In this brief article we are going to discuss the different Toyota Land Cruiser KDSS suspension issues, what the causes are, and how these issues can be effectively dealt with.
Top 3 Toyota Land Cruiser KDSS Suspension Issues
- KDSS Lean after suspension modification
- KDSS warning lights ON
- Front-end clunk Noise
What does the Toyota Land Cruiser KDSS Suspension do?
KDSS is the abbreviation for Toyota Land Cruiser’s “Kinetic Dynamic Suspension System”. It is Toyota’s brand name for its unique and intuitive Anti-roll Bar (ARB) Control System.
KDSS consists of one hydraulic actuator cylinder each for the front and rear ARB’s. The upper chambers of both these front and rear actuators are inter-connected through one hydraulic line. While both of the lower chambers of the actuators are similarly connected.
Each of the hydraulic lines has an electronically controlled accumulator valve.The actuators act between the ARB and the chassis. When cornering, the vehicle senses the dropping of the wheels on the inner side and signals the accumulator valves to apply hydraulic pressure in such a way as to increase the Roll-resistance of the suspension.
In articulation and uneven roads, in other vehicle suspension systems, the ARB functions mechanically interpreting road undulations for cornering Roll. So it resists the wheel articulations, unwantedly, leading to body roll. It is an uncomfortable experience for occupants who will feel an additional effect of roll over undulations.
But in the KDSS, for rough roads, it senses when the vehicle goes over uneven roads and removes pressure from the actuators, allowing the actuators to freely move up and down, thus diminishing the ARB’s effect in situations where it is not required to resist roll.
In an Articulation situation, the KDSS applies pressure to maximize ARB movement and allow all 4 wheels to contact the ground.
When did Land Cruiser get KDSS?
The Kinetic Dynamic Suspension System was introduced first as an option on the 2004 model year in the Lexus GX 470 in North America. The KDSS was also introduced as an option on the 2008 model year Toyota Land Cruiser.
Which models of Toyota came with KDSS?
2010–2016 Toyota 4Runner Trail Edition
2017–present Toyota 4Runner TRD Off-Road
2008–present Toyota Land Cruiser
2004–present Lexus GX
2010–present Toyota Prado
What are the Toyota Land Cruiser KDSS Suspension problems?
KDSS Lean after fitting a modified suspension
If you fit an aftermarket suspension ‘Lift-kit’ to raise the suspension height of your KDSS Land cruiser, it sometimes develops a lean to one side or corner.
KDSS warning message turning on
Front-end clunk noise
What causes KDSS Suspension Problems?
KDSS warning light coming ON:
- If all warning lights including ABS come on, then it could be a wiring issue. Try replacing the Driver-side and passenger-side ABS wiring
- The external housing is designed for easy ventilation. It therefore also allows mud, salt and any other road debris to accumulate in the housing. This results in corrosion and then causes a Leakage in the stabilizer control housing assembly.
- If the controller was not the issue, and you hear ‘Clunking’ noises from the suspension then it could be a case of low system pressure.
How to Deal With KDSS Suspension System Failure?
KDSS warning light coming ON:
- Apart from cleaning the underbody, you need to also periodically flush out the housing to prevent mud and or salt from packing accumulating in the area around the control assembly.
- If you observed ‘clunking’ noises from the suspension, then you need to get the KDSS system tested for pressure. It should be closer to 3MPa. Any drop from that pressure means that it allows the ARB to move resulting in clunking noise as well. If you find that the pressure was well below 3 Mpa, then the pressure needs to be corrected.
How do I reset my KDSS to solve the suspension Lean Problem?
- Measure and record the distance from the ground to the bottom of the fender on each side of the vehicle
- Locate the KDSS control-valve box (approximately between the muffler and the chassis), attached to the chassis rail.
- Loosen the two shutter valves a maximum of 3 turns, using a 5mm allen key.
Loosening the valves more than three turns, could allow air into the KDSS hydraulic system, which would require a bleeding procedure to be executed by an expert)
- Park the vehicle on a level, hard pavement
- Place a 75mm-high, 1 foot long, wooden plank either in front of or behind the LEFT REAR tire.
- Slowly and carefully Drive so that the tire is up on the wood.
- Instead of driving onto the plank, you could also use a jack to raise the LEFT REAR AXLE HOUSING until the tyre has a gap of 50mm from the ground. (The 25mm difference with this method is to allow for the flex in the tyre).
Re-tighten the two shutter valves at the KDSS valve box using the same 5mm allen key head used in Step 2.
- Drive the vehicle back down from the plank
- Repeat the fender height measurements on each side.
- If the measurements of the left and right sides are within 10mm, it means that the problem is fixed.
- If the leaning problem still persists, you can repeat the procedure, this time increasing the height of the plank that you drive onto (eg: from 75mm to 100mm or 125mm), or,
By jacking up the axle higher.
In this brief article we have discussed the different Toyota Land Cruiser KDSS suspension issues, what the causes are, and how these issues can be effectively dealt with.
Frequently Asked Questions (FAQs):
Is KDSS Suspension good?
Yes, the KDSS suspension is quite a clever and intuitive system that provides the right balance between ‘Ride Comfort’ and ‘Handling’. The system is built in such a way as to react and change the suspension roll stiffness to either
- ‘Zero to Low’, when on a Rough patch or articulation
- ‘High’ when in a cornering situation
Is KDSS worth it in Prado?
The Kakadu Horizon top-of-the-line variant comes with Toyota’s Kinetic Dynamic Suspension System (KDSS) over and above the Kakadu variant.
Other Add-ons in the Kakadu Horizon are
- 7 seats (front seats are leather-accented, heated and ventilated, powered third-row folding seats)
- Electrically adjustable steering column
- 130kW/450Nm 2.8-litre turbo-diesel engine and six-speed automatic transmission
- dual-range 4WD
- driver-assist systems, such as crawl control and multi-terrain select (both for off-roading),
- adaptive variable suspension
- rear air suspension
- 18-inch alloy wheels
- 3-zone climate control air conditioning,
- Panoramic-view monitor
- Toyota Safety Sense (including Pre-Collision Safety System with Pedestrian Detection, High Speed Active Cruise Control, and more)
- JBL audio system, a rear-seat entertainment system (DVD player) with 9.0-inch screen and three wireless headphones, as well as two rear USB chargers
All these extras cost around $5000 extra. It is definitely worth it for the price.