AHC trouble, bouncy rear end (1 Viewer)

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Jul 9, 2019
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I've got an '01 LX with about 230k. I've had it for about 2 years now, second owner, and the original maintenance history is impeccable. The AHC has worked as intended, until yesterday. We flushed the fluid last summer, because we weren't sure when it was last done. Last night I noticed that the rear end was super bouncy, even over the smallest bump. When I got home I tried cycling the system, and only the front end adjusts. In the light of day, I can see now that she's sitting super low in the rear. Fluid reservoir is full and there is no evidence of leaks. I've been searching the forum trying to get an idea of whether this might be a globe/accumulator issue or of it might just be a height sensor issue, but am coming up blank. We do not have a techstream. I do like the AHC, but if I'm going to spend $$$ repairing it, I'd almost rather just delete and spend the money on a small lift. Is there much if anything that we can figure out without a techstream?


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GTV

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Si'ahl
Nope. Techstream cable is about $30. It’s a small investment and it will do a whole lot more than just read your AHC pressures. Anything else is just guesswork.
 
Joined
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Nope. Techstream cable is about $30. It’s a small investment and it will do a whole lot more than just read your AHC pressures. Anything else is just guesswork.
As I suspected. For some reason I thought techstream was significantly more expensive and was pleasantly surprised when I started looking at them this morning.
 

suprarx7nut

The YotaMD Guy
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As I suspected. For some reason I thought techstream was significantly more expensive and was pleasantly surprised when I started looking at them this morning.
Yup, the hardest part of getting started with AHC work is setting up Techstream. Once you get over that hurdle, it's not too bad.

You're probably just over-pressure or have a bad height sensor. Techstream will likely reveal the answer in 30 seconds once you get it going.

Keep in mind that there are essentially no AHC failures that cost anywhere near as much as you might have heard. Insane/unethical/misguided dealer quotes have created a false impression that AHC is ungodly expensive to maintain or repair. It's a baseless idea when you consider current parts availability and community knowledge. Globes are a wear item and cost ~$750 every decade or so. New springs or spacers are a couple hundred at most. The shocks almost never require replacement. The pump is $250. Unless you have catastrophic rust that's ravaging your undercarriage, there's no normal failure of AHC that would be as expensive as even a cheap lift kit.

We can walk you through the journey. :)

Check out this if you haven't already.

 
Joined
Jul 9, 2019
Messages
16
Location
IL
Yup, the hardest part of getting started with AHC work is setting up Techstream. Once you get over that hurdle, it's not too bad.

You're probably just over-pressure or have a bad height sensor. Techstream will likely reveal the answer in 30 seconds once you get it going.

Keep in mind that there are essentially no AHC failures that cost anywhere near as much as you might have heard. Insane/unethical/misguided dealer quotes have created a false impression that AHC is ungodly expensive to maintain or repair. It's a baseless idea when you consider current parts availability and community knowledge. Globes are a wear item and cost ~$750 every decade or so. New springs or spacers are a couple hundred at most. The shocks almost never require replacement. The pump is $250. Unless you have catastrophic rust that's ravaging your undercarriage, there's no normal failure of AHC that would be as expensive as even a cheap lift kit.

We can walk you through the journey. :)

Check out this if you haven't already.

Awesome. Thanks for the link!
 
Joined
Apr 3, 2021
Messages
18
Location
Monterey
Hi guys. I hope you don't mind me jumping into this thread. I have a 98 470. 355K miles. I love this truck. Having problems with a really bouncy ride. I've flushed and replaced the fluid. Saw a lot of air in the fluid when doing that. Took a while to remove it. The new fluid didn't do anything - other than let me know it's not a fluid issue. I've never replaced anything on the AHC. I purchased a Techstream cable. It also came with a Techstream installation CD. Techstream appears to need dealer registration codes, etc. to properly install. I don't have any of that. Do you recommend I take the time to figure out how to get Techstream up and running or should I simply take the step to replace the globes as I'm sure they're at the end of their life or very close. ? Could really use your guidance. I'd like to keep the AHC as it's been so good for so long.
 
Joined
Apr 3, 2021
Messages
18
Location
Monterey
Hi guys. I hope you don't mind me jumping into this thread. I have a 98 470. 355K miles. I love this truck. Having problems with a really bouncy ride. I've flushed and replaced the fluid. Saw a lot of air in the fluid when doing that. Took a while to remove it. The new fluid didn't do anything - other than let me know it's not a fluid issue. I've never replaced anything on the AHC. I purchased a Techstream cable. It also came with a Techstream installation CD. Techstream appears to need dealer registration codes, etc. to properly install. I don't have any of that. Do you recommend I take the time to figure out how to get Techstream up and running or should I simply take the step to replace the globes as I'm sure they're at the end of their life or very close. ? Could really use your guidance. I'd like to keep the AHC as it's been so good for so long.
I fogot to mention that I only have 4-5 graduation levels change between high and low.
 
Joined
Jul 9, 2019
Messages
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Location
IL
Hi guys. I hope you don't mind me jumping into this thread. I have a 98 470. 355K miles. I love this truck. Having problems with a really bouncy ride. I've flushed and replaced the fluid. Saw a lot of air in the fluid when doing that. Took a while to remove it. The new fluid didn't do anything - other than let me know it's not a fluid issue. I've never replaced anything on the AHC. I purchased a Techstream cable. It also came with a Techstream installation CD. Techstream appears to need dealer registration codes, etc. to properly install. I don't have any of that. Do you recommend I take the time to figure out how to get Techstream up and running or should I simply take the step to replace the globes as I'm sure they're at the end of their life or very close. ? Could really use your guidance. I'd like to keep the AHC as it's been so good for so long.
I ordered a cable that came with a disc. It just came today and I started installing it on an old laptop. Buried in the files were instructions and the registration code was in there. Maybe check the text files on your disc.
 
Joined
Apr 3, 2021
Messages
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Location
Monterey
What is TS?
BTW - I should add that the system appears to move somewhat properly from L to N to H, although there is an odd knocking sound (hard to describe) coming from both the front left and front right when I go from L to N. No blinking lights on AHC indicator and vehicle raises/lowers in accordance with the AHC switch. However, there is still only a 4-5 graduation change
 
Joined
Jul 9, 2019
Messages
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IL
Update- sensors and accumulators are all in working order. The bracket that holds the rear height sensor in place broke and the sensor is just hanging. We figured this out after we got the techstream up and running and the rear sensor value was out of whack. The good news here, besides no catastrophic failure, is that I now have a techstream to make sure we get the sensor back in the right position and that my husband finally had an excuse to buy a welder.
 

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