New owner 06 lx470

[BOB F]

Hi,

Just replaced my beloved 98 LC with a 06 470. 64k miles. Bought sight unseen knowing that AHC didn't work. Ugh

Took delivery tonight. It's on the low position, off light always on , doesn't respond when switching it.

Car has an outstanding airbag recall and Lexus will do complete inspection and probably a 10k$ estimate!

What do you think the issue could be and the fix? I am pretty handy and don't mind getting into the fix but I need to get educated. I thought I'd take it to Lexus first to see what they say.

Any comments suggestions are appreciated.

 

[khoaiii]

i recently changed the rear height sensor ($400 part) because it's going crazy. sitting on low or high (rear) when i turn on the car. 64K miles and AHC issue already? it's practically new.

 

[jumptrader]

The airbag recall should be free.

Does the system recognize the truck is in the low position? Or does it read out a different position while sitting low?

 

[BOB F]

The airbag recall should be free.

Does the system recognize the truck is in the low position? Or does it read out a different position while sitting low?

When I start the car it's shows off and L. If I push N it blinks N but then blinks off. The car doesn't change. It's in L position

There is fluid in the tank, I haven't discerned if I hear a pump yet.

I just had another Lexus at the dealer for an airbag recall and they did a "complementary" inspection ,es350, and presented me with $8000 worth of stuff to do. I'm expecting the same deal with this vehicle as well. It will be interesting to see what they say. Full system replacement?

Where do I start troubleshooting this?

 

[PADDO]

Start with ensuring the system isn't in an "inhibited mode" i.e. Doors shut, foot not on brake for more then 5 seconds etc. Fuses, DTCs, just follow the FSM recommendations for "AHC fails to operate. I'll bet it's something simple, usually is.

 

[BOB F]

Start with ensuring the system isn't in an "inhibited mode" i.e. Doors shut, foot not on brake for more then 5 seconds etc. Fuses, DTCs, just follow the FSM recommendations for "AHC fails to operate. I'll bet it's something simple, usually is.

Thank you.

Can you point me to where I can get the FSM?

 

[PADDO]

You can buy time on Toyota's Tech site and download e manuals or just sections, or try eBay for hard copy. Here's a bit to get you started. Have a look at the Lexus owners site and register the VIN and you might see what the last Lexus dealer did or didn't do, what services the PO declined etc. sometimes they will reference DTCs, a repair strategy and "customer declined repair". That's usually when they trade/sell because a dealer has said it's a $3k-$4k repair when it could just be a $150 sensor. There are very very few positive reports of dealers accurately and competently diagnosing these system, something to bare in mind. Also DTCs are often helpful, but may not necessarily tell the full story and should be looked at holistically.
The biggest issue with trying to fault find this, or any, system is not starting from a known functional reference point and not knowing what "good" actually looks like. The file named AHC pre check is a third part verbatim copy of DI 208 that's called up regularly in the problem tables. Inspect the basics, pull any DTCs, note them down, clear them and go from there....
Edit: Just to confirm the OFF switch, when pushed in for a second or two, doesn't change the status (to NOT OFF i.e. ON) and have you driven it and the vehicle still stays in L? If the system is turned OFF the height control won't function whilst stopped but will turn itself back on and raise to N when driven if all is working as designed.

 

[BOB F]

You can buy time on Toyota's Tech site and download e manuals or just sections, or try eBay for hard copy. Here's a bit to get you started. Have a look at the Lexus owners site and register the VIN and you might see what the last Lexus dealer did or didn't do, what services the PO declined etc. sometimes they will reference DTCs, a repair strategy and "customer declined repair". That's usually when they trade/sell because a dealer has said it's a $3k-$4k repair when it could just be a $150 sensor. There are very very few positive reports of dealers accurately and competently diagnosing these system, something to bare in mind. Also DTCs are often helpful, but may not necessarily tell the full story and should be looked at holistically.
The biggest issue with trying to fault find this, or any, system is not starting from a known functional reference point and not knowing what "good" actually looks like. The file named AHC pre check is a third part verbatim copy of DI 208 that's called up regularly in the problem tables. Inspect the basics, pull any DTCs, note them down, clear them and go from there....

Thank you so much for the help.

I am assuming in order to pull DTC i need techstream? I don't have that yet.

I have an appt. Monday for the airbag recall and they are going to do their "inspection" of course. I'll post what they say unless I fix it in the next couple days which I doubt.

 

[PADDO]

I am assuming in order to pull DTC i need techstream? I don't have that yet.

You can do it manually. Step 1b of the pre check PDF.

 

[BOB F]

You can do it manually. Step 1b of the pre check PDF.

Ok thanks.

I just went out to try and hear something and I was mistaken, the reservoir is bone dry!

Should I try to bleed/add fluid first?

 

[tacoduck]

Paddo is the guy, but I would probably add fluid and see what happens.

 

[PADDO]

Ok thanks.

I just went out to try and hear something and I was mistaken, the reservoir is bone dry!

Should I try to bleed/add fluid first?

You'll need adequate (some) fluid to move forward with anything so top off well above min level (you're at L so it'll draw down if you get it working) and hope there is some residual fluid in the pump and something happens. If indeed it is bone dry then your pump will in all likelihood need to be force primed by making it run manually. You do this by doing what's called the "active test" I've posted that procedure previously (search active test or air bleed the pump posts by me) and it's also in that pre check pdf. The bigger question is "where did the fluid go?" Be prepared to find a blown hydraulic line, particularly if the undercarriage is rusty. Hopefully not, but this might be where the PO got the $$$ estimate and decided to move on. If you have a burst line then you can usually locate clean serviceable used takeoffs from mud members for the cost of shipping.

 

[BOB F]

You'll need adequate (some) fluid to move forward with anything so top off well above min level (you're at L so it'll draw down if you get it working) and hope there is some residual fluid in the pump and something happens. If indeed it is bone dry then your pump will in all likelihood need to be force primed by making it run manually. You do this by doing what's called the "active test" I've posted that procedure previously (search active test or air bleed the pump posts by me) and it's also in that pre check pdf. The bigger question is "where did the fluid go?" Be prepared to find a blown hydraulic line, particularly if the undercarriage is rusty. Hopefully not, but this might be where the PO got the $$$ estimate and decided to move on. If you have a burst line then you can usually locate clean serviceable used takeoffs from mud members for the cost of shipping.

I thought the same about the loss of fluid. It had to go somewhere. I would assume if there is a leak/breakage, short of visually identifying it the only way to know is to fill the system and watch for leaks?

Im going to get it up on a lift and do a good visual inspection of everything.

I really appreciate the excellent responses. Thank you.

 

[PADDO]

Having a good look up on a hoist is the way to go. The main valve block is on the inner frame, drivers side mid frame. That's the epicenter of the system's plumbing and probably a good place to start. Good luck, hopefully it's a simple repair and your purchase price reflected the potential to do a little work on the AHC system.

 

[BOB F]

You can do it manually. Step 1b of the pre check PDF.

Is DLC1 the OBD port? If not, where is it?

 

[PADDO]

Under the dash is DLC3, DLC1 is under the hood, PS inner fender and is labeled DIAGNOSTIC.

 

[BOB F]

Under the dash is DLC3, DLC1 is under the hood, PS inner fender and is labeled DIAGNOSTIC.

I am getting DTC 62

I haven't added any fluid yet

 

[PADDO]

C1762 is to be expected if your system is out of fluid. Its "pump pressure anomaly". Sometimes spurious, rarely anything serious clear it and get some fluid in the system. It's very likely you'll need to force prime the system as I mentioned earlier.

 

[BOB F]

C1762 is to be expected if your system is out of fluid. Its "pump pressure anomaly". Sometimes spurious, rarely anything serious clear it and get some fluid in the system. It's very likely you'll need to force prime the system as I mentioned earlier.

Thank you.

Just had friend with a shop put it on a lift for me. We walked around and visually looked at what we could. No signs of damage or corrosion. Lines look great with enamel coating intact, etc. Saw the block you mentioned on the left side. All looks intact.

His comment, buy the fluid and we'll see were its leaking from. That will be my next step.

 

[BOB F]

I put fluid in. About s quart overall. Cycle ignition on an off. Saw level drop. Pump wax working. Heights adjust and stay there !!!

I'll bleed the system as well

Thank you so much for the support!!