Help - AHC problem while changing fluid (1 Viewer)

Joined
Jun 22, 2020
Messages
31
Location
SoCal
Any issues with that little filter that sits in the neck? Kink in any of the soft lines around the neck?
 

Snafu13F

SILVER Star
Joined
Aug 30, 2020
Messages
97
Location
Clarksville TN
So after removing the bumper and various panels to get to the pump, I decided to take it to a trusted local shop to get a professional diagnosis. If it turn out to be a bad pump, I’m going to have to drive it as is for a few months. The pump is crazy expensive! Fingers crossed, I’m still hoping it’s just a clog between the tank and the pump.
 

nwfl4runner

GOLD Star
Joined
Mar 11, 2018
Messages
401
Location
pensacola
Order the pump from partsouq (48910-60032) and it’s $1100 shipped - much better than state side. I’m betting pump is fine though
 
Joined
May 18, 2017
Messages
1,231
Location
Vernon, BC
Oh man... this brings up bad memories. C1763 makes another appearance :(

It is almost certainly air in the system. Also keep in mind that the AHC pump is NOT self priming and if you run it without fluid in it you WILL burn it out (as a local Lexus master tech recently found out... before blaming Lexus for "sending a bad bump").
 

radman

SILVER Star
Joined
May 28, 2019
Messages
1,109
Location
Houston
So after removing the bumper and various panels to get to the pump, I decided to take it to a trusted local shop to get a professional diagnosis. If it turn out to be a bad pump, I’m going to have to drive it as is for a few months. The pump is crazy expensive! Fingers crossed, I’m still hoping it’s just a clog between the tank and the pump.

You've got this... see if any of this helps you (i have more confidence in what you've done so far vs a mechanic that has never see ahc before)

1602101471121.png

1602101491623.png

1602101524739.png

1602101539059.png

1602101618409.png
 

radman

SILVER Star
Joined
May 28, 2019
Messages
1,109
Location
Houston
These images are from the C1763 error section (first page above). Not sure if relevant since you're hearing the pump run
1602101665845.png

1602101685177.png

1602101732441.png



Also keep in mind that the AHC pump is NOT self priming

I did a quick check, and didn't see anything about bench bleeding. 🤷‍♂️
 
Last edited:
Joined
May 18, 2017
Messages
1,231
Location
Vernon, BC
I did a quick check, and didn't see anything about bench bleeding. 🤷‍♂️

The "not self priming" is what I was told by another master Lexus mechanic - the one that ended up fixing my LX. He explicitly told me that the pump HAS to be primed manually, otherwise it will burn out, like what the first mechanic did.
 

Snafu13F

SILVER Star
Joined
Aug 30, 2020
Messages
97
Location
Clarksville TN
So I picked up the truck from the mechanic...who had no idea what was causing the problem. So I’ve brought it home and will re attack the problem myself in the morning.
the idea that the pump needs to be primed is promising. Does anyone know how I would go about this? I haven’t found anything in the repair manuals thus far.
I could simply drain the system and pull the pump for inspection, but I would end up having to reprime it after reinstalling anyway, so priming and testing seems the logical next move. I’m all ears on suggestions on this. I did a bit of reading on it and noted that pumps sometimes lose prime because of blockages in the inlet filter. Which sounds very plausible.

The mechanic rebled the system several times it appears. The front left tire is buried in the wheel well and it drove so badly on the way home I started feeling motion sickness. I will need to reintroduce fluid into the front collectors to remedy this. I’m assuming I’ll have to pump some in via the bleeders, which should be fun with only a manual pump. That’s my last gasp plan at the end of day Thursday. I need it driveable by then, or I will have to take a car on my weekend trip into the hills.

ps.Since I know more than a few of you have ripped out your ahc,(I think it’s a great system personally), does anyone have a functioning pump they would be willing to part with? PM me if you do!
 

Snafu13F

SILVER Star
Joined
Aug 30, 2020
Messages
97
Location
Clarksville TN
I read the very same article last night. It’s given me a few ideas that I’m going to try today.
 
Joined
Jun 3, 2013
Messages
352
Location
Las Vegas, NV
So I picked up the truck from the mechanic...who had no idea what was causing the problem. So I’ve brought it home and will re attack the problem myself in the morning.
the idea that the pump needs to be primed is promising. Does anyone know how I would go about this? I haven’t found anything in the repair manuals thus far.
I could simply drain the system and pull the pump for inspection, but I would end up having to reprime it after reinstalling anyway, so priming and testing seems the logical next move. I’m all ears on suggestions on this. I did a bit of reading on it and noted that pumps sometimes lose prime because of blockages in the inlet filter. Which sounds very plausible.

The mechanic rebled the system several times it appears. The front left tire is buried in the wheel well and it drove so badly on the way home I started feeling motion sickness. I will need to reintroduce fluid into the front collectors to remedy this. I’m assuming I’ll have to pump some in via the bleeders, which should be fun with only a manual pump. That’s my last gasp plan at the end of day Thursday. I need it driveable by then, or I will have to take a car on my weekend trip into the hills.

ps.Since I know more than a few of you have ripped out your ahc,(I think it’s a great system personally), does anyone have a functioning pump they would be willing to part with? PM me if you do!

My pump is still attached, I can remove it tonight after work. Any tips on removal?
 

Snafu13F

SILVER Star
Joined
Aug 30, 2020
Messages
97
Location
Clarksville TN
The "not self priming" is what I was told by another master Lexus mechanic - the one that ended up fixing my LX. He explicitly told me that the pump HAS to be primed manually, otherwise it will burn out, like what the first mechanic did.
Do you know the guys name? What dealership? I would love to talk to him. My first couple ideas today have had limited success.

My current plan is to start cracking hose fittings on the pump. This should theoretically allow any air in the pump to be replaced with oil. I’m going to mark my tank fluid level first, so I can see any fluid level changes.

Does anyone have fender measurements for the truck in low and normal modes? I just measured mine and got the following values. Truck is technically in low, but it’s actually below that I think.
FR 30 3/4
FL (passenger) 31
RR 32 1/8
RL (passenger) 32 3/4
 
Last edited:

Snafu13F

SILVER Star
Joined
Aug 30, 2020
Messages
97
Location
Clarksville TN
My pump is still attached, I can remove it tonight after work. Any tips on removal?

the manual shows removing both rear mud flaps, and the bumper cover. All easy, but don’t forget to unplug the rear sensors from the bumper. You also have to remove the luggage compartment cover protector 1 and the Fuel tank filler pipe protector. These were easy except for the 6 square plugs, which I had to cut to remove. I ordered a bag of replacements on amazon that should arrive today. 4 on the fuel cover, 2 on the luggage. I was able to get the luggage ones out.
You will need to discharge the fluid from the 5th accumulator to depressurization the system.
It all sounds more complicated than it is. Other than an hour wasted fighting the square plugs, it took less than an hour to remove all the pieces.

the annoying plugs in question:
B3ED3F6D-97A3-4B6B-8546-04D177D1470D.jpeg
 
Joined
May 18, 2017
Messages
1,231
Location
Vernon, BC
Do you know the guys name? What dealership? I would love to talk to him. My first couple ideas today have had limited success.

My current plan is to start cracking hose fittings on the pump. This should theoretically allow any air in the pump to be replaced with oil. I’m going to mark my tank fluid level first, so I can see any fluid level changes.

Does anyone have fender measurements for the truck in low and normal modes? I just measured mine and got the following values. Truck is technically in low, but it’s actually below that I think.
FR 30 3/4
FL (passenger) 31
RR 32 1/8
RL (passenger) 32 3/4

His name is Tyler; he runs an indy shop called "Certified Automotive" in West Kelowna, BC:

 
Last edited:
Joined
Jun 3, 2013
Messages
352
Location
Las Vegas, NV
the manual shows removing both rear mud flaps, and the bumper cover. All easy, but don’t forget to unplug the rear sensors from the bumper. You also have to remove the luggage compartment cover protector 1 and the Fuel tank filler pipe protector. These were easy except for the 6 square plugs, which I had to cut to remove. I ordered a bag of replacements on amazon that should arrive today. 4 on the fuel cover, 2 on the luggage. I was able to get the luggage ones out.
You will need to discharge the fluid from the 5th accumulator to depressurization the system.
It all sounds more complicated than it is. Other than an hour wasted fighting the square plugs, it took less than an hour to remove all the pieces.

the annoying plugs in question:
View attachment 2459376
I removed the pump, it has like 200k miles on it but was working fine before I disabled the system. There was still fluid in the reservoir, but I poured most of it out the fill tube. The strainer also fell into my used oil bucket.
 

Snafu13F

SILVER Star
Joined
Aug 30, 2020
Messages
97
Location
Clarksville TN
Tonight’s update: inexplicably, it works(I think).

I spent the entire day trying to get the pump to prime without luck. This evening, Tyler graciously called me back and made some suggestions. His solution: unhook the pump, turn the truck off and hook it directly to the battery, but reverse the poles at the connector. Running it in reverse is how he fixed @eatSleepWoof truck. So I jimmied up some wire clips, spare wire and jumper cables. Almost immediately, the cavitation stopped. I ran it for a few more seconds then reconnected the truck and started it up. Immediate cavitation again. I went back to running just the pump from the battery and the cavitation stopped. This time I let it run for a minute or two until my makeshift wire caught fire and damaged the connector. In a fit of rage, I went inside and ordered a pump.
An hour and two drinks later, I went back out and fixed the connector with a dremel and nothing to lose. I got the connector working and reconnected, wrapping it in waterproof tape. Then just for fun, I started to truck up...
and it immediately and quietly raised the entire truck back to N. I took it for a test drive and it seems fine. I won’t be attempting to raise or lower it until next week, when I have time and new fluid. I did bleed the accumulator a bit and had no air, so a good sign. Truck looks and feels good. Just for confirmation, here’s the techstream pull I just did. Doesn’t look too far off I hope.

56B8CED9-5956-4672-A0C3-F1F6D270CA89.jpeg
 

radman

SILVER Star
Joined
May 28, 2019
Messages
1,109
Location
Houston
YES! I had high hopes for you.... 🍻

i wouldnt worry about raising. The rig will constantly use the pump for leveling, drop if you go over 62mph, and adjust according to the comfort level you have selected. Go raise to high and do a little dance.

Your offsets look a bit odd. Your front driver's side is being held back by a -.6" offset.

Take some new measurements? Front right is passenger and front left is driver. I think you have them backwards in your measurements above.
 

Users who are viewing this thread

Top Bottom