First off I would like to sincerely thank all of those that have come before me providing excellent content for the all of the owners out there in the world to read and assist with problems. I purchased a 2004 LX470 during covid in 2021 and it has taken me two years to identify my AHC and VSC problem, our first born was in that timeline so forgive the duration.
State of the vehicle upon receipt: Pressures were outside of normal, AHC in normal was fine, but did take a long time to get into high.
Our LX470 came with the ARB front bumper installed, so extra armor weight up front meant verifying the pressures first. Let's just say that was a challenge of it's own, but I did crank on the torsion bars and pretty much bottomed them out. Since the suspension was in such bad shape, I did try taking it to the Toyota dealership to have some general maintenance done and to take a look at it. They wanted to replace all 4 shocks because they were not responding somewhere in the neighborhood of $7k. So I first wanted to refresh all of the globes and ordered a set from Japan. I replaced the fluid and globes all at once and there was virtually no change.
State of the vehicle at this point in time: Pressures were in normal condition, AHC height control fully functional
When I finally had more time to do research and look at wiring diagrams, I did find a couple mentions of the AHC/VSC switch that caused some issues. I had also found reasons to look into the actuators and the height sensors. I started with actuators and part way through I decided to pull the switch and visually inspect. I didn't find any obvious shorts, but the VSC dial electrical pads were quite worn and the metal fingers for the dial needed to be bent out to ensure contact. Upon reinstallation there was no change. So I decided to dig deeper and try to trace the switch with a multimeter. Ultimately I decided to attempt driving the vehicle with the switch disconnected. Eureka - the system was finally responding and adjusting the actuators. The system went completely from not doing the job intended to functioning properly. The steering tightened up significantly, the vehicle over bumps was much less floppy, and the vehicle was much more flat in the turns.
I just ordered a replacement switch part number (89299-60020) from an online Toyota parts dealership. I will update when the new switch is installed. I hope this post helps someone else seeing a complete failure without any indication of failure.
I do suspect that the absorber/shock bushings need replaced to further improve things.
Additional items purchased that will be installed to completely freshen up all of the underside:
State of the vehicle upon receipt: Pressures were outside of normal, AHC in normal was fine, but did take a long time to get into high.
Our LX470 came with the ARB front bumper installed, so extra armor weight up front meant verifying the pressures first. Let's just say that was a challenge of it's own, but I did crank on the torsion bars and pretty much bottomed them out. Since the suspension was in such bad shape, I did try taking it to the Toyota dealership to have some general maintenance done and to take a look at it. They wanted to replace all 4 shocks because they were not responding somewhere in the neighborhood of $7k. So I first wanted to refresh all of the globes and ordered a set from Japan. I replaced the fluid and globes all at once and there was virtually no change.
State of the vehicle at this point in time: Pressures were in normal condition, AHC height control fully functional
When I finally had more time to do research and look at wiring diagrams, I did find a couple mentions of the AHC/VSC switch that caused some issues. I had also found reasons to look into the actuators and the height sensors. I started with actuators and part way through I decided to pull the switch and visually inspect. I didn't find any obvious shorts, but the VSC dial electrical pads were quite worn and the metal fingers for the dial needed to be bent out to ensure contact. Upon reinstallation there was no change. So I decided to dig deeper and try to trace the switch with a multimeter. Ultimately I decided to attempt driving the vehicle with the switch disconnected. Eureka - the system was finally responding and adjusting the actuators. The system went completely from not doing the job intended to functioning properly. The steering tightened up significantly, the vehicle over bumps was much less floppy, and the vehicle was much more flat in the turns.
I just ordered a replacement switch part number (89299-60020) from an online Toyota parts dealership. I will update when the new switch is installed. I hope this post helps someone else seeing a complete failure without any indication of failure.
I do suspect that the absorber/shock bushings need replaced to further improve things.
Additional items purchased that will be installed to completely freshen up all of the underside:
- U-joints
- 555 tie rod ends
- 555 upper and lower ball joints
- Super Pro bushings for everything (long list)
