'03 LX 470 AHC issue...but not really? (1 Viewer)

[Amoun]

Good morning everyone,

Originally posted this on 200-series, was advised that I might get better help here:

Was scouring the web until I found this forum and was really hoping to get a few opinions.
From the title: I have an 03 LX470 and 0 issues with the car 'till now. AHC seems to be acting up but I did not find similar issues on other posts. I have read about issues with sensors, etc.

The problem:
The rear of the car was sitting unusually low and the ride was very, very bouncy (the back, at least). I played around with the height control and the truck does rise, the fluid levels seem to be fine and it does lower. However, when it goes into Neutral, the front is at the right height but the back drops to low.
This was not happening all the time and the "work around" I have found was when the truck raises it self back up to the appropriate height I would catch it half-way and turn "off" the AHC, forcing it to be "paused" in neutral. It would then ride perfectly fine with 0 bounce and 0 issues.

Few days ago, it took it self out of the "Off" setting and proceeded to lower the rear again.
Yesterday, the rear went back into low setting and does not raise at all now. The ride continues to be bouncy.
I will absolutely be taking it to a mechanic and I hope maybe its just contacts or just a wonky/dirty sensor as this does not seem to be consistent and I am not getting any lights for the AHC but it's definitely a little strange.

Anyone seen/heard anything similar?

 

[tacoduck]

check you ahc fluid. does it look bad? A good place to start would be to swap the old fluid with new.

 

[Knowbuddy]

You have a bad rear sensor is my guess. You should contact cruiser outfitters. They have boxes of old parts that they will sell you on the cheap and that will allow you to trouble shoot before doing anything drastic.

 

[Amoun]

Thank you very much for the quick replies guys

check you ahc fluid. does it look bad? A good place to start would be to swap the old fluid with new.

The fluid is slightly dark-ish so you are right I will get that replaced. But wondering if that would cause the issues? Something clogged? Hmm

You have a bad rear sensor is my guess. You should contact cruiser outfitters. They have boxes of old parts that they will sell you on the cheap and that will allow you to trouble shoot before doing anything drastic.

Thank you very much for this recommendation. I started considering a few options as I heard some repairs can be *very* expensive to the point where people just recommend converting to normal suspension.

Will do both, new fluid and if that does not work, then a new sensors which hopefully should fix the system.

 

[CanadianRockyCruiser]

You should get techstream and check the pressures of each accumulator. It is difficult to diagnose without techstream.

If there is too much weight on the rear, they may be out of specification and adjustments to your torsion bars may be required, or replacement of the accumulators. If the pressures are in spec, checking the rear sensor is a good starting point (as Knowbuddy has suggested).

 

[PADDO]

@Amoun In all likelihood your rear sensor has failed, if you can get a cheap takeoff then by all means swap it out noting that old parts may not necessarily be 100% serviceable. You can however check their internal resistance easily before installing, for that matter you can/should check the one that’s currently fitted and also ensure the linkage is serviceable. Rock auto has the best price for new Aisin sensors if needed, half Toyota/Lexus msrp.
Fluid changeouts are a good thing for most people most of the time but if you’ve got a failed sensor and can’t fully cycle between heights then that’ll affect your ability to properly exchange the fluid. I’d recommend getting it cycling between L and H and then do a fluid change as part of the systems periodic maintenance plan. You do need Techstream or an icarsoft tyt II to facilitate maintenance and repair, unfortunately most failed/worn out sensor issues don’t actually throw a fault code but you can still read the value that they are providing to the ECU and that’s very helpful. And your turning it off trick will only work at speed <50mph then the system turns itself back on. Hope this helps.

 

[Amoun]

@Amoun And your turning it off trick will only work at speed <50mph then the system turns itself back on. Hope this helps.

So that's what it was.
When I think back, it would indeed turn back on after highway driving (did not put the two together before) thank you for that clarification.

It looks like I may need to take it to the mechanic after all (have a trusted one) to see if it is the sensor...which I suspect (and hope) it is as the rear stopped going into H this morning.

Thanks again everyone. Hopefully should be able to post updates if this helps anyone.

P.S. If anyone also has a trusted Toyota/Lexus mechanic in Toronto area, would really appreciate it as mine (although good) does not specialize.

 

[PADDO]

P.S. If anyone also has a trusted Toyota/Lexus mechanic in Toronto area, would really appreciate it as mine (although good) does not specialize.

The overwhelming anecdotal evidence here is that Toyota/Lexus mechanics and dealerships don’t specialize in the AHC/AVS systems either

 

[white_lx]

Have you checked the sensor linkages? Had some totally freeze from the road salt recently (different Lexus vehicle, but very similar). As a result the attachment point fatigued and broke off. A broken sensor linkage might not result in an AHC error code, as the computer thinks everything is fine.

P.S. If anyone also has a trusted Toyota/Lexus mechanic in Toronto area, would really appreciate it as mine (although good) does not specialize.

You can try T-Lex in Markham. They work on Lexus/Toyota, but I'm not sure about AHC.

PM me if you need help with Techstream.

 

[Amoun]

Hi guys
Delayed but a quick update:
It was a rear sensor after all. Took sometime to get the part but its been installed and the ride is like nothing ever happened and AHC works perfectly.

Thank you for your suggestions

 

[68W65D]

Is there any preventative maintenance recommended on the AHC height sensors?

 

[fro20fow]

Anyone seen/heard anything similar?

Not uncommon. Most likely the sensor especially if you have any sort of rust. It seems that the sensors are built to last and generally don't have issues but rust can cause all sorts of issues.

 

[PADDO]

Hi guys
Delayed but a quick update:
It was a rear sensor after all. Took sometime to get the part but its been installed and the ride is like nothing ever happened and AHC works perfectly.

Thank you for your suggestions

and thanks for taking the time to close this out. It’s nearly always a worn out sensor or it’s mechanism.....

 

[twocircles]

You have a bad rear sensor is my guess. You should contact cruiser outfitters. They have boxes of old parts that they will sell you on the cheap and that will allow you to trouble shoot before doing anything drastic.

I believe Cruiser Outfitters sold all of their used parts inventory to another business. It would be nice to know who that might be.

 

[cruiseroutfit]

I believe Cruiser Outfitters sold all of their used parts inventory to another business. It would be nice to know who that might be.

We sold ~100 vehicles worth of used parts to Specter Off-road, but that was in 2001

We've collected a but since that time.