rstl99

I am looking at a couple of used GX470's and am not familiar with the sophisticated suspension and ride components on these cars (my past SUV's were more "basic" i.e. 60 and 80 series LC's). Namely the:
Downhill Assist Control (DAC)
Hill-Start Assist Control (HAC)
Rear Adjustable Height Control (AHC)
Optional Kinetic Dynamic Suspension System (KDSS)

Although I don't plan on taking a GX470 on extreme off-roading expeditions, I do travel remote country roads and hilly terrain so would need to know I can rely on those components if-when I should need them.

1. how reliable are these in a 10+ year old GX470 with 120-150,000 miles on it?
2. how difficult or expensive to repair if something goes wrong?
3. how to check whether they are all working right, when looking over and test driving one?

Thanks.

180ls1

The 4wd system is incredibly reliable. These cars are full time AWD, so switching them into more serious 4wd modes changes very little. I bought mine because it is probably the most reliable 4wd on the market. Any of those features you mentioned could fail and you would still be able to drive home.

rstl99

Thanks 180, that sounds like a reasonable viewpoint. I suppose there's never any sure thing when buying a 10 year old vehicle with some mileage on it (especially one without any service records like the one I've been looking at a local used car lot), but one probably has better odds with a Lexus than almost any other brand, unless it's been seriously abused or neglected.

chiph9

DAC - very few people actually use it, as once you're in low gear and low-range, the ratios are such that it just isn't required.

HAC - My 2004 doesn't have this.

AHC - very useful when hooking your boat to the hitch. Lower the suspension, move the trailer on top of the ball, then raise it back up. Then crank the trailer wheel up after the weight is off it.

KDSS - My 2004 doesn't have this. But what it does is disconnect the sway bar so that the wheels on each side have more articulation. Could be useful in rare cases offroad.

The KDSS is reliable, but expensive to repair when it breaks. The air suspension is reliable, but expensive to repair when one of the airbags starts leaking. Most people replace it with a conventional suspension when this happens.

Failure indications: The DAC uses the ABS pump, so if you see a brake light on the dash (that isn't from the handbrake being set) you'll know there's a problem with the braking system (and thus the DAC)

The air suspension will be resting on the bump stops, and changing the height setting will have no effect. There is an air pump for this, and you should hear it run when going from low to high ride height. Going from high to low you'll hear the air vent out (not the pump).

KDSS or HAC failure indications - no idea.

One thing to look for is a leak from the transfer case. Crawl under the vehicle and look for seepage on it.

The rest of the GX is pure Land Cruiser, which is one of the best 4x4's on the planet. Dirt roads will not be a challenge. Hilly terrain will come down to having good knobby tires.

Chip H.

180ls1

Yeah. I would concern myself with condition and maintenance more than age or miles. For example my 03 with 140k was a one owner car when I purchased it. If you looked underneath there is not one leak, torn boot, or anything to make me suspicious. It looks better then domestics with half the miles and that hurts me to say lol because I love domestics and all my previous vehicles have been domestic. This Lexus is just sooooo much better put together.

rstl99

Thanks Chip for the very useful perspective on those features, that's very helpful for me.
Indeed, I'll be looking carefully for any fluid leaks on whatever truck I decide to purchase. Unlike the old Land Rovers I used to own, I wouldn't expect much on Land Cruisers or Lexus's! :-)

chitown40

KDSS has its own idiot light on the dash when there is a problem. You can pull the code for KDSS just the same as any OBD-II code.