AHC Sensor Adjustment for Lift

hoser

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Added some pics. The first one shows the shortened heim joint. Notice the two stop-nuts are removed. The second pic shows the simple bracket made of of 1" aluminum stock. The new mounting point is slotted like the original.
front.jpg
rear.jpg
 

CTapia

 
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Feb 23, 2005
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Hoser,

Thanks for the pics! Did you say you have the aluminum stock on hand or I need to find it?

BTW: 315 TKOs arrived yesterday, I picked up the AHC fluid yesterday afternoon and the diff drop may be here sometime next week. Assuming the diff drop shows up before friday, are we on for friday the 4th? What else do I need to bring beside the :beer: ? :D
Picture 001.jpg
 

hoser

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CTapia, I have everything we'll need for the job. Yes, we are still on for Nov. 4th.
 
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Just a quick question. We did just the front and did not go extreme- about 1.7 inches. Why is an alignment needed after the adjustment? We did it with out even taking off the front tires.
 

hoser

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There is a small change in toe, caster and probably camber when you lift the IFS. My before/after alignment results weren't radically different. My toe was slightly out of spec and corrected. My caster couldn't be corrected back to spec though--currently around 1 degree (spec is 2.3 to 3.8 degrees).

So, I won't say it's completely necessary to align it afterwards but if you just bought some new tires, I'd say its money well spent.

UPDATE: By only adjusting the AHC sensors for lift, you'll lost some load carrying capacity. In order to retain the load carrying capacity, you should crank the front T-bars a bit and adjust the sensors some. The vehicle's load is shared partially by the spring/T-bar and partially by the AHC system. Having the correct balance between the two will yield the highest capacity and best ride. In the rear, you should be adding a spring spacer and adjusting the sensor if you want stock load carrying capacity. For best results, you'll need a brake pressure tool to accurately adjust the sensors.

Adjusting just the sensors for lift is not a bad thing. The AHC suspension is taking on a higher percentage of the weight and the springs less weight. Not really a bad thing as that is exactly what happens when you push "H" on your suspension height.

For more load capacity, you'll need to replace the springs/t-bars for ones with a higher spring rate.
 
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Apr 26, 2010
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Rear AHC adjustment thought...

AHC gurus...

On my 2006, I have three holes in the rear ahc control arm...
1, the arm is attached to.
2, empty hole in the middle
3, empty hole close to the unit itself(hard to see in photo)

Now the question is, could I put my connecting rod in the middle hole on the ahc arm to get more rear lift. Can this be done without stressing the sensor and the ahc unit due to the quick movements of the arm as a result of the change in angle.

This would eliminate the need for fabricating an extension as described in an earlier post. It appears that I would get almost the same result without the need for making a part.

Note: The photo is an old one before I adjusted the rear AHC to the top.
P1070307.jpg
 

hoser

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Yes, you will have raised the sensor at ride height but when the suspension is compressed, the sensor will move at a faster rate than when on the outer position. I'm not sure it will make a difference though.

The better solution would be to get a longer connecting rod. Measure the adjustable rods/joints on the front sensors and if it is long enough, then buy one of those.
 

Bryanl

 
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Jan 21, 2008
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Replaced all the rear control arms so I had to disconnect the arm that goes to the control arm. Now that it's all back together the AHC light blinks and it won't go to high or low from the neutral setting. Been searching but not a lot of info on when the AHC light starts flashing. Have tried adjusting it in the slot but nothing changes. Wondering if the jacking and lowering of the rearend to get the control arms off messed up the sensor before I disconnected it the adjusting arm? But don't see why the rear at full droop would be any different than when a tire shop jacks the whole vehicle up by the frame?
Will be ordering a minivci and techstream of amazon but don't have an xp computer. Scanned it with my handheld but nothing as well as disconnecting the battery. Fluid is full and was flushed a month ago.
Anyone have any suggestions on how to get it to what I think needs to reset or something?
 

PADDO

 
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image.jpg
I've dropped the rear axle a few times and never had a problem with the AHC, so I'd check the security of your connectors. By flashing it's saying "fail safe" for some reason, read your codes by shorting Tc and E1 in the dlc1 (under hood) connector as per the image. Clear codes by pressing the brake pedal 8+ times in <3 secs. See if that sorts it out.
Edit: doors shut, foot off brake etc conditions met for normal AHC operation? Just checking ;)
 
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Bryanl

 
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Jan 21, 2008
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99
Awesome info Paddo but still not fixed. Code 13 or I guess C1713 for Rear Height Sensor-shocker. I unplugged it and plugged it back in but still there. Performed the brake pedal reset and assume it worked as it beeped and some lights came on the dash and then went off.
Yes-doors closed, foot off brake-have flushed fluid but always worth checking.
I'll search for the fixes for the code 13. All I can think is that swapping the control arms the arm on the sensor got moved around and maybe out of range which damaged it possibly-just guessing. I'll double check the wiring going to the sensor since I was working in that area. Next I can pull the sensor off the other LX and see if that fixes the problem. I just think it went into failsafe for some reason during the work and thought that it would reset. FSM I have is for an 03 LC and don't find anything on the AHC to tell me more about the code. Didn't know if it takes 50 key cycles or something like that to end up resetting on it's own.
Thanks!
 

PADDO

 
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I think you're correct in that the sensor either was overextended and damaged or possibly wiring damaged. It's a pretty dumb, robust system, nothing like key cycles to reset it. Swap a new sensor and good luck!
 

Bryanl

 
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Jan 21, 2008
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Swapped sensors and immediately fixed it. Thanks again for the info. Gotta love taking a sensor off a truck with 283k and putting it on one with 82k. Haven't taken the sensor apart yet to see if it can be repaired.
Anyone ripping their AHC out I would like to buy/try their height sensors. I'll be on the lookout for one of these. I'll still try it on the 99 just to see if it works since it's torn apart getting ready for HIH.
 
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I'm thinking its Gotta be a sensor or a connection.
You haven't touched anything else in the system and it worked before you started your project.

Ray
 
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I'm thinking its Gotta be a sensor or a connection.
You haven't touched anything else in the system and it worked before you started your project.

Ray
Oops. Missed the fix above. I've been through the sensor situation before. It's a pain.
 

Bryanl

 
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Jan 21, 2008
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Little update. Seems weird. Put the rear height sensor from my 02 that was showing bad on the 99 and it works fine. I did take the sensor apart and it looked like brand new. Only possible thing I saw was maybe one of the thin copper looking tracing lines on the inside was flared up a little at the end. Think I tried to flatten it out but all I know is it's all working. Found an XP laptop on ebay for $50 and Techstream of Amazon so have the 99 within spec. Will check the 02 soon.
 
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Hoping to get some more information on the AHC lift options.

Slee Override or the Sensor Adjustment seem to be my two options. I'm only looking for a mild lift (1.5" or so) but would like to retain stock ride quality and maintain the lifespan of my AHC system. I definitely enjoy AHC and would like to keep it for a long time (my LX only has 54k miles), when it craps out I will move to a proven system like Icon. Of the two options does either reduce ride quality or lifespan of AHC. Which is the more proven, durable, safer option given I only want a 1.5" lift.
 
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Anyone have a measurement of stock ride height. I measured 28.5-30 from the lower lip of the wheel to the top of the wheel well. Just need a reference point

Thanks
 
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Hey there. New to the group. just got myself a 99 Lx470. Love her. This question may have been run ragged over the years but here goes... My question for this thing is; can you put aftermarket coils, shocks, and uca without deleting the ahc? For example.. the 2.5 medium load kit from old man emu. Can you put that on the rig and still run the ahc? If not.. why? Again. New to the lx family. Bare with me.
 
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