100 seconds, it will stop for a certain period of time then resume. In such instances, vehicle height control mode selection may be cancelled.
If the vehicle height is lowered repeatedly, the pneumatic tank assembly, which temporarily stores exhaust air, may fill to capacity, decreasing the lowering speed.
Before attaching or detaching a trailer, camper or other towable object, press the height control OFF switch and stop the engine to disable vehicle height control.
Height control compressor assembly operation noise can be heard when the vehicle height changes due to a height control switch operation, passengers getting in or out, cargo being loaded or unloaded, or normal vehicle height being restored from luggage mode. This noise does not indicate a malfunction.
The vehicle height mode cannot be changed in situations where the vehicle is driven over a large curb or on a rough road where the suspension is at full extension.
Precautions when removing and reinstalling a related component
If the height control valve sub-assembly and pneumatic cylinder assemblies have been replaced and the vehicle height is lowered, be sure to perform the following procedure in order to protect the height control compressor assembly: Start the engine and wait for 1 minute. Stop then restart the engine to restore the vehicle height.
If lowering the vehicle with the pneumatic cylinders discharged after the height control valve sub-assembly and pneumatic cylinder assemblies have been replaced, be sure to connect the tube to close the air path. If the vehicle is lowered with the air path open, the joint of the diaphragm on the air piston side may become loose, adversely affecting durability.
Do not apply torsional torque to the diaphragm while the front pneumatic cylinder assembly is discharged. Doing this may cause the diaphragm to be twisted, adversely affecting durability. To connect the tube to the front pneumatic cylinder assembly, one person should hold the chamber steady while another person is tightening the tube.