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Looking for some advice...2005 LX470 with 200,000 miles.
2017: AHC began flashing "off" while in neutral position. Unable to raise or lower. AHC fluid level unchanged. Code scanned as left front height sensor.
There wasn't a noticeable issue with the ride, so didn't bother fixing; just chalked it up to a luxury I didn't need.
Last week, the rear end dropped noticeably, and began to ride very rough, almost as though no shock absorption at all.
Took it to a Toyota dealer (no Lexus dealer nearby), scanned the codes and came back with "left front height sensor"...$875.
(No, I won't be paying that, I would DIY)
My fear is that they scanned the code and gave me the diagnosis ($185) without actually looking at the vehicle.
I asked if the front sensor could cause the rear to drop suddenly after over a year, and he said, "the whole system is connected so could be".
My own research is showing the accumulators or globes can also be an issue, and I don't want to replace the sensor only to find out that the globes are the major issue.
Questions:
1. Would the front sensor cause the rear to drop?
2. How do I know if the globes/accumulators are an issue or not?
How long (mileage and time) has it been since the last ACH fluid change?
Not sure if a front sensor can cause a change in the rear.
If you'd like to check general function, you should see at least 8 small graduation on the side of the reservoir, minimum, when you go from high to low or low to high.
Send a PM to user PADDO here. He is THE acknowledged expert on AHC both here and on ih8mud.com
200,000 miles and 14 years, never had the fluid changed. The fluid appears to be "full", but no change in level (or noise, or movement) when attempting to raise or lower height of vehicle.
However, that's been the same for 2 years. The rear dropped last week..
That's my fear, too. I'm going to replace the height sensor just to get that code out of the way, and see where it takes me from there.
Thanks for the help, hankinid!
That's my fear, too. I'm going to replace the height sensor just to get that code out of the way, and see where it takes me from there.
Thanks for the help, hankinid!
You are welcome.
Are you going to fix the AHC, or just convert to Land Cruiser torsion bars and rear springs?
I'm not sure. Kind of got hit with this out of the blue, so haven't had a chance to research. Cost is more important than luxury at this point, since it's an extra vehicle that the kids use. Definitely something to consider.
UPDATE:
Toyota mechanic wasn't able to diagnose beyond the front height sensor, and for $900 I wasn't willing to gamble.
Replaced it myself and the flashing "off" on the AHC is gone. Front end raises and lowers using the height adjustment, which was not working previously.
However, the back end still sits low, and ride is very bumpy/rigid.
Overall, it's 50% better, but still not acceptable.
Next step, I'll clean/replace the rear height sensor...fingers crossed!
Side note, Toyota spent a few hours (at my request) to see if they saw anything obvious with the suspension beyond just reading the code. Seems like that would be something they would do without my asking, but sign of the times. A flashlight, and 10 seconds later, I see the sway bar connection is shot. No mention of this on the "Multipoint Inspection", even though it sits 6" below my missing front height sensor. I'm beginning to lose my faith in dealer mechanics :-/
No excuse for a dealer's shop missing lower sway bar brackets...not an uncommon failure, but something that's very easy to check. New brackets and bushings are not a lot of money, and an easy diy job.
Your area may be different, but that's why I picked a local specialty Lexus/Toyota shop v. dealers...warranties are up on both the LX and Land Cruiser. You may want to register at ih8mud.com and see if you have a good indy shop in your neighborhood.
Since I've replaced the front height sensor, the AHC now adjusts from low to high in both front and rear.
The ride is actually bearable in H (as opposed to the bull riding that occurs in N/L)
However, once I get driving and it drops to N, the front lowers about 1.5" and the rear drops 5".
Setting it in L drops the front another 3 inches, but the rear doesn't change.
What would cause the rear to only maintain H/L? My guess is that the rear height sensor might be the cause, does that sound right?
FYI I bought a techstream off ebay to check the pressures, just having some installation issues. Once I get that resolved, I'm hoping to get some objective answers.
The AHC system on the 100 series is complex and problematic and you'll find few folks, even at a Lexus shop, that understand the system.
If you really are going to dig into it, you should be fully immersed here: https://forum.ih8mud.com/threads/def...604577/page-31
- There are a couple of guys on there that probably know more than the Toyota engineers at this point.
And for what it's worth, a full fluid flush isn't a bad place to start, along with a fluid height test to baseline things, then globes, then sensor settings, then neutral pressures, etc. Lots of variables, and attacking one without a good baseline and testing everything else is just a merry-go-round.
It does help if your sway bar connection isn't broken. ;-)
06-25-19, 12:47 PM
AHC / Suspension Problem
