Thought that a good thread with detailed tech info on how the LX and now the optional LC suspension works would be good info.
Explain how the LX suspension works
- Thread starter SWUtah
- Start date
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Input Signals
(1) Height control sensor signal
The vehicle height and the distance between the tire and body frame is detected, and is input to suspension control ECU TERMINALS SHFL, SHFR, SHRR.
(2) Fluid pressure sensor signal The hydraulic pressure is detected, and the signal is input to suspension control ECU TERMINAL PACC.
(3) Temperature sensor signal The fluid temperature is detected, and the signal is input to suspension control ECU TERMINAL TOIL.
(4) Height control SW signal Detects the changes in the target vehicle height, and the signal is input to suspension control ECU TERMINALS DNSW, UPSW.
Detects the changes in the vehicle height control, and the signal is input to uspension control ECU TERMINAL NSW.
(5) Differential lock detection SW signal Detects the differential lock, and the signal is input to suspension control ECU TERMINAL EXI.
(6) L detection SW signal Detects the transfer gear L, and the signal is input to suspension control ECU TERMINAL L4SW.
(7) Stop light SW signal Detects the brake signal, and the signal is input to suspension control ECU TERMINAL STP.
(8) Generator signal Detects whether the engine is running or not, and the signal is input to suspension control ECU TERMINAL REG.
(9) Door courtesy SW signal Detects whether the door is open or closed, and the signal is input to suspension control ECU TERMINAL DOOR.
(10) Steering sensor signal Detects the rotation number of the steering wheel, and the signal is input to suspension control ECU TERMINAL SS2+, SS2–.
(11) Wheel speed sensor signal Detects the wheel speed signal, and the signal is input to suspension control ECU TERMINAL FLO, FRO.
(12)Damping mode select SW signal Detects whether the damping force mode is selected or not, and the signal is input to suspension control ECU TERMINALS TSW1, TSW2.
(13) Intelligent tester communication signal The intelligent tester requirement signal is sent to suspension control ECU TERMINAL SIL. The suspension control ECU also sends back a signal to the intelligent tester.
2. Vehicle Height Adjustment Function
(1) Vehicle height adjustment by the SW
By operating the SW, the vehicle height can be adjusted to three heights, low, normal, and high.
(2) Automatic leveling function The vehicle height is maintained at a certain level when the load is within the specified load capacity.
(3) Vehicle speed detection function The height is adjusted automatically in response to the vehicle speed.
(4) Extra HI mode In L range with the height at HI mode, the height is raised 20 mm automatically, when the wheels are idling on a bumpy road surface.
(5) Vehicle height control SW When the vehicle height control SW is turned off, the vehicle height control functions could be inhibited.
Damping Force Control Function
(1) Bouncing control The front and rear wheels are independently controlled electronically, to ensure adequate damping force at all times, in response to the bumpy road surface.
(2) Harshness control The damping force is controlled not to increase when the road condition does not require damping force, to ensure smooth and comfortable riding.
(3) Unsprung vibration control When unsprung sympathetic vibration is detected, the damping force is controlled so that it does not decrease below a certain level, to prevent such vibration and converge it, to ensure road holding.
(4) Vehicle speed sensing control To ensure optimal balance of comfortable riding and road holding, the minimum damping force is increased as the vehicle speed increases.
(5) Anti–roll control When the driver makes a turn, the damping force is controlled electronically according to the condition, and slows down the vehicle rolling speed.
(6) Anti–dive control The vehicle dive condition is detected at an early stage through braking and the vehicle wheel speed signal, and the damping force is controlled according to the condition, to slow down the dive speed when decelerating.
(7) Anti–squat control The vehicle squat condition at acceleration is detected at an early stage, and the damping force is switched to a higher level to avoid squat.
(8) Damping mode select SW The damping mode select SW has 4 modes, and can be changed according to the driver preference.
4. Wheel Disconnection Function Usually the right and left wheels are connected, but when the driver turns the steering wheel, the wheels are disconnected in response to the condition. This is to prevent roll angle increase when making a turn.
(1) Height control sensor signal
The vehicle height and the distance between the tire and body frame is detected, and is input to suspension control ECU TERMINALS SHFL, SHFR, SHRR.
(2) Fluid pressure sensor signal The hydraulic pressure is detected, and the signal is input to suspension control ECU TERMINAL PACC.
(3) Temperature sensor signal The fluid temperature is detected, and the signal is input to suspension control ECU TERMINAL TOIL.
(4) Height control SW signal Detects the changes in the target vehicle height, and the signal is input to suspension control ECU TERMINALS DNSW, UPSW.
Detects the changes in the vehicle height control, and the signal is input to uspension control ECU TERMINAL NSW.
(5) Differential lock detection SW signal Detects the differential lock, and the signal is input to suspension control ECU TERMINAL EXI.
(6) L detection SW signal Detects the transfer gear L, and the signal is input to suspension control ECU TERMINAL L4SW.
(7) Stop light SW signal Detects the brake signal, and the signal is input to suspension control ECU TERMINAL STP.
(8) Generator signal Detects whether the engine is running or not, and the signal is input to suspension control ECU TERMINAL REG.
(9) Door courtesy SW signal Detects whether the door is open or closed, and the signal is input to suspension control ECU TERMINAL DOOR.
(10) Steering sensor signal Detects the rotation number of the steering wheel, and the signal is input to suspension control ECU TERMINAL SS2+, SS2–.
(11) Wheel speed sensor signal Detects the wheel speed signal, and the signal is input to suspension control ECU TERMINAL FLO, FRO.
(12)Damping mode select SW signal Detects whether the damping force mode is selected or not, and the signal is input to suspension control ECU TERMINALS TSW1, TSW2.
(13) Intelligent tester communication signal The intelligent tester requirement signal is sent to suspension control ECU TERMINAL SIL. The suspension control ECU also sends back a signal to the intelligent tester.
2. Vehicle Height Adjustment Function
(1) Vehicle height adjustment by the SW
By operating the SW, the vehicle height can be adjusted to three heights, low, normal, and high.
(2) Automatic leveling function The vehicle height is maintained at a certain level when the load is within the specified load capacity.
(3) Vehicle speed detection function The height is adjusted automatically in response to the vehicle speed.
(4) Extra HI mode In L range with the height at HI mode, the height is raised 20 mm automatically, when the wheels are idling on a bumpy road surface.
(5) Vehicle height control SW When the vehicle height control SW is turned off, the vehicle height control functions could be inhibited.
Damping Force Control Function
(1) Bouncing control The front and rear wheels are independently controlled electronically, to ensure adequate damping force at all times, in response to the bumpy road surface.
(2) Harshness control The damping force is controlled not to increase when the road condition does not require damping force, to ensure smooth and comfortable riding.
(3) Unsprung vibration control When unsprung sympathetic vibration is detected, the damping force is controlled so that it does not decrease below a certain level, to prevent such vibration and converge it, to ensure road holding.
(4) Vehicle speed sensing control To ensure optimal balance of comfortable riding and road holding, the minimum damping force is increased as the vehicle speed increases.
(5) Anti–roll control When the driver makes a turn, the damping force is controlled electronically according to the condition, and slows down the vehicle rolling speed.
(6) Anti–dive control The vehicle dive condition is detected at an early stage through braking and the vehicle wheel speed signal, and the damping force is controlled according to the condition, to slow down the dive speed when decelerating.
(7) Anti–squat control The vehicle squat condition at acceleration is detected at an early stage, and the damping force is switched to a higher level to avoid squat.
(8) Damping mode select SW The damping mode select SW has 4 modes, and can be changed according to the driver preference.
4. Wheel Disconnection Function Usually the right and left wheels are connected, but when the driver turns the steering wheel, the wheels are disconnected in response to the condition. This is to prevent roll angle increase when making a turn.
hoser
SILVER Star
Here's a good explanation of how Hydropneumatic suspension systems in general work.
Jim_Chow
V8_Fan
I second 100TD's response. It's exactly what the '03 LX AHC system outline says (100TD, did you type all that in from the FSM?). For the '03+, the FLO, FRO, SS2+, and SS2- inputs into the AHC ECU come from the VGRS ECU.
100 TD entry https://forum.ih8mud.com/showpost.php?p=1834890&postcount=2 is same as '99 LX FSM excerpt (Electrical Wiring Diagram FSM) with minor difference:
(10) Steering sensor signal Detects the rotation number of the steering wheel, and the signal is input to suspension control ECU TERMINAL SS1, SS2. (Not SS2+, SS2– as noted by 100 TD)
(However, this may have been changed by revisions to '99 LX FSM, I dunno.)
What I am curious about is whether Toyota changed the performance characteristics of the AHC/AVS systems for different years of 100 Series LX470/LC. For example: Was the anti-roll control increased (to reduce body roll in turns) for later years? Etc.
(10) Steering sensor signal Detects the rotation number of the steering wheel, and the signal is input to suspension control ECU TERMINAL SS1, SS2. (Not SS2+, SS2– as noted by 100 TD)
(However, this may have been changed by revisions to '99 LX FSM, I dunno.)
What I am curious about is whether Toyota changed the performance characteristics of the AHC/AVS systems for different years of 100 Series LX470/LC. For example: Was the anti-roll control increased (to reduce body roll in turns) for later years? Etc.
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Donald this is a cut from the manual, I expect what it says is what happens, the inputs don't show the accellaration/decelarition sensor or the yaw rate sensor, it appears that the wheel travel inputs from each AHC sensor are used to determine suspension travel at low speed and if they are being actively pushed the extra HI mode comes in. I don't have AHC so I haven't played with it and haven't worried about understanding it. (Too many other things to work on)
The new 200 series won't have AHC AFAIK, it will have the KDSS in the top line models, so a whole new ball game to play with.
