Help deciphering my AHC (1 Viewer)

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Joined
Apr 14, 2019
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5
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Location
Asheville, NC
Hey all. After getting Techstream set up I wanted to figure out the status of my AHC system. It is a 2006 LC with 198k. Very well maintained, little to no rust. My only issue since getting it has been a somewhat *heavy* suspension. Driving with the shocks set to comfort the ride is pretty nice but even in comfort mode I get more road feel than I would think I should be getting. Anyway, I hooked the LC up to Techstream and these were the results:

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Those tests were done going *up* from Low setting to High setting. I then went back down from High to Medium to see if that mattered and I got really high values after going from H to N. I waited a couple of minutes to see if the values would go down but they did not. I then went back to LOW and then back to NORMAL and the pressures then looked like the original settings in the first table above. (ie. 7.9 / 7.1 / 10.3)

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I also observed the ACH fluid levels in the reservoir and from LOW to HIGH it seems to dip 7-8 bars.

Anyone have any recommendations on how to massage the AHC to get a better ride and lower the pressures?

Thanks!
 
You have a bit of reading to do. It's all in here - no point in repeating the same things all over again, and again.
Read up on pressure reading. Then get pressures and heights in spec. Then check the accumulators' state.
 
You have a bit of reading to do. It's all in here - no point in repeating the same things all over again, and again.
Read up on pressure reading. Then get pressures and heights in spec. Then check the accumulators' state.

I have looked but I have seen no references to the weird behavior of significantly higher pressures being maintained when going from HIGH to NORMAL which seems like it could be an indicator of a component-level issue that would be simple to diagnose by a knowledgeable user who has wrestled with their own AHC.
 
You have a bit of reading to do. It's all in here - no point in repeating the same things all over again, and again.
Read up on pressure reading. Then get pressures and heights in spec. Then check the accumulators' state.
It’s like we’ve never posted anything about the system 🤷‍♂️
 
I have looked but I have seen no references to the weird behavior of significantly higher pressures being maintained when going from HIGH to NORMAL which seems like it could be an indicator of a component-level issue that would be simple to diagnose by a knowledgeable user who has wrestled with their own AHC.
The only pressure readings that matter are those read by the ECU on a L to N raise - H > N etc have absolutely no relevance. There is a single pressure transducer that monitors the pumps output pressure and captures values as the front, rear and height accumulator solenoids change their status from on to off during the raise cycle. There isn’t anything to decipher with spurious values displayed on H > N cycling because they have no relevance.
 
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Anyone have any recommendations on how to massage the AHC to get a better ride and lower the pressures?

You have a bit of reading to do. It's all in here - no point in repeating the same things all over again, and again.
Read up on pressure reading. Then get pressures and heights in spec. Then check the accumulators' state.

This is the place to start:

 

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