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AHC problem

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Old 04-19-18, 01:47 PM
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Dxta
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Default AHC problem

I'm new here, HI!
pls have got a AHC problem with my Lexus 570, 2008.

HISTORY OF PROBLEM: Right rear shock had leaked, and whenever I'm driving on high ways, the truck shakes. Kinda unstable, as if trying to gain some equilibrium.

Each time the engine is started, the AHC pump sounds at the rear, and the rear shocks tends to rise, without any noticeable increase in the front shocks.

The "check 4wd AHC system comes on" on the dashboard. Immediately this light is lit on the dashboard, the AHC pump immediately stops working.

WHAT HAVE YOU DONE? Well, I ordered for new rear OEM shocks, and had them replaced; got 2.5L of hydraulic fluid, and topped off the level, and then bled the whole AHC actuators, without luck. Used Toyota techstream software to clear the AHC code, yet still the same thing.

Scanned code was C1763: Abnormal oil pressure of motor pump.

I did order for a used AHC pump, from a junk yard over here, and when I did replaced it, the problem was still there. No change at all.

I have checked all the fuses and relays associated with the AHC system, and they're all OK.

WHAT DO YOU WANT US DO FOR YOU? I need your help guys, in finding out what actually is the problem? Has anyone here, experienced something similar as this? Kindly drop your suggestions pls.


Dxta
Old 04-20-18, 07:31 AM
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UCrazyKid
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what pressures is the Techstream reading? Are they within spec? Could it be a sensor is giving bad information even though the mechanicals are OK?
Old 04-24-18, 01:44 PM
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Max707
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Go on to www.ih8mud.com. And as your question in the 200 series secti

Last edited by Max707; 04-24-18 at 01:48 PM.
Old 04-24-18, 03:48 PM
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hankinid
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Originally Posted by Max707
Go on to www.ih8mud.com. And as your question in the 200 series secti
User PADDO there (and also here) knows more about AHC workings than anybody I've seen here or there, and that includes Toyota and Lexus dealers. You might send him a PM.

Steve
Old 05-01-18, 06:57 AM
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electro992
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Attached are the factory service manual pages for C1763. I don't remember for sure, but I think I got a code like this once when I was bleeding the system and let the fluid get too low in the reservoir. Fix was the re-bleed and cycle the system a few times, then bleed again to ensure all the air was out. When the code is set the system will not respond to the switches in the car, but you can use the Techstream "Active Test" section to cycle the height modes for bleeding.
Old 05-01-18, 07:05 AM
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electro992
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Bleeding instructions

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