Help - AHC problem while changing fluid (1 Viewer)

Snafu13F

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Today I’ve attempted to change the fluid in my 2011 LX. I pumped out the old fluid in the tank per the pdf I downloaded on here, and refilled to above the max line. While draining the first bleed point, I Inadvertently removed about 12oz of fluid from the first Bleed point (rh front). I then started the vehicle and attempted to raise to N. After about 30 seconds of hearing the pump run but no actual adjustment in vehicle height, it gave me a check 4 Wheel AHC error. Simply starting the truck and letting it run for a minute or two gives this error now. I do not have a tech stream and honestly have no idea how to proceed. Can anyone help me out?
 
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Snafu13F

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Not as far as I can tell. The pump has started making noises like it’s running empty, so I shut the truck off. Reservoir still reads above max, the fluid level in it doesn’t change even though the pump is on
 

nwfl4runner

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Try disconnecting the battery for 15 min and try again. Probably getting an abnormal oil pressure in the motor code. Drain another corner (a bit) and see if that gets it moving too
 

Snafu13F

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I tried that and got the same result. The pump makes a high pitch whine that increases in pitch, so I’ve shut off the ahc. I’m guessing that it’s cavitating. The reservoir is still completely full. I’m in trouble I think
 

nwfl4runner

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Try draining some fluid from the reservoir. Shouldn’t be anywhere near max as it has a good supply even when bleeding. With some air, try moving it into high. Try to do it right after you turn on so the error code doesn’t kick in.

I would also bleed other corners a bit as well (nothing extreme).
 

radman

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did you bleed in N mode or Lo? Does it look like the rig is currently in Low or is your right front dropped?

You should raise to N after topping off the reservoir. bleed a corner, start the rig (dont raise to Hi), then shut off and continue bleeding.


My guess is you have a C1763 error, which can be cleared with techstream




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I’m no AHC expert but it sounds like you might have let some air in the system. When I bled mine recently I always leave a little fluid in the bottom of my bleeding bottle (like the 1 man brake bleeder) just in case to keep any air from working it’s way back in after the fluid was drained out of each corner.
 

Snafu13F

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Truck is currently stuck in low. I’m going to wait for my techstream cable to arrive before investigating further. I’ve disabled ahc, it still throws a check ahc error when driving. The rear has been extremely slow to adjust since I bought it, which I was hoping was just an old fluid issue. One thing I noted when I bled it, the passenger rear had so much air in it that it looked like foam. Still trying to find the procedure to remove air from the system, which I’ve seen referenced, but can’t find
 

radman

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Still trying to find the procedure to remove air from the system, which I’ve seen referenced, but can’t find


I have it posted above. Are you looking for something else?

At this point, I would start over with the 5th accumulator, the driver front, pass front, then driver rear, pass rear. Then, use Techstream to erase the codes if you still have issues.
 

Snafu13F

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No, that’s the correct procedure, I was having a senior moment when I looked at it.
At this point, I’m starting to wonder if there’s either a blockage between the reservoir and pump or an issue with the pump itself. Hopefully I will be able to get techstream set up tonight and see some codes. In the mean time I’m gonna read through to procedures to pull and test the pump. I’m beyond screwed if it’s a failing pump. Fingers crossed
 

radman

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Pull the pump before you check Techstream?
That's a lot of work that may not be necessary.


Let me know if you need any real-time help with Techstream or the bleeding.
 

Snafu13F

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I’m not gonna pull it before I check techstream, I’m just familiarizing myself with it.
I will definitely hit you up if I have questions, hydraulics are outside my experience, and I’m not as computer savvy as I once was. I’m hoping to have this fixed before I drive to Texas on Friday.
 

nwfl4runner

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I’ve sucked it in before. Just more fluid and keep bleeding. First time I ever did it and didn’t realize you can’t see a thing without a light where the spare tire sits...
 

Snafu13F

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Techstream is working. I get the C1763 code. Clearing it and restarting the truck results in the pump running very loudly and then generating the same code. No change in vehicle height. I’ve run multiple active tests, including trying to raise the front and rear. The pump runs but no change in height. Suggestions?
 

nwfl4runner

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Turn car on w/techstream running, clear code, go to AHC and force a front right or left height test. With a cleared code it should force it to raise
 

radman

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yep, that's the elusive pump code....

Did you happen to re-bleed your corners? 5th accumulator?
 

Snafu13F

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I’ve re bled the corners and got no air. I haven’t been able to get the cover off to bleed the accumulator. Nothing happens when I perform the individual wheelup/down tests. When I do Front or rear up/down by accumulator, the pump runs. The back does not change, but the front test does raise slightly. The pump makes a high pitch noise in all events, which I am interpreting as a pump running without fluid in it. At this point, all I can think of is there is some sort of clog between the tank and the pump. Does anyone else have any ideas before I start pulling off the rear bumper cover?
 

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