Changing out the AHC suspension fluid? (1 Viewer)

[Flipped Bezel]

Before I do all of that I do want to check the pressures, but I'm unsure as to what units will actually work on an Aussie 2005 model. Most scanner websites seems to say only 2006 on-wards. I checked with an Ebay site about the TOYOTA Techstream TIS V10 MINI VCI USB Interface OBD2 Car Diagnostic Cable unit ($50) and he says it will work provided I have Windows XP. I did notice that a few people on here did mention that so I know there are a number of ways around this issue. However, he recommended the AUTEL AutoLink AL619 OBD2 ABS AIRBAG Diagnostic Car Scanner which is +4 times the price ($240). Have any Aussies on here had any success with any units and have any recommendations?

I got my Mini VCI cable/software off of Amazon a year or so ago. This is the one I bought:Amazon.com: Docooler Mini VCI Car OBD Diagnostic Scanner OBD2 USB Interface Scan Tool for TOYOTA TIS Techstream Diagnostic Cable & Software: Cell Phones & Accessories

I am running Techstream version 10.10.018. It took me a couple of tries and a little bit of reading on different forums before I was able to get it working on an old windows XP laptop. It seems that I was installing programs in the wrong order at first.

It was nice to be able to customize some vehicle settings with it once it was up and running. It was also useful for reading and clearing any DTC's that have occurred.

 

[casdawg]

Ok thanks Flipped Bezel. I bought a cable from ebay saying it supported 32-bit and 64-bit... took that with a grain of salt. Couldn't seem to get it working with Windows 8.1 so reverted to running a virtual machine with Windows XP professional. Works a treat and now have pressure readings of FRONT: 10.2, rear: 8.2, accumulator: 10.7.
My measurements on the low and high settings on the fluid reservoir are borderline- just 7/8 (a little hard to be sure as my reservoir is a little full). I'll bleed a bit more and see how that goes. I might just be needing some new spheres on the front (at least)...but will try everything else first.
Looks like it is time to crank the torsion bars and see how much things can improve.

 

[Dannyboy lx470]

Do you do the bleeding in N Height ?.

 

[casdawg]

Yes, bleeding at N height. Fluid coming out is much clearer now, and I have readings of 7.1 Front, 6.9 rear. However, it still feels bouncy at the front - going over a speed hump and the front acts like its on a spring. Its probably much better than when I first started but still present.

 

[PADDO]

Yes, bleeding at N height. Fluid coming out is much clearer now, and I have readings of 7.1 Front, 6.9 rear. However, it still feels bouncy at the front - going over a speed hump and the front acts like its on a spring. Its probably much better than when I first started but still present.

With borderline charge left in your spheres you'll find better damping with front pressure around 6.7ish and the rear closer to, or even lower then, 6MPa.

 

[casdawg]

Ok so it has only taken a few months to get there. I have installed new spheres and the ride is amazing!!! No more bouncing around like there is a kangaroo under the bonnet. Readings are now: Front: 6.5, rear: 7.4, accum: 10.6 Looks like the rears are a bit high and front a little low. So I might wind out the torsion bars a little to see if I can get better numbers - although I would not be surprised if the rear springs need an update.

One thing I did notice is that I now get an error code C1762. Followed the thread on that one and I might leave that one for an expert.

 

[DenverCruiser]

Now that the AHC fluid is only sold in 1qt bottles, how many are needed? My local Lexus dealership has 3 qts avaiable @ $15 each. Toyota dealership has none. I also asked the service dept how much they charge (just curious) to service it, they didn't have it in their computer (so I assume do not regularly perform this at all?) but said it would be ~$200.

 

[geanes]

Now that the AHC fluid is only sold in 1qt bottles, how many are needed? My local Lexus dealership has 3 qts avaiable @ $15 each. Toyota dealership has none. I also asked the service dept how much they charge (just curious) to service it, they didn't have it in their computer (so I assume do not regularly perform this at all?) but said it would be ~$200.

@DenverCruiser

2.5 quarts. NEVER pay a dealership to do this. This is a 1/2 banana job. Here's the best write up on the AHC fluid exchange by resident AHC expert Paddo:

Edited for extra detail.

Here's a quick, easy and efficient 1 can (or 3 bottle) AHC fluid exchange/bleed procedure. By following this process you are very unlikely to get yourself into trouble by accidentally bleeding too much fluid. Furthermore, it's not at all wasteful of new fluid as you remove a considerable amount of the old fluid/gas/air and recharge the whole system with fresh fluid in just one cycle. No wasteful start/stop/bleed/start/stop...... process.

The benefits of periodically changing out the AHC/AVS systems' fluid can't be overstated as this mineral based working oil degrades with time, temperature and use. Fluid viscosity changes, anti wear, anti rust, anti foaming, anti oxidation additives deplete and the fluid picks up particulate and other contamination. Nitrogen from the accumulators permeates into the system over time and virtually all hydraulic systems will allow air to come out of fluid solution and form bubbles with use and time. The combination of degrading fluid and entrained gases affects damping performance and ultimately can't promote the maximum service life of the system. FWIW I change out the systems fluid at half the recommended service interval, or about 30k miles/3 years.

Materials required. One can of fluid (Toyota suspension fluid, AHC 08886-01805) or three of the new 1L bottles, clear pvc pipe that's a snug fit (3/16 ID) on the bleeders, 10mm spanner/box wrench/crows foot and a suitable waste fluid container.

This process assumes the fluid level in the reservoir is between max and min when the vehicle is at Normal height before commencing and the 5 bleeder points aren't frozen due to corrosion. If corrosion is an issue then consider spraying a penetrating oil (PB Blaster etc) on the bleeders several times over a few days beforehand and use a good quality 6 point 10mm socket wrench. If you can't open the bleed points due to rust then an option would be to drive the AHC system down to the bump stops (lower then L and returning the maximum amount of fluid back to the reservoir for removal) in Active Test Mode and remove/replenish the fluid from the reservoir and not attempt bleeding at the 5 points. Not optimal but probably better than doing nothing. Always clean around the reservoir cap and the spout of the AHC fluid can before opening and avoid introducing any contamination into the reservoir.

This maintenance activity needs to be done with the vehicle on flatish, level ground and not on a lift or with the wheels off the ground as you need the vehicle's weight to compress the shock actuators down to the bump stops to remove the maximum amount of old fluid. Don't get under the vehicle, you access the bleed points on the outer frame rails.

1. Lower the vehicle to LOW and wait 30 seconds for the AHC system to settle and then turn the vehicle OFF, do not restart the engine until step 8. The fluid in the reservoir will now be at its highest level. Using a turkey baster or similar suction device remove as much of this old fluid as practical from the reservoir. The amount removed should equal, or be slightly over, 1 liter [if you were between Max and Min at N].
2. Pour the the entire contents of a 2.5 liter can [or 2 1/2 x 1 liter bottles] of new fluid into the emptied reservoir. It will be very close to completely full.
3. Now we know that the reservoir's "normal" contents is ~ 1 liter (vehicle in L when fluid level is correct at N) and you have just filled it with 2.5 liters so you don't want to drain/bleed more than 1.5 liters or else you may end up with insufficient fluid on completion.
4. Starting at the height accumulator (12 inch long cylinder on DS outer frame rail, between front and rear damper assemblies) connect your drain tube, crack the bleeder and commence draining fluid, closing the bleeder as fluid flow stops. You should drain ~0.3 liters.
5. Move to the front LH damper assembly, connect tube, crack the bleeder and drain until the front has dropped down to the bump stops. Both sides of the vehicle will lower together (because they are hydraulically connected) and you should drain ~0.4 liters. Again close the bleeder as fluid flow stops.
6. Move to the rear LH damper assembly, connect tube, crack the bleeder and drain until the rear is close to/on the bump stops. Both sides will lower like the front did and you should drain ~0.3 liters. Again close the bleeder as fluid flow stops.
7. Now you should have drained very close to 1 liter (0.3+0.4+0.3 for healthy damper accumulator spheres; if you have degraded or blown spheres then you'll likely drain less fluid as there's limited/no nitrogen charge to expel the spheres fluid contents) leaving you about 0.5 liters "excess" in the reservoir.
8. Start the vehicle, let it idle for 30-60 seconds and then press the UP button to raise to NORMAL height. The whole system will refill and recharge with new fluid from the reservoir and the level in the reservoir will be drawn down to slightly over the max line if everything has gone as expected.
9. Turn the vehicle OFF and do a small, quick bleed on the PS front and rear damper assemblies just to check that there isn't any gas trapped. You don't need to remove very much at all from the PS as essentially all available fluid (there will always be a small residual in each shock actuator/damper that we can't access) is forced out when you do the DS dropping the vehicle down to the bump stops.
10. You're done, confirm that the reservoir fluid level is correct - between max and min at N height with the engine running. There is nothing wrong with leaving the level slightly over the max line.

As long as you don't drain more than 1.5 liters you can't mess up and accidentally draw air into the pump/system through the reservoir or be left short of fluid.

This approach is simpler than others, but slightly more elaborate than the FSM. It is intended to remove as much old fluid as practical in a quick and efficient manner. It doesn't waste new, fresh fluid like the drain/start/stop/drain/start etc method. Hopefully this method fills an information gap by associating approximate quantities drained to the height accumulator and the front/rear hydraulic circuits and gives people the confidence to undertake this simple yet critically important maintenance procedure.

 

[DenverCruiser]

Like you said, 1/2 a banana job. Super easy. Thank you for posting that, I knew I had seen it before but did not see it in this thread. Oddly enough, although the fluid in the reservoir and height accumulator was nasty/black the fluid in the globes wasn't bad at all (not sure what that is about). Ideas?

Advice for others. Make sure your turkey baster (or whatever you have to use) can reach the very bottom of the tank before you start. Mine would not so I had to finish using a syringe and tubing which took much longer.

The slight creek/pop when going up and down is now gone and it does seem to move faster and more smoothly.

 

[geanes]

I used a $9 hand transfer pump from Home Depot to empty my reservoir. Worked very well.

 

[lcdude]

To run the pump manually, do the "Active Test".

On the DLC3, connect CG to Ts (pin 3);
(See previous post. Pin 3 is just below pin 4, in the left row of Dandon's pic linked to above. Meaning pin 1 is in the bottom left corner in that photo. And pins 3 and 4 are the only two neighboring pins with metal in them)
Switch the ignition on;
Depress the "Down" button of the Height Select Switch 5 times or more within 5 secs;
Now the AHC "OFF" indicator will start flashing at 0.25 secs interval.

Then you can start the engine (or do it when you turn ignition on)
Set the shock-setting switch to "Comfort" (Also called the "Damping Mode Select Switch)

Then, you can raise and lower the front by using the Up and Down buttons of the AHC Height Selector.
To control the rear suspension instead, you hold down the "Height Control Off" switch simultaneously.

WARNING: Do not raise the vehicle higher than the "Hi" position.

Have fun.

Hi - I cannot get the AHC "OFF" indicator to start flashing. My wire seems to be in the right pins, and I follow yours as well as the attached instructions to turn on the engine and press the Down button five (or even 6) times after the engine started. What am I doing wrong? I know my wire is good as I use it for my FJ80 diagnostics.

 

[PADDO]

Hi - I cannot get the AHC "OFF" indicator to start flashing. My wire seems to be in the right pins, and I follow yours as well as the attached instructions to turn on the engine and press the Down button five (or even 6) times after the engine started. What am I doing wrong? I know my wire is good as I use it for my FJ80 diagnostics.

View attachment 1878522 View attachment 1878524

Use Ts and E1 in the DLC1 connector under the hood as it is much easier to access and the sockets are clearly labeled. E1 in DLC1 = Cg in DLC3 and Ts is Ts.

 

[lcdude]

Use Ts and E1 in the DLC1 connector under the hood as it is much easier to access and the sockets are clearly labeled. E1 in DLC1 = Cg in DLC3 and Ts is Ts.

Thanks, PADDO. I think it worked. I definitely heard the pump go off and the front of the truck went up a bit, but the height indicator stayed at N. I guess this is how it's supposed to work.

 

[PADDO]

Raising the front or rear in the active test mode is quite slow because you’re relying on just the pump output without being augmented by the height accumulator’s output. If you hold the up button in it’ll raise quite high.

 

[lcdude]

Raising the front or rear in the active test mode is quite slow because you’re relying on just the pump output without being augmented by the height accumulator’s output. If you hold the up button in it’ll raise quite high.

Thanks. I think instructions said hold for 10 sec. Should I hold longer? I see a note not to raise higher than H, but nowhere does it say how raising above H would look (ex., Will I go above H if I hold longer than 10 seconds?) When to stop holding? Don’t want to burn the pump.

 

[PADDO]

These instructions are riddled with inconsistencies, hold in for longer than 10 seconds and the front creeps up slowly. Stop raising when it’s about +2 inch over N, if N is 19,75 in hub center to fender bottom. There are several AHC procedures in the book that, if you follow verbatim, won’t work - little things like saying turn ignition ON but you actually have to start the engine.
Do you have a defect or are you just experimenting?

 

[lcdude]

These instructions are riddled with inconsistencies, hold in for longer than 10 seconds and the front creeps up slowly. Stop raising when it’s about +2 inch over N, if N is 19,75 in hub center to fender bottom. There are several AHC procedures in the book that, if you follow verbatim, won’t work - little things like saying turn ignition ON but you actually have to start the engine.
Do you have a defect or are you just experimenting?

I figured inconsistencies were in place. Will try holding for over 10 sec.

I am looking to be proactive with potential air in the AHC pump/hydraulics. Was recently changing AHC fluid, and could have allowed the reservoir get empty for few seconds (was gaging by what I could see from the outside vs. looking inside). So, want to follow this procedure to bleed any potentially trapped air out of pump and lines. The truck adjusts hight well, so this is a precaution as well as want to eliminate any potential long-term tear on parts.


what

 

[PADDO]

I figured inconsistencies were in place. Will try holding for over 10 sec.

I am looking to be proactive with potential air in the AHC pump/hydraulics. Was recently changing AHC fluid, and could have allowed the reservoir get empty for few seconds (was gaging by what I could see from the outside vs. looking inside). So, want to follow this procedure to bleed any potentially trapped air out of pump and lines. The truck adjusts hight well, so this is a precaution as well as want to eliminate any potential long-term tear on parts.


what

This active test procedure is designed to force start the pump if it’s airlocked with bulk air. Yours seems to be running so this process isn’t really achieving you anything or solving any issue. If you have entrained bulk air in the system then that will be predominantly trapped in the outer extremities of the system, if it hasn’t been returned to the reservoir and dissipated, and needs to be bled off via the five bleed points. Running the pump in active test is a good learning experience and you can slam the front down and Jack the rear up to look like a hot wheels 4x4 but it doesn’t bleed the system as such. I’d just cycle the system through it’s normal ranges and check for air at the bleeders.

 

[lcdude]

This active test procedure is designed to force start the pump if it’s airlocked with bulk air. Yours seems to be running so this process isn’t really achieving you anything or solving any issue. If you have entrained bulk air in the system then that will be predominantly trapped in the outer extremities of the system, if it hasn’t been returned to the reservoir and dissipated, and needs to be bled off via the five bleed points. Running the pump in active test is a good learning experience and you can slam the front down and Jack the rear up to look like a hot wheels 4x4 but it doesn’t bleed the system as such. I’d just cycle the system through it’s normal ranges and check for air at the bleeders.

Superb, thanks. Exactly what I was planning to do next. Waiting on the AHC fluid to arrive at my dealership. Plan to bleed 1 L or so total unless more fluid has entrapped air.

 

[cumminsBase]

How can I remove air from the system?

I was bleeding the system yesterday, and I let the reservoir run dry and suck air in.
How can I bleed this air out of the system?
If there a FSM procedure?
Or even better, a ih8mud procedure?