AHC Help messed up while doing testing (1 Viewer)

[y5359]

2006 LX ACH was working but something was off and ride was bouncy. I started by running tech stream. I got the data then went to the graduation test. I found YotaMD AHC cheet sheet and that was the next tests I was going to go through but after putting car in low system is now showing off and won’t go back up. Globes were supposedly Changed by prior owner 2 years ago along with the pump. I’ve read Abcs of AHC and started working my way through the AHC thread but haven’t found anything yet. Any help would be greatly appreciated.

 

[y5359]

2006 LX ACH was working but something was off and ride was bouncy. I started by running tech stream. I got the data then went to the graduation test. I found YotaMD AHC cheet sheet and that was the next tests I was going to go through but after putting car in low system is now showing off and won’t go back up. Globes were supposedly Changed by prior owner 2 years ago along with the pump. I’ve read Abcs of AHC and started working my way through the AHC thread but haven’t found anything yet. Any help would be greatly appreciated.

View attachment 3154872

View attachment 3154873

No codes were showing

 

[Africaster]

A quick test … drive forward (or reverse) at at least 25mph … she should automatically return to Middle setting … then you can take your time to investigate further knowing you can at least drive to work etc

 

[uHu]

Are your door switches working ok? and brake/stop light ok? What's with your low battery voltage?
If everything checks out ok and you have no pump action, you might have a faulty relay or fuse.

 

[y5359]

I was able to get it back on and into the neutral setting by going over 25. Thanks Africaster.


I visually checked the fuses and they looked good. Brake lights work, and battery gauge is on the other side and it was just below 14. The LX will drop for a couple seconds when I first turn it on and then go back up so I think the pump is working.

Next thing I was going to try was to go through YotaMDs cheat sheet.

 

[Rebus Knebus]

Check your owner’s manual. There’s some sequence of ignition switch position plus height control switch activation that lets you turn off the AHC. Maybe you did that unintentionally.

 

[y5359]

I plugged in techstream again to try to get some pressure readings and could not get the car to go back up from the Low setting. I ran all the active tests while in there and when I ran the main relay test that is when it is turning the AHC to off. Does this mean my main relay is bad?

I did the measure as found 2 times so far and my front left measurements were 19.25 and 18.75. Front right was 19.5 both times, rear right was 20 both times and rear right was 20.25 both times.

 

[2001LC]

Your OP screen shot show DOOR SW ON. Were all 6 doors closed during test with tech stream. NO, close doors.
Are all door SW working properly as uHu asked. No, correct.

YES:

Was AHC going into all heights without issue, before hooking in tech stream (TS). If so look at pins in TS cable, make sure none bent. YES bent, correct pins.

NO:

If pressure too high in system, it fails. To take pressure off AHC front, put more of vehicle weight on T-bars and rear springs. You could try below or just start by adjusting T-bars CW. I'd start with 4 CW LH since lower and 2 on RH T-bar,

Drive again to get to raise if need, keeping TS actively hooked in reading data. You may need to repeat if not starting in N or H with TS reading data. Record or have helper watch pressures, as you put in low and drive to get back in N. If pressure to high above target of 6.8Mpa -+0.5 front and 5.6-6.7Mpa rear, about 10 seconds after system back to N, system will fall to raise. In this event: start with CW (clock wise) turns of the left t-bar to cross level since your measurement of LH was lower than RH. This will reduce pressures. Once level in N, give each T-bar and added 2 CW. Be mindful of readings being a bit higher, than doing a static test or anyone in vehicle. If it will not go back into N, while driving. Try CW turns anyway. Also be mindful, it is very hard to do CW in N or L. Having in H makes easier to CW turn T-bars. If can't get into H, raise front end with a jack if needed. The more weight T-bars carry, the hard to CW turn.

You were getting 18.75 than 19.25 on LH. Could be in the way your measuring. I place mark on grease cap in center. Than measure straight down from same point of fender. Mark on fender may help. All tires pressure needs to set to spec also. Full tank of gas. Or add buckets of water place over gas tank area.

If pressure not to high on AHC system. You may have a bad sensor a short or both. In this case I would except to see a trouble code.

Here a normal working AHC sample screen shot, after a bad globe replaced, AHC flushed and adj

 

[y5359]

I was able to get the cross level to match up at 19 3/8 after I did a short drive I measured again and they were 19.75 on both fronts. I had to put a lot of turns on the driver side to get it level. Is that a problem? I only have a couple threads on the drivers side and much more on the other.

 

[Africaster]

I had really similar symptoms to you, ended up replacing the up/down switch after many many rabbit holes and frustration … boom … everything started working as per manual

 

[suprarx7nut]

I was able to get the cross level to match up at 19 3/8 after I did a short drive I measured again and they were 19.75 on both fronts. I had to put a lot of turns on the driver side to get it level. Is that a problem? I only have a couple threads on the drivers side and much more on the other.

View attachment 3156528

View attachment 3156529

You need to measure pressures before you spend much effort adjusting cross level. You may need to lower both sides 10 turns (unlikely, but possible if you're maxing out threads). Or reindex up a tooth the other direction. All depends on pressure readings. Get us a screenshot of the system with that door switch OFF and let's see if anything else pops up.

 

[y5359]

You need to measure pressures before you spend much effort adjusting cross level. You may need to lower both sides 10 turns (unlikely, but possible if you're maxing out threads). Or reindex up a tooth the other direction. All depends on pressure readings. Get us a screenshot of the system with that door switch OFF and let's see if anything else pops up.

Thanks everyone for the help. Here is a screenshot with door switch off and I was able to get a pressure reading today.

 

[J1000]

Front pressure still too high. Adjust T-bars until pressure is 6.9. adjust both bars equally. It's easier to use a socket on an impact vs. a wrench. Put a piece of tape so you can count the rotations. Put anti-seize on the adjuster threads.

 

[y5359]

I'm having a really hard time getting it dialed in to 6.9. The last two times I tightened the t-bars I averaged .1 and the next time it was .33. Is their a problem with my sensor if I'm not getting the .2 per turn?

 

[J1000]

I'm having a really hard time getting it dialed in to 6.9. The last two times I tightened the t-bars I averaged .1 and the next time it was .33. Is their a problem with my sensor if I'm not getting the .2 per turn?

I would turn it 6-7 times then back the truck down the driveway and back up to settle the suspension. Suspension needs to move in order to settle at the new torsion.

 

[2001LC]

Last time I had one where pressure would not stay stable and system worked then would fail (OFF). Some cranks on T-bar had very small effect others big change. Where I had run out of T-bar adjuster threads on DS. It had bad sensors, where arms froze up and damaged sensors. That was the easy parts to fix. Other issue was much more difficult to isolate. It was a short, which I found in rear LH 1/4 wire hardness block.

 

[y5359]

I got the pressure pretty close. Not driving it for long enough to settle the suspension out cost me a lot of time. My drivers side TB is bottomed out to keep it level and get me there.

 

[2001LC]

If you've front sensor lift, you may max out the T-bar adjuster. If sensor at factory set point, you've issue. Possible short!

 

[y5359]

I’ll have to check the sensors. I wanted to run a few more pressure checks before I moved on to them. I ran two more checks this morning and got a couple of really low readings. Once in the front and once in the rear. Car is driving much better and pogo is pretty much gone now. Does this mean the sensors are going bad?

 

[2001LC]

Not necessarily, but may.

Check each sensor arm, to make sure has not loosened in slide.

Plug temp sensor back in. Run a few more test. Take to H, than L, than N and wait ~30 seconds for pressure reads to settle in. Do this about five times. Make sure on level ground, full tank of gas, no one in vehicle, no extra load in vehicle. Temp should go higher with each cycle. When system well balance, I do not see much Mpa change with temp sensor plugged in. What Mpa change I do see is more so in rear than front.