87 Land Cruiser
GOLD Star
Thank you, it looked like it was an odd shape or had something extra going on.
Sensor lift (1 Viewer)
- Thread starter gamecock2009
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Thank you, it looked like it was an odd shape or had something extra going on.
It is a little differvent, but a 10mm works fine
I think that's a "external Torx" or an "E-Torx". I just bought a few of these for a job on a friends gx470. It's a pretty cool fastener. It allows for a VERY solid grip/purchase on the bolt head.
Amazon.com: Craftsman 9-34570 External Torx Socket Set with1/4 and 3/8-Inch Drive, 7-Piece: Home Improvement
Amazon.com: Craftsman 9-34570 External Torx Socket Set with1/4 and 3/8-Inch Drive, 7-Piece: Home Improvement
amzn.to
If a standard 10mm starts to slip or anything, I'd go grab a set of these at the hardware store. Sears and Home Depot carry them by me and of course, there's Amazon.
- Thread starter
- #45
Got tech stream up and running and had an error C1762 "abnormal pressure in pump" which I believe means theres air in the lines which might account for my front end being lower than usual. And here is a picture of my pressures... all which read 0. Any ideas?
- Thread starter
- #46
I have a 2000 LX that AHC seems to work fine, High and Low and I tow a boat often without an issues. The front end does seem to be a little lower than normal at about 18inches fender to center wheel and my mechanic believes one of the front shocks is leaking or seeping. Today I finally got tech stream installed and it showed C1762 "abnormal oil pressure for pump" and pressures of 0 across the board. There are a few threads discussing this and it seems to point to a bad pump/sensor or air in the lines. Honestly I dont know if the fluid has ever been changed by previous owner, should I start there? Hopefully PADOO can chime in.
trdcorolla
SILVER Star
Have you cleared the code and tried again? Also you need to change heights and go back to neutral before it'll show any pressure in techstream. Make sure you do this on level ground with the gas tank full..
- Thread starter
- #49
Ill go ahead and clear it. So i just need to go from N to H to back to N to see pressures... Damn ifeel dumb
- Thread starter
- #50
Here we go, finally got pressures....
Neutral:
Front: 8.4
Rear: 7.7
Accumulator: 10.5
High (if it matters)
Front: 11.0
Rear: 8.7
Accumulator: 10.6
So it looks like I need to do some cranking of my tbars and maybe throw in a rear spacer?
Neutral:
Front: 8.4
Rear: 7.7
Accumulator: 10.5
High (if it matters)
Front: 11.0
Rear: 8.7
Accumulator: 10.6
So it looks like I need to do some cranking of my tbars and maybe throw in a rear spacer?
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- Thread starter
- #51
Cleared it and got N pressures of 8.4 front and 7.7 rear. Guess ill need to do some cranking and maybe some spacers in the rear?
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trdcorolla
SILVER Star
Yup, start cranking. You can mark the bolt and base with white out or something so it's easier to see it turn. My rear show about 1.0 high in techstream unless I pulled the AHC temp sensor, it looks like most here don't have to do that, but pulling the temp sensor is the way the FSM shows for reading the rear. I replaced my rear springs and my pressure didn't really change, then added the spacers before finding out about disconnecting the temp sensor. 
Nice work getting Techstream running.
For reference, that code means the system tried to run and either no pressure was built up by the pump or pressure change during "delivery" (to accumulators, I think?) was nearly none. Checks if that comes back are (according to the FSM):
1. Fluid Level
2. Ensure the pump runs by listening for it or jumpering it directly to power.
3. Bleed air
4. Inspect AHC relay
5. Check wire harness
6. Check pressure sensor
Now to your pressures, Yes, crank the hell out of those front T-bars. it's around .2 Mpa per full turn and the target is 6.8 so you've got roughly 8 full turns to go. Maybe do 6, drive around the block and test again. See if the height in N comes back up. Should be over 19" fender to center of wheel (19.75 if I recall).
For the rear your target is 6.1. I'd add a spacer if you don't plan on a storage system, rear bumper or other heavy things in the back. If you plan on any of those, I'd get King springs. Even with the spacers there's a chance you'll need new springs, but the spacers should do more than new springs either way.
I've heard mixed things on the temp sensor, but the manual does say to unplug that during the test and I'm sure there's good reason.
For reference, that code means the system tried to run and either no pressure was built up by the pump or pressure change during "delivery" (to accumulators, I think?) was nearly none. Checks if that comes back are (according to the FSM):
1. Fluid Level
2. Ensure the pump runs by listening for it or jumpering it directly to power.
3. Bleed air
4. Inspect AHC relay
5. Check wire harness
6. Check pressure sensor
Now to your pressures, Yes, crank the hell out of those front T-bars. it's around .2 Mpa per full turn and the target is 6.8 so you've got roughly 8 full turns to go. Maybe do 6, drive around the block and test again. See if the height in N comes back up. Should be over 19" fender to center of wheel (19.75 if I recall).
For the rear your target is 6.1. I'd add a spacer if you don't plan on a storage system, rear bumper or other heavy things in the back. If you plan on any of those, I'd get King springs. Even with the spacers there's a chance you'll need new springs, but the spacers should do more than new springs either way.
I've heard mixed things on the temp sensor, but the manual does say to unplug that during the test and I'm sure there's good reason.
Not sure if this should be a new topic yet, I finally get my LX this weekend so I havent played with it in person yet
but
has anyone looked at the actual sensors that control the lift? are they simple potentiometers or something more complicated? my thought is that if theyre just simple pots it would be fairly easy to replace them with something that could be controlled remotely/in-cabin, either through dials or even something like a teensy or arduino
but
has anyone looked at the actual sensors that control the lift? are they simple potentiometers or something more complicated? my thought is that if theyre just simple pots it would be fairly easy to replace them with something that could be controlled remotely/in-cabin, either through dials or even something like a teensy or arduino
Search around and you'll find pics of the sensors opened up. If I recall correctly, they're a multi-traced swiping pot, basically. Not stupid simple, but surely something you could imitate if you were determined. But.... I don't think manipulating those really gets you anywhere. The system already allows height adjustment when it's practical and for the adjustments to really be helpful you'd want to also adjust torsion bars and rear spring rates. The AHC system has some pretty extreme adjustment from the factory. 4-5 inches of vertical movement is a lot.
thank you I will check this out.
my understanding from reading this thread is that you can alter the AHC mounting brackets to gain 'lift' - im proposing not having to modify the brackets at all - Im assuming that the modification of the bracket adjusts where the pot lands on its 'sweep' (for lack of a better phrase)
You sound electrically savvy, which I am not, based on your brainstorming. From what I gather you essentially want to be able to add an on-demand sensor lift (or drop) without any mechanical changes. I would say what you propose is certainly possible, perhaps unnecessarily complex, and would likely compromise one of the best parts of AHC - relative simplicity and reliability (though many would debate the "compromise" and the "best part" statements). But only you can answer if it's worth it in your rig. Search this forum for pics of the internals, I have seen many on here but can't find one currently. It's basically 3 contact springs and 3 metal sweeps that each spring moves along. No idea how they are wired together or what each sweep sends signals to. Here's an EWD of the AHC system though if that helps.
I could be barking up the wrong tree here but from this thread there is this in the instructions that also has an image
AHC Sensor Adjustment for Lift
Adjusting your AHC sensors are fairly easy :)banana: job). You'll need to furnish/fabricate a simple bracket extension which I'll cover in step 5. You'll also need one can of AHC fluid from Toyota $22/can. (part # 08886-01805). I have heard the exact fluid costs more if bought from Lexus. 1...
forum.ih8mud.com
Once done, reinstall the heim joint and adjust it so that the Height Control Sensor lever is as high as possible. Remount the wheels. You can readust the sensor through the wheel-well later. Make sure ALL adjustments are done while the vehicle is OFF for safety reasons!
showing that the way the ahc compensates/adjusts pressure/lift is by the link actuating the sensor level which is turn sweeps the pot and provides a reference signal to the ECM and that controls the pumps and valves etc
im thinking that if you made a harness that was in between the sensor itself and its harness you could offer three different modes to AHC adjustment
1. off - doesnt interfere
2. on - allows you to manually override the sensor imagine a couple dials in the cabin where you could individually adjust the fronts and the 'rear' heigh on demand
3. some form of auto mode - that would mimic physical modifications of the links/sensor bracket
the sensors are probably just 0-5v pots (maybe 0-12v) at most and would be easy to intercept/modify
I could be barking up the wrong tree here but from this thread there is this in the instructions that also has an image
AHC Sensor Adjustment for Lift
Adjusting your AHC sensors are fairly easy :)banana: job). You'll need to furnish/fabricate a simple bracket extension which I'll cover in step 5. You'll also need one can of AHC fluid from Toyota $22/can. (part # 08886-01805). I have heard the exact fluid costs more if bought from Lexus. 1...
showing that the way the ahc compensates/adjusts pressure/lift is by the link actuating the sensor level which is turn sweeps the pot and provides a reference signal to the ECM and that controls the pumps and valves etc
im thinking that if you made a harness that was in between the sensor itself and its harness you could offer three different modes to AHC adjustment
1. off - doesnt interfere
2. on - allows you to manually override the sensor imagine a couple dials in the cabin where you could individually adjust the fronts and the 'rear' heigh on demand
3. some form of auto mode - that would mimic physical modifications of the links/sensor bracket
the sensors are probably just 0-5v pots (maybe 0-12v) at most and would be easy to intercept/modify
I could be barking up the wrong tree here but from this thread there is this in the instructions that also has an image
AHC Sensor Adjustment for Lift
Adjusting your AHC sensors are fairly easy :)banana: job). You'll need to furnish/fabricate a simple bracket extension which I'll cover in step 5. You'll also need one can of AHC fluid from Toyota $22/can. (part # 08886-01805). I have heard the exact fluid costs more if bought from Lexus. 1...
showing that the way the ahc compensates/adjusts pressure/lift is by the link actuating the sensor level which is turn sweeps the pot and provides a reference signal to the ECM and that controls the pumps and valves etc
im thinking that if you made a harness that was in between the sensor itself and its harness you could offer three different modes to AHC adjustment
1. off - doesnt interfere
2. on - allows you to manually override the sensor imagine a couple dials in the cabin where you could individually adjust the fronts and the 'rear' heigh on demand
3. some form of auto mode - that would mimic physical modifications of the links/sensor bracket
the sensors are probably just 0-5v pots (maybe 0-12v) at most and would be easy to intercept/modify
Here are a few well illustrated threads which may be helpful ....
Definitive list of AHC maintenance items (this takes you to Page 31)
AHC, Actual Height, Pressures - LC100 (this takes you to a short thread)
AHC, Actual Height, Pressures - LC100 (part of the same short thread)
- Thread starter
- #60
I think this thread has evolved to more than just a sensor lift so I probably need to change the title haha. Well now I finally have about neutral (7.0) pressure up front and surprisingly rear and check out that height for the control sensor right at 0 haha. I cranked the left bar about 6.5 turns and the right about 6 to get where I needed to be. I also gained about an inch of height in the front so it looks better in my opinion. Thanks to everyones help and dont hesitate for anyone else to reach out if they have any questions.
