AHC Sensor Adjustment for Lift (1 Viewer)

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I need some help. I bought a LX470 and put an ARB combo bar on which is about 275lbs or so. I flushed out the AHC fluid using the @PADDO method. I shortened the front sensors all of the way but did not cut them and I moved the rear up all of the way. I added 30mm spacers to the rear. So far so good. When I hooked up tech stream, my initial front pressure was 11.0 and the rear was 7.8, whoa. So I gave the torsion bars 8 turns and got them down a few points each. So then I gave her 13 more turns each which bottomed the bolts out. The pressures are now 6.7 for the front and 6.3 for the rear. Am I ok now? Even with the bars cranked all of the way? Thank You

Ya its fine from my understanding. If you need more torision you can reindex the torision bars.
 
Ok, a few more questions :frown:. After I did the AHC lift, the front sensors are FL -.3 and FR 0 with both joints moved to the top and shortened. Would that have anything to do with why the truck sits 1/2" lower from one side to the other? Should I adjust them to be equal?
 
Ok, a few more questions :frown:. After I did the AHC lift, the front sensors are FL -.3 and FR 0 with both joints moved to the top and shortened. Would that have anything to do with why the truck sits 1/2" lower from one side to the other? Should I adjust them to be equal?
You need to crank the torsion bars to get your side to side height dialed in. I only did about a 1" sensor lift up front and I think I did about 6 turns on the passenger and 15 turns on the drivers. It is now sitting level at all 4 corners and all AHC pressures in spec. Your amount of turns will also vary based on amount of miles on your vehicle and how worn your TB's are. Hope this helps.
 
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Thanks, I'm going on a big trip so I want to get this right. Both TBs are maxed out right now so one will have to come back. How does the sensor height adjuster value work in relation to torsion bars or does it? If I slam the sensors up and tighten them on both sides but they are not equal values in TS, do they need to be?

You need to crank the torsion bars to get you side to side height dialed in. I only did about a 1" sensor lift up front and I think I did about 6 turns on the passenger and 15 turns on the drivers. It is now sitting level at all 4 corners and all AHC pressures in spec. Your amount of turns will also vary based on amount of miles on your vehicle and how worn your TB's are. Hope this helps.

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Thanks, I'm going on a big trip so I want to get this right. Both TBs are maxed out right now so one will have to come back. How does the sensor height adjuster value work in relation to torsion bars or does it? If I slam the sensors up and tighten them on both sides but they are not equal values in TS, do they need to be?



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I have only had my LX for about 6 months, so I am new at the whole AHC thing. I learned the little I know off this forum. PADDO is the AHC expert and hopefully he will see this post and chime in.
 
Tried the Sensor lift the front went smoothly and worked. The rear not so much I moved . I am not sure what I did but now it will adjust the height in the front but not the rear. Slide the adjustment to the top now it just sits lower. When I try and adjust it will either just lift the front or blink and stay in neutral. When I try driving it just blinks AHC off. I can take pictures in the morning. But I have no corrosion of any kind so I am at a loss. Maybe it is the sensor but I doubt it. I get the code C1713 from tech stream so maybe. But you think it would have acted up prior.
 
Tried the Sensor lift the front went smoothly and worked. The rear not so much I moved . I am not sure what I did but now it will adjust the height in the front but not the rear. Slide the adjustment to the top now it just sits lower. When I try and adjust it will either just lift the front or blink and stay in neutral. When I try driving it just blinks AHC off. I can take pictures in the morning. But I have no corrosion of any kind so I am at a loss. Maybe it is the sensor but I doubt it. I get the code C1713 from tech stream so maybe. But you think it would have acted up prior.
Is your fluid level low? Maybe not enough fluid to get to the desired height? Just trying to toss out an idea that could be an easy fix. Worth at least looking at.
 
Is your fluid level low? Maybe not enough fluid to get to the desired height? Just trying to toss out an idea that could be an easy fix. Worth at least looking at.

I have since ripped out the AHC system so not sure. I could have gone with a new sensor but decided for my needs that I would replace it.
 
Does anyone know of a step-by-step guide how to set the AHC to stock values?
 
I installed rear King Springs and now my rear AHC pressure is reading 4.9. Should I adjust the rear sensor down to increase the rear AHC pressure to spec? Is that even possible? Should i just leave it alone and wait for the springs to weaken on their own over time? Thanks for any input/thoughts.

Was there any answer for this? Having the same problem.
 
Move it towards the top of the slider to increase pressures (and height). But if your height is correct, then only a weaker spring could increase the pressures
 
I ended up turning the front torsion bar to get the front pressure in spec and that resulted in the back numbers getting within spec
 
I ended up doing the ahc lift today and did not cut the front heim joints. I just shortened them on both sides as far as they could go and moved the top connecting point as high as I could on the slotted bracket.

For the rear I just moved the connecting point as high as I could on the slotted bracket.

From what I read in this thread the high mode should still work. Now if I hit the button from N it will not go to H. Has anyone else experienced this after the ahc lift if they didn't modify the sensors? Thoughts/suggestions?
 
I ended up doing the ahc lift today and did not cut the front heim joints. I just shortened them on both sides as far as they could go and moved the top connecting point as high as I could on the slotted bracket.

For the rear I just moved the connecting point as high as I could on the slotted bracket.

From what I read in this thread the high mode should still work. Now if I hit the button from N it will not go to H. Has anyone else experienced this after the ahc lift if they didn't modify the sensors? Thoughts/suggestions?

IMO shortening the fronts while also moving them to the top of the bracket is asking for too much (while the rear is only moved to the top of the bracket). IMO there is now a disagreement between the front and rear heights and that’s why it won’t raise.
 
I ended up doing the ahc lift today and did not cut the front heim joints. I just shortened them on both sides as far as they could go and moved the top connecting point as high as I could on the slotted bracket.

For the rear I just moved the connecting point as high as I could on the slotted bracket.

From what I read in this thread the high mode should still work. Now if I hit the button from N it will not go to H. Has anyone else experienced this after the ahc lift if they didn't modify the sensors? Thoughts/suggestions?
The AHC will not go into "H" if your neutral pressures are too high, as a safety feature. If you do a sensor lift, you are making the hydraulic component of the AHC work harder, thus increasing the pressure. In order to get it working correctly, you need to increase the load that the mechanical component of the AHC carries (the springs). Adjust your t-bars and shim/replace/airbag your rear springs as needed to get back within spec.
 

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