AHC pump out? (1 Viewer)

suprarx7nut

The YotaMD Guy
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Sep 28, 2010
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Colorado
I have seen 1.x was able to program key, customize telescoping, door lock, window and sunroof settings.
The 1.x cable I own was able to program my key, disable my DRLs, and stop that annoying auto-telescope wheel from activating. I have a 01LX that doesn't have TPMS, and I have read multiple places that the V1.x cables don't allow TPMS manipulation.

I think for SURE the 200 series would benefit from the V2.x cable. On the Hundys, it is perhaps only a benefit for those folks with TPMS and maybe some more advanced key programming requirements?

Ah, ok, good info. This makes me think the 06-07s might be different then. With my 1.X cable I was able to program the customization features, but not able to "register" things like new keys or TPMS. With a 2.X firmware cable it all worked.

In that case, maybe the cable firmware 2.X is only meaningful for the 06+ crowd. 🤷
 
Joined
Jun 19, 2013
Messages
2,389
Location
Mobile, AL
It was the pump. I replaced with a good used pump and everything pumps up just fine. I can barely even hear the motor and pump. I took a few pics and plan to write up how I replaced the AHC motor/pump. When I get a laptop I plan to hook up Techstream and learn a little.

Thanks a whole lot for everyone's help especially 1sar39 for his generosity with supplying me with an excellent pump. I will be on the look out to see what I can pass on to another Mud Bud in need.
 
Joined
May 31, 2003
Messages
8,582
It was the pump. I replaced with a good used pump and everything pumps up just fine. I can barely even hear the motor and pump. I took a few pics and plan to write up how I replaced the AHC motor/pump. When I get a laptop I plan to hook up Techstream and learn a little.

Thanks a whole lot for everyone's help especially 1sar39 for his generosity with supplying me with an excellent pump. I will be on the look out to see what I can pass on to another Mud Bud in need.

How many miles on the failed pump?
 
Joined
Jun 19, 2013
Messages
2,389
Location
Mobile, AL
Few pics of old pump with guts open. That jelly fluid is one year and 11 months old.

13910CFC-B038-4A3C-8BF1-5FE97F5F8F45.jpeg
96138D21-F3B9-4939-A83F-5A2F3C208231.jpeg
95CE3AFE-FB89-4058-974B-FBEA7D8A470D.jpeg
 

ramangain

Clarksonian disciple
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Atlantis
Good example of why changing AHC fluid is necessary so that gunk doesn't build up like that.

I'd wager that is years of buildup, not just the stuff that built up since the most recent fluid change.
 
Joined
Dec 6, 2016
Messages
316
Location
Brisbane, Australia
Few pics of old pump with guts open. That jelly fluid is one year and 11 months old.

View attachment 2452451View attachment 2452452View attachment 2452454

Thank you @BullElk ! The very helpful but worrying pictures of accumulated ‘gloop’ made me wonder whether I had the same problem – or worse, whether a similar accumulation of ‘gloop’ was occurring elsewhere in the AHC system beyond the Pump -- such as the Return Valve, Attenuator, Control Valve Assembly, various solenoid valves, step motors and valves in the Damping Force Control Actuators (to which the ‘globes’ are attached) etc, etc.

I had already replaced my LC100 AHC Pump (whole pump-motor-tank assembly) and Height Control Accumulator with new Toyota/Lexus units. This was done in response to an occasional DTC 1751 and a persistent DTC 1762 with vehicle very slow to raise from “LO” to “N” – 30 to 40 seconds, and for long term reliability. [DTC 1751 = Pump and Motor Circuit; DTC 1762 = Fluid Pressure Abnormality].

For interest, I disassembled my old AHC Pump but found only very light accumulations of very fine dark material, similar to that seen on the inside of my AHC tank after 14 years, despite many AHC Fluid changes. These accumulations did not seem sufficient to be causing a problem. I recalled insights from @PADDO which were concerning the strainers within the AHC Pump at his post #16 and onwards in that thread.

I located these pressed-in strainers near the pump ports as shown by a ‘star’ in the following pictures but was unable to remove the strainers for close inspection. Blowing through the strainers did not suggest that they were obstructed.

A further search revealed a post concerning an AHC Pump on a LX570 by IH8MUD Member @Zel. The pictures of the LX570 AHC Pump itself looks very similar to the LC100/LX470 AHC Pump even though the rest of LX570 AHC system is very different. @Zel was seeking advice about replacement strainers (helpful pictures included) but received no replies.

The pictures below show my AHC Pump as disassembled and without cleaning. The component parts appear to be in excellent condition.

The pictures below are offered for interest as the internals of the AHC Pump are rarely seen.

The AHC Pump is a small, simple high pressure gear displacement pump and is well-described with diagrams at FSM reference: https://lc100e.github.io/manual/ (follow tabs starting at the top:
New Car Features > CHASSIS > Suspension > Active Height Control Suspension).

Sad to report – in my case even with a complete new AHC Pump assembly and a new Height Control Accumulator, the vehicle remains slow-to-raise from “LO” to “N” and DTC 1762 still persists – so I am missing the point somewhere! This will be the subject of a separate post seeking advice.

Meanwhile, any comments are very welcome ….

A series of pictures follows, spread across this post #69 and the next post #70:

AHC Pump Diagram From FSM
AHC Pump - FSM Diagram.JPG


AHC Pump Cover Removed
AHC Pump - Cover removed.jpg


Initial Disassembly
AHC Pump - Disassembled 1.jpg


Gear Pump Exposed
AHC Pump - gears exposed.jpg


Complete Disassembly
AHC Pump - Disassembled 2.jpg
 
Last edited:
Joined
Dec 6, 2016
Messages
316
Location
Brisbane, Australia
Thank you @BullElk ! The very helpful but worrying pictures of accumulated ‘gloop’ made me wonder whether I had the same problem – or worse, whether a similar accumulation of ‘gloop’ was occurring elsewhere in the AHC system beyond the Pump -- such as the Return Valve, Attenuator, Control Valve Assembly, various solenoid valves, step motors and valves in the Damping Force Control Actuators (to which the ‘globes’ are attached) etc, etc.

I had already replaced my LC100 AHC Pump (whole pump-motor-tank assembly) and Height Control Accumulator with new Toyota/Lexus units. This was done in response to an occasional DTC 1751 and a persistent DTC 1762 with vehicle very slow to raise from “LO” to “N” – 30 to 40 seconds, and for long term reliability. [DTC 1751 = Pump and Motor Circuit; DTC 1762 = Fluid Pressure Abnormality].

For interest, I disassembled my old AHC Pump but found only very light accumulations of very fine dark material, similar to that seen on the inside of my AHC tank after 14 years, despite many AHC Fluid changes. These accumulations did not seem sufficient to be causing a problem. I recalled insights from @PADDO concerning the strainers within the AHC Pump concerning the strainers within the AHC Pump at his post #16 and onwards in that thread.

I located these pressed-in strainers near the pump ports as shown by a ‘star’ in the following pictures but was unable to remove the strainers for close inspection. Blowing through the strainers did not suggest that they were obstructed.

A further search revealed a post by IH8MUD Member @Zel concerning an AHC Pump on a LX570. The pictures of the LX570 AHC Pump itself looks very similar to the LC100/LX470 AHC Pump even though the rest of LX570 AHC system is very different. @Zel was seeking advice about replacement strainers (helpful pictures included) but received no replies.

The pictures below show my AHC Pump as disassembled and without cleaning. The component parts appear to be in excellent condition.

The pictures below are offered for interest as the internals of the AHC Pump are rarely seen.

The AHC Pump is a small, simple high pressure gear displacement pump and is well-described with diagrams at FSM reference: https://lc100e.github.io/manual/ (follow tabs starting at the top:
New Car Features > CHASSIS > Suspension > Active Height Control Suspension).

Sad to report – in my case even with a complete new AHC Pump assembly and a new Height Control Accumulator, the vehicle remains slow-to-raise from “LO” to “N” and DTC 1762 still persists – so I am missing the point somewhere! This will be the subject of a separate post seeking advice.

Meanwhile, any comments are very welcome ….

View attachment 2455878

View attachment 2455879

View attachment 2455880

View attachment 2455884

View attachment 2455887

Further pictures in the series started at my previous post #69 ....

Pump Inlet Port and Strainer Position
AHC Pump - Inlet Port and Strainer.jpg


Pump Outlet Port Position
AHC Pump - Outlet Port.jpg


Pump Outlet Strainer Position
AHC Pump - Second Strainer.jpg


Pump Strainers (not removed by IndroCruise, picture by @Zel)
AHC Pump - Strainers by Zel.jpg
 
Last edited:

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