2009 LX 570 ACH Pump Not Working after picking up from Body Shop (1 Viewer)

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Hello Everyone. I've found this site very reliable and helpful over the past couple of years. Now I'm seeking advice on how to handle my situation regarding my 2009 LX 570.

I've lost power to the AHC pump 175 miles or 3 days after getting vehicle back.

Important notes regarding my vehicle: Average 300 plus miles a day for the past 2 years or 200,000 miles over the past two years. I've had one issue with the vehicle in all 11 years. Lexus LX 570 is a beast.

Notes about my issue:

-Rear-ended on the freeway in poor icy driving conditions 6 weeks ago whereby my vehicle sat dormant during 40 days to repair. Primary Impact Rear of vehicle sliding into wall.

-Last Monday, I finally was able to accept the vehicle after 42 days to repair. Driving home, I noticed a lot of looseness in the steering and the ACH check 4 wheel alert popped up.

-I removed one of the AHC fuses on the passenger side fuse box before a long trip home in order to protect the pump. Haven't been able to get the pump to work since.


I've driven this vehicle very hard over the past 2 years. It doesn't break. I contacted the insurance company that was paying for everything and I was advised they will cover the breakdown only if the mechanic will announce the accident played a role in this defect.

Whatever my issue may be, I know the accident resulting in my car sitting dormant would be the straw that broke the camels back. Are there not a hundred ways to articulate how an accident might have resulted in the straw that breaks the camels back?

Both the body shop and the lexus dealership have told me over the phone there is no correlation between this happenings and the accident. I just find this hard to believe.

Couldn't something that was about to break due to 285,000 miles become exacerbated by a major rear impact collision and gradually break during those 175 miles I drove after picking up the vehicle?
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Any thoughts?

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Solution
You're making solid progress! Hang in there as I think you're getting to the root of the issues. I believe there to be 2:

1) First thing I would do is address the firm items. A single broken height sensor/misadjusted sensor is enough to cause all the issues you've described. I wouldn't jump to conclusions that the AHC ECU is faulty as that's exceedingly rare. Replace the broken arm but also have them evaluate whether the potentiometer (arm angle sensor) has been damaged/bent, or anything else in the vicinity. They'll need to properly setup the calibration on the new arm/angle sensor for the system to work properly. This last calibration - there's very real potential for the tech...

TeCKis300

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Can you clarify what you mean by you lost power to the AHC pump? Any chance you have techstream to get the actual CEL/MIL codes?

I would check the AHC reservoir first (behind passenger rear tire well). Is there fluid in there? Plausible that the accident caused a lead in the system that allowed all the fluid to bleed out over the 175 miles?
 

grinchy

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Is it in L or N? I had that same error recently and it was a not quite seated connector back by the trailer wiring harness. Right rear near the body mount.
here’s a pic
The lower one is for the AHC pump and sensors.
Unplug and replug it.

the AHC dtc can Definitely be read in tech stream. Those will help a lot in determining what is up.
E8C08E0F-D35B-4CC4-8BE4-7545B7E9AC89.jpeg
 
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Yes, I say "lost power" because I never heard the pump working days after messing with the fuse. I performed that reservoir check and it showed the fluid at maximum capacity as the vehicle being in the "low" state. Ii learned to check this from previous threads from this forum.

I have tried 4 low position, waiting for lights, turning off and the restarting. That somehow did affect or change the way the vehicle handled, but it did not affect the height or activate the pump. Normally, the pump can be heard cycling through, but still nothing.

Coincidentally, my Escort Passport 9500, which is a direct wired Radar, stopped working right after the accident. I decided to try and trouble shoot problems, and while searching , I found this burnt out wire that runs vertically from rear of vehicle along side of the passenger floorboard...Underneath the silver lexus outer floor trim that aligns underneath the door.

I'm wondering if this blue cord might be the pumps power source.

I recognize there are so many possibilities here. But, since the pump reservoir is full and I never heard any kind of alarming sound from the pump like it was failing, I figured this had to be electrical.

Perhaps I should wait until I get the diagnostic back from Lexus to try and glean how this accident contributed to whatever has failed.

It's hard to believe I can go from 300 miles a day for a couple of years uninterrupted and now suddenly this happening so soon after the vehicle sat dormant while being repaired, and it not being a byproduct of the accident.

burnt cable.jpg
 
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Is it in L or N? I had that same error recently and it was a not quite seated connector back by the trailer wiring harness. Right rear near the body mount.
here’s a pic
The lower one is for the AHC pump and sensors.
Unplug and replug it.

the AHC dtc can Definitely be read in tech stream. Those will help a lot in determining what is up.
View attachment 2633981
I tried this...and it's in the "N" position when I turn it on. If I initiate the 4 low and kill the engine, restart, It starts to the N with the Arrow pointing up. However, no pump action. I can detect some variation when I begin driving immediately afterwards, but without the pump making any noise to indicate it's active.
When adjusting the control switch setting to high or low from that point, I lose the arrow from the center box, but the text does appear,. i.e High, Low, Normal.

If I stop and restart the engine after losing the arrow, the arrow remains lost upon restart even though it indicates it's switching to "normal." The only way I can get the the arrow in the box with the 4 low hack or whatever.
 

grinchy

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The dealer will pull the codes, the issue will likely be in the wiring or physical damage to a hardline. I’m sure like you that its a wiring issue from the accident or the repair. That is how mine was behaving when the connector was loose, I had N, it the height switch had no effect and no arrows. there isn’t too much wiring for the AHC, so it will hopefully not be a complicated fix.
 
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The dealer will pull the codes, the issue will likely be in the wiring or physical damage to a hardline. I’m sure like you that its a wiring issue from the accident or the repair. That is how mine was behaving when the connector was loose, I had N, it the height switch had no effect and no arrows. there isn’t too much wiring for the AHC, so it will hopefully not be a complicated fix.
Yeah, thank you. I read all your posts or threads rather. I've read just about everything on this matter. I just wish I was more technical and could perform these voltage test or resistance as attached. I found this I believe from this sight...maybe club lexus.

My hunch is with the mulitmeter being the best start. But, I bow to all of you folks that are way more knowledgeable. I just wish I hadn't touched anything as I'm now feeling complicit and reckless having possibly ruined my chances for recovery from insurance.

pic.jpg
 

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Joined
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Is it in L or N? I had that same error recently and it was a not quite seated connector back by the trailer wiring harness. Right rear near the body mount.
here’s a pic
The lower one is for the AHC pump and sensors.
Unplug and replug it.

the AHC dtc can Definitely be read in tech stream. Those will help a lot in determining what is up.
View attachment 2633981
Wait, the sensor I pulled was directly accessible from the little panel in the rear well. I don't think what I unplugged is the same as this at least from this visual.
I'll hop underneath and take a look tomorrow. Regardless, I'm going to be all over this again tomorrow. Hopefully I don't cause more problems than I've already got.
 

grinchy

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Wait, the sensor I pulled was directly accessible from the little panel in the rear well. I don't think what I unplugged is the same as this at least from this visual.
I'll hop underneath and take a look tomorrow. Regardless, I'm going to be all over this again tomorrow. Hopefully I don't cause more problems than I've already got.
For orientation those two large bolt heads are where the rear tow hook bolts. I have an aftermarket bumper so my frame rail may look different.

you just pulled a fuse, that is not something they can hold you liable for.
 

grinchy

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When the shop tells you the dtc that will certainly help us figure more closely what is going on.
Did the ahc work and you had arrows when you got the rig back?
And what do you mean by loose steering?
 
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@grinchy I reviewed your old posts and appears you have a great rig. You need a train horn from hornblasters.com.
That aside, yes, the AHC did work the day of receiving the vehicle and driving 135 miles of the 175 miles. Arrows yes.
Loose steering might best be described as the difference between how steering feels when in normal or low versus high high or just high.,
if you know what I mean.
 

grinchy

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You need a train horn from hornblasters.com.
I'll take that under advisement :)

Failure en-route? Hmm. There are several options from failed hardline (you'd have fluid), to what you suspect with pump prime, to an electrical issue (likely since you've found some smoked wires). We really need the DTC.

Definitely replug that specified connector, it might not have been well seated when they had the rear end apart. Inspect it for burn when you have it apart.
 
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@grinchy I reviewed your history
I'll take that under advisement :)

Failure en-route? Hmm. There are several options from failed hardline (you'd have fluid), to what you suspect with pump prime, to an electrical issue (likely since you've found some smoked wires). We really need the DTC.

Definitely replug that specified connector, it might not have been well seated when they had the rear end apart. Inspect it for burn when you have it apart.
You guys are great. Unplugged and plugged the sensor located above the tow hooks as advised and wha la.

So now I have arrows and a functional pump. However, upon test drive, any hard breaking or speeding through curved declivities prompts the AHC warning and I lose arrow and N remains static as pump doesn't engage.

Interesting observations:
1. about 3 minutes for the the arrows and pump to engage after resetting sensor via plugged/unplugging.
2. Driving in high causes the steering wheel to rotate 20 degrees to the right and vehicle to veer right.
3. Back to square one with no arrow and no pump action, after a minute, resets and arrow.
4. Perfunctory measure tire to paint at N
Lr 5.0 / Lf 5.5
Rr 4.75 / Rf 4.88
5. Apologies for the pics, but at H, it's bad
Distributing height and clearly left side is higher


So, little disclaimer in that I've had periodic AHC warnings when breaking hard, but it would pass and everything has been normal UNTIL THE ACCIDENT.

I'm betting this new info provides way more insight into what's happening.

How can I link this to the accident?
Anyone have a confident answer to this puzzle?

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grinchy

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My guess is that the connection can be improved, easiest is to pull that connection apart again and carefully and lightly emery paper the contacts. Then reassemble. You could try dialectic grease too, but I’d do it as separate actions. If that doesn’t fix it the wire is probably loose or broken somewhere in the run to the pump, you can just flex along the length to the pump and try to find the weakness, this might also wake it up.

glad there is some progress!
 
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My guess is that the connection can be improved, easiest is to pull that connection apart again and carefully and lightly emery paper the contacts. Then reassemble. You could try dialectic grease too, but I’d do it as separate actions. If that doesn’t fix it the wire is probably loose or broken somewhere in the run to the pump, you can just flex along the length to the pump and try to find the weakness, this might also wake it

My guess is that the connection can be improved, easiest is to pull that connection apart again and carefully and lightly emery paper the contacts. Then reassemble. You could try dialectic grease too, but I’d do it as separate actions. If that doesn’t fix it the wire is probably loose or broken somewhere in the run to the pump, you can just flex along the length to the pump and try to find the weakness, this might also wake it up.

glad there is some progress!
Thanks again. Im going to try both next...of course once ive obtained Emory paper and dialectic grease
 
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Just an update from tonight. Took an 80 mile round trip tonight after having done another plug/.unplug and allowing the vehicle to settle in Normal with up/down arrows like normal. I could sense better suspension/handling from the rear, which switched to a mild bumpiness versus harsh bumps as in my original depiction.

Before heading back, I decided to reset for the third time. Had pump activated and I began the return with the N and both arrows up and down like normal.

Ride had increased gradual decline operating in low despite the Control Unit and Display indicating [(N) know this because I entered my garage w/o having to adjust to Low. Small garage]

The closer I got to my house the greater the ride deteriorated. Became nauseous; the ride actually wore me down, exhausted me.

I am mechanically uninclined, which I admit. But, willing to share a completely uneducated guess: Passenger side globes are shot...they permit only fractions of the nitrogen necessary to support proper lift which dissipates gradually over time. Ride there not so bad, but back was nauseating and on the final mile of traversed 10k times, it was like riding a horse bouncing up and down to where I felt my lethargic man boobs bouncing up and down. it was rough.

Anyway, Skeptical about emory paper or anything else. I need the print out.

Question or poll: Is the body shop leery to help because it is obvious their reassembly might be the fault; not a byproduct of the accident gone uninspected?
 
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Just an update from tonight. Took an 80 mile round trip tonight after having done another plug/.unplug and allowing the vehicle to settle in Normal with up/down arrows like normal. I could sense better suspension/handling from the rear, which switched to a mild bumpiness versus harsh bumps as in my original depiction.

Before heading back, I decided to reset for the third time. Had pump activated and I began the return with the N and both arrows up and down like normal.

Ride had increased gradual decline operating in low despite the Control Unit and Display indicating [(N) know this because I entered my garage w/o having to adjust to Low. Small garage]

The closer I got to my house the greater the ride deteriorated. Became nauseous; the ride actually wore me down, exhausted me.

I am mechanically uninclined, which I admit. But, willing to share a completely uneducated guess: Passenger side globes are shot...they permit only fractions of the nitrogen necessary to support proper lift which dissipates gradually over time. Ride there not so bad, but back was nauseating and on the final mile of traversed 10k times, it was like riding a horse bouncing up and down to where I felt my lethargic man boobs bouncing up and down. it was rough.

Anyway, Skeptical about emory paper or anything else. I need the print out.

Question or poll: Is the body shop leery to help because it is obvious their reassembly might be the fault; not a byproduct of the accident gone uninspected?
And, now that I think about it, since the lexus dealership knows it had just been repaired, they too want nothing to deal with it because they don't' want the possibility of being stuck with an evaluation that points fingers at the body shop. Wonder if I should even go to that Lexus appointment.
 

grinchy

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If you have ‘good’ ride at any time it is probably not accumulators, though these could be replaced at this age and mileage.
Sounds to me like you’re losing pressure as the pump is intermittently getting power.

It may take a few days to track down the root cause.
Order a tech stream cable, we will need that. I recommend the vxdiag option.

It may be that there is a computer fault, if that’s the case it could be cost effective to just put in a normal suspension rather than replace the computer four accumulators and possibly the pump. With the accident it could be that enough stuff got messed up that repair will be difficult to find a single cause.

don’t know yet because we can’t tell what is wrong on the computer side.
 

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