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Toyota Sequoia load leveling air suspension

I have a new toyota sequoia with rear load leveling air suspension. What concerns me is that the passengers side is higher than the other, pass. is 1/4 and sometimes 3/4 of an inch higher, is this normal. Please help.

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  • paranoid2 Oct 21, 2008

    The load leveling suspension has only been tried while stationary, it has a lift button which raises it 1.5 inches and lowering button which lower 1.5 inches. This feature was really not needed but the price of the limited without this fearture and the price for the platinum were the same. Since this vehicle is brand new and its only passengers are my 40 pound son and I who am 180 pounds; have been told to put some load in order to activate/calibrate its system. Sequoia has only 500 miles. Hate to have an inexperienced toyota tech. fiddling with my baby since its a new system.

  • Toyota Ed May 11, 2010

    Question: Are you manipulating the leveling suspension whilst driving? If so, you may be contributing to the issue; the leveler system is designed to be operated while stationary.

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6 Suggested Answers

  • 1861 Answers

SOURCE: 20080 sequoia platinum edition with load leveling issue

I think that you need a recalibration of the ride height sensors. Unfortunatly, this can only be done with a tool that the Toyota dealership has in the shop. I just did a Landcruiser with the same suspension, and it took me a while, could NOT get it right, I ended up having to replace one of the height sensors, but there were NO DTC codes in the suspension ECU. You either need a recalibration, or a sensor replacement, followed by a recalibration. I know this may not help you "do it yourself", but, this is what you need. A FixYa rating would be greatly appreciated. Hope I helped you out. Sorry about the sweating in TX. Nice here in PA.

Posted on Nov 06, 2008

  • 1 Answer

SOURCE: how to reset 2006 toyota sequoia after change oil

Previous Post dead wrong...

Turn ignition to "ON" position. Make sure odometer is on trip setting not on total vehicle mileage setting.

Turn ignition OFF

Push and hold odometer button while turning ignition to "ON" position. HOld for about 4-5 seconds until maintenance light goes off. Turn ignition OFF. Start up vehicle. There should be no more maintanence light.

Posted on Jun 27, 2009

  • 154 Answers

SOURCE: toyota sequoia trunk locked

remove back panel. be careful not to braek it and you can move the lock with a screwdriver tounlock it

Posted on Aug 17, 2009

  • 1986 Answers

SOURCE: want to fix the passenger side mirrow motor for

You'll need to remove screws that are by the door handle, arm rest, under door and side of door and then gently pull back on the panel as there will also be retaining clips attached and you don't want to break them. You'll need to lift the door panel upwards in order to get it off the window ledge. Then you can remove the bolts holding the mirror onto the door and disconnect the cables from the mirror going into the door

Posted on Sep 03, 2009

  • 1348 Answers

SOURCE: DIAGRAM FOR 2002 TOYOTA SEQUOIA STARTER REMOVAL

the big red cable from the battery goes right to it.

Posted on Sep 09, 2009

  • 6 Answers

SOURCE: reset the service indicator light - 06 Toyota Sequoia

set the mileage when the odometer is showing. put the key to off position. press and hold the reset button then turn the key to on position, do not start. then continue holding the reset button until the reading stops to zero or blank. turn it off, that should reset the light indicator

Posted on Feb 21, 2010

Testimonial: "thanks for the help! it worked like a charm. appreciate it! "

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3 Answers

When my envoy sits overnight my rearend drops down


There has been a service bulletin for that type of concern. Here is what it states.









Suspension - Rear Suspension Is Low/Sagging/Uneven

Notes




ENGINEERING INFORMATION

Bulletin No.: 06-03-09-006B

Date: December 15, 2008
Subject:
EI06006 - Rear Suspension Uneven, Sagging, Low (Recalibrate Air Spring Sensor)

Models:
2006-2007 Buick Rainier
2006-2007 Chevrolet TrailBlazer SS
2006-2007 GMC Envoy, Envoy XL
2006-2007 Saab 9-7X


with Suspension Pkg - Rear Load Leveling (RPO G67)

Supercede:

This bulletin is being revised to update the labor operation in the warranty information. Please discard Corporate Bulletin Number 06-03-09-006A (Section 03 - Suspension).

Condition

Some customers may comment on the rear suspension being uneven or sagging.

Correction

DO NOT REPLACE THE COMPRESSOR.

Based on technician feedback, engineering has determined that the customer's concern can be corrected by recalibrating the air spring sensor. Refer to the Trim Height Uneven or Low diagnostics and Air Spring Sensor Calibration procedure found in SI.

Nov 29, 2011 | 2004 GMC Envoy

1 Answer

2000 navigator: sit higher on one side than the other. replaced both air springs, front air struts, compressor, levelers, compressor relay. now the passenger side sits about two inchs higher than the...


make sure you don't have an air leak at the springs or the compressor. but you may want to have the air suspension module checked for fault codes. the module itself may be the issue not processing the inputs correctly and mis-leveling the vehicle.

Aug 03, 2011 | 2000 Lincoln Navigator

2 Answers

Front air suspension stopped working on my 2004 lincoln navigator. i replace the relay still doent work. Is there someway to reset the system


Vehicle Dynamic Suspension The four wheel air suspension system is comprised of the following components:
  • service switch
  • control module
  • two front height sensors
  • one rear height sensor
  • compressor and drier assembly (includes vent solenoid)
  • air lines
  • front and rear air spring and shock absorber assemblies
  • four air spring solenoids
-----------------------------------------------------------
Visual Inspection Chart Mechanical Electrical
  • Restricted suspension movement
  • Excessive vehicle load
  • Cut, severed, crimped air line(s)
  • Unmounted height sensor(s)
  • Damaged front air spring(s)
  • Damaged rear air spring(s)
  • Battery junction box (BJB) fuses 20 (30A), fuse 27 (5A), and fuse 111 (50A)
  • Loose, corroded, or disconnected connectors
  • Air suspension service switch is in the OFF position
  • Damaged solenoid valve(s)

  1. If the inspection reveals an obvious concern that can be readily repaired, correct the concern before continuing with Inspection and Verification.
  1. If the concern remains after the inspection, use the scan tool connected to the data link connector (DLC) to retrieve continuous diagnostic trouble codes (DTCs) and to execute On-Demand Self-Test diagnostics for the 4WAS module.
    • If the On-Demand Self-Test is passed and no DTCs are retrieved, GO to Symptom Chart to continue diagnostics.
    • If DTCs are retrieved, go to the 4WAS Module Diagnostic Trouble Code (DTC) Index in this section.
    • If the 4WAS module cannot be accessed by the scan tool, Go To Pinpoint Test A .
------------------------------------------

Aug 05, 2010 | 2004 Lincoln Navigator

1 Answer

1999 Towncar - Air suspension shocks in good condition and car rides level - no idicator light is on. The car just rides way too stiff. Even the slightest bump jolts the inside (rattles change in ash...


I will check the shop manual, but the module does control ride for stiffness, increased stiffness at higher speeds, etc. If the bags are inflated, then the module cintrols how much air to allow in or out based on inputs to the module. See if you can get one from a salvage yard form a cash for clunkers car.

A dealer can run a test for fault codes in the computer. Call and ask how much for just a scan for fault codes in the air suspension module.

-----------------------------
Vehicle Dynamic Suspension The vehicle dynamic suspension consists of the following components:
  • Rear air suspension control (RAS) module (5A919)
  • Snorkel
  • Drier
  • Air compressor (5319)
  • Air suspension switch (5K761)
  • Solenoid valve (5311)
  • Air spring (5560)
  • Air suspension height sensor (5359)
  • Air line
----------------------------------------------------------------------------
Rear Air Suspension Control Module
A microprocessor controls the air suspension system. The microprocessor and its supporting hardware are contained in the rear air suspension control module. The rear air suspension control module responds to signals from various sensors in the vehicle to maintain the programmed ride height while the vehicle is either moving or stopped. The rear air suspension control module accomplishes this by opening and closing solenoid valves to control the amount of air in the air spring(s). The rear air suspension control module turns on the compressor by applying voltage through the compressor relay to inflate the air spring(s) and raise the vehicle. The rear air suspension control module opens the vent solenoid to lower the vehicle by releasing air from the air spring(s) in response to signal inputs from the air suspension height sensor(s).
Air Suspension Switch
sxg~us~en~file=ani_caut.gif~gen~ref.gif CAUTION: The air suspension switch must be turned to the OFF position when the vehicle is hoisted, jacked, towed, jump started, or raised off the ground, to avoid unnecessary operation of the system and possible damage to the air suspension system components.
The air suspension switch provides a signal to the rear air suspension control module in the ON position to activate the system to maintain the programmed vehicle height.
Air Compressor
NOTE: The compressor contains a thermal overload circuit breaker. The circuit breaker automatically resets after a cool down period and after being tripped by excessive compressor motor heat.
The air compressor assembly consists of the compressor pump, electric motor and vent solenoid (must be installed as an assembly).
Air Suspension Height Sensor
The air suspension height sensor sends signals to the air suspension control module. There are three possible conditions that the air suspension control module interprets from the signals of the air suspension height sensors. The conditions are trim height, below trim height, or above trim height.
Solenoid Valve, Air Spring
sxg~us~en~file=ani_caut.gif~gen~ref.gif WARNING: Never rotate an air spring solenoid valve to the release slot in the air spring end cap fitting until all pressurized air has escaped from the air spring to prevent vehicle damage or personal injury.
The air spring solenoid valve allows air to enter and exit the rear air springs during height adjustment operations. The air spring solenoid valve is electrically operated and controlled by the air suspension control module.
Steering Sensor
The steering sensor provides the steering rate and position to the air suspension control module to avoid overcompensation of the air suspension during turns.
Inspection and Verification
  1. Verify the customer concern.
  1. NOTE: If the door ajar indicator is illuminated, repair the door ajar indicator. For additional information, refer to Section 413-09 .
    Visually inspect for obvious signs of mechanical and electrical damage.


Visual Inspection Chart Mechanical Electrical
  • Restricted suspension movement
  • Excessive vehicle load
  • Cut, severed or crimped air line(s)
  • Incorrectly mounted, damaged or disconnected height sensor
  • Damaged air spring(s)
  • Central junction box (CJB) Fuse:
    • 8 (10A)
    • 17 (10A)
  • Battery junction box (BJB) Fuse 12 (30A)
  • Loose or corroded connectors
  • Air suspension switch
  • Damaged air spring solenoid(s)


  1. If the concern remains after the inspection, connect New Generation STAR (NGS) Tester to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the NGS Tester menu. If NGS Tester does not communicate with the vehicle:
    • check that the program card is properly installed.
    • check the connections to the vehicle.
    • check the ignition switch position.
  1. If the NGS still does not communicate with the vehicle, refer to the New Generation STAR Tester manual.
  1. Carry out the DATA LINK DIAGNOSTIC TEST. If NGS Tester responds with:
    • CKT914, CKT915 or CKT70 = ALL ECUS NO RESP/NOT EQUIP. Refer to Section 418-00 .
    • NO RESP/NOT EQUIP for rear air suspension control module, go to Pinpoint Test A.
    • SYSTEM PASSED, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and perform self-test diagnostics for the rear air suspension control module.
  1. If the DTCs retrieved are related to the concern, go to Rear Air Suspension Control Module Diagnostic Trouble Code (DTC) Index to continue diagnostics.
  1. If no DTCs related to the concern are retrieved, proceed to Symptom Chart to continue diagnostics.
Rear Air Suspension Control Module Diagnostic Trouble Code (DTC) Index
NOTE: If rear air suspension control module C251 is disconnected before rear air suspension control module C250, DTCs C1830, C1770, C1790 and C1795 will be retrieved and must be cleared before an accurate list of continuous DTCs can be retrieved. The DTCs C1441 and C1442 will only be retrieved when running the electronic variable orifice (EVO) functional test on NGS Tester. The DTC C1897 will only be retrieved once per ignition switch cycle.

-----------------------------------------------------------------------------------
Module —Air Suspension Control Removal
sxg~us~en~file=ani_caut.gif~gen~ref.gif WARNING: Before performing maintenance on any air suspension components, disconnect the power to the system by turning off the air suspension switch located on the LH side of the luggage compartment to prevent vehicle damage or personal injury.
sxg~us~en~file=ani_caut.gif~gen~ref.gif CAUTION: Electronic modules are sensitive to static electrical charges. If exposed to these charges, damage may result.
  1. Turn the air suspension switch off.
  1. Disconnect the battery ground cable (14301).
  1. Pull out the lower instrument panel insulator.
    1. Remove the pushpins.
    1. Pull out the lower instrument panel insulator.
  1. Remove the lower instrument panel insulator.
    1. Disconnect the power point.
    1. Disconnect the courtesy lamp.
    1. Remove the lower instrument panel insulator.
  1. Remove the rear air suspension control module.
    1. Remove the screws.
    1. Disconnect the electrical connectors.
    1. Remove the rear air suspension control module.
Installation
  1. NOTE: When the battery is disconnected and reconnected, some abnormal drive symptoms may occur while the vehicle relearns its adaptive strategy. The vehicle may need to be driven 16 km (10 mi) or more to relearn the strategy.
    To install, reverse the removal procedure.

Jan 20, 2010 | Lincoln Town Car Cars & Trucks

3 Answers

The rear suspension air bags no work


start here

The air suspension system is designed to improve ride, handling and general vehicle performance for static, on-road and off-road driving condition:
  • Ride is improved by using an air type spring (the soft ride is inherent).
  • Handling is improved by maintaining constant vehicle attitude.
The system consists of unique rear air springs, air compressor, air lines, air spring solenoids, height sensor, air suspension control module, attachments and associated signals derived from both driver and road inputs. With these components and signals, the air suspension control module commands changes in vehicle height that are necessary for the load leveling features.
The load leveling feature rear air suspension (RAS) systems shall automatically make adjustments in vehicle height so that the vehicle is always at trim height and constant front-to-rear vehicle attitudes are maintained over the expected load range of the vehicle. Adjustments in height that are necessary to correct height differences between the vehicle's left and right sides for RAS system shall be restricted to what can be reliably achieved with one air suspension height sensor.
The system uses one air suspension height sensor, a steering sensor, generic electronic module (GEM) transfer case inputs, and other vehicle sensors to measure driver and road inputs. The system changes vehicle height using an air compressor, two air lines, and the use of an air spring with an air spring solenoid.
The air suspension system holds vehicle height when the rear hatch or any door is opened. The system stores rear vehicle height the moment any open door is detected. The system then maintains this height regardless of the addition or removal of a load. The system will return to its commanded height when all doors are closed and the vehicle speed exceeds 16 km/h (10 mph).
Air Suspension Switch
The air suspension switch is located behind the RH kick panel on a mounting bracket. The switch interrupts power to the air suspension control module.
The air suspension switch supplies a signal to the air suspension control module. Without the air suspension control module receiving this signal the load leveling system is inoperative and will not react when rear of the vehicle is raised or lowered. If the air suspension system is disabled by turning off air suspension switch, a "CHECK SUSP" will appear in the RH corner of the instrument cluster with the ignition in the run position.
Air Compressor
The RAS air compressor:
  • Is not interchangeable with four wheel air suspension (4WAS) compressor.
  • Consists of the compressor and vent solenoid; neither are replaceable as individual items.
  • Is mounted in the engine compartment between the washer fluid bottle and headlamp (RH front corner).
  • Is a single cylinder electric motor driven unit that provides pressurized air as required.
  • Is powered by a solid state relay, controlled by the air suspension control module.
  • Passes pressurized air through the compressor air drier that contains silica gel (a drying agent). Moisture is then removed from the compressor air drier when vented air passes out of the system during vent operation.
  • Air drier has a single port and is not interchangeable with 4WAS compressor air drier.
  • Air drier may be replaced separately.
  • Incorporates a snorkle that may be replaced separately.
The vent solenoid:
  • Allows air to escape from the system during venting actions.
  • Is located in the air compressor cylinder head.
  • Has a 160 psi internal relief valve.
  • Shares a common electrical connector with the air compressor motor.
  • Is enclosed in the cylinder head casting, which forms an integral valve housing that allows the valve tip to enter the pressurized side of the system.
  • Has an O-ring seal that prevents air leakage past the valve tip.
  • Opens when the air suspension control module determines lowering is required.
  • Provides an escape route for pressurized air that opens when system pressures exceed safe operating levels.
  • Is replaced with the air compressor as a unit.
Air Spring
RAS vehicles use air springs in the rear. The air springs provide a varying spring rate proportional to the systems air pressure and volume. The air suspension system regulates the air pressure in each air spring by compressing and venting the system air. Increasing air pressure (compressing) raises the rear of the vehicle while decreasing air pressure (venting) lowers the rear of the vehicle. Vehicle height is maintained by the addition and removal of air in each air spring through an air spring solenoid installed in the upper spring cap and energized through the air suspension control module.
The air springs are mounted between the axle spring seats and the frame upper spring seats.
The two air springs replace the conventional rear coil springs.
Air Suspension Height Sensor
When the air suspension height sensor indicates that the rear of the vehicle is lower than trim under normal driving conditions, the air compressor will turn on and pump compressed air to the air springs. When the sensor indicates that the rear of the vehicle is raised above trim under normal driving conditions, this will cause the air to be vented from the air springs to lower the vehicle back to its trim height level.
One air suspension height sensor is mounted on the vehicle. The air suspension height sensor sends a voltage signal to the air suspension control module. The output ranges from approximately 4.75 volts at minimum height (when the vehicle is low or in full jounce), to 0.25 volts at maximum height (when the vehicle is high or in full rebound). The air suspension height sensor has a useable range of 80 mm (3 in) compared to total suspension travel of 200-250 mm (8 to 10 in) at the wheel. Therefore, the air suspension height sensor is mounted to the suspension at a point where full rear suspension travel at the wheel is relative to 80 mm of travel at the air suspension height sensor. The air suspension height sensor is attached between the No. 5 frame crossmember (upper socket) and the panhard rod (lower socket). Replace the air suspension height sensor as a unit.
Compressor Relay
The compressor relay is energized by the air suspension control module to allow high current to flow from the battery to the compressor motor.
  • A solid state relay is used in the air suspension system for air compressor control. The relay incorporates a custom power metal oxide semi-conductor field effect transistor (MOSFET) and ceramic hybrid circuitry. The relay switches high current loads in response to low power signals and is controlled by the logic of the air suspension control module.
Air Suspension Control Module
NOTE: The 4WAS air suspension control module is used for the RAS system. The internal processor recognizes external circuitry to determine if it is installed in a 4WAS or a RAS equipped vehicle.
NOTE: The air suspension control module is calibrated with information from the air suspension height sensor. A new or exchanged air suspension control module requires a ride height adjustment calibration process to be performed.
The air suspension control module controls the air compressor motor (through a solid state relay), and the air spring solenoids. The air suspension control module also provides power to the air suspension height sensor. The air suspension control module controls vehicle height adjustments by monitoring the air suspension height sensor, vehicle speed, a steering sensor, acceleration input, the door ajar signal, transfer case signals, and the brake pedal position (BPP) switch. The air suspension control module also conducts all fail-safe and diagnostic strategies and contains self-test and communication software for testing of the vehicle and related components.
The air suspension control module is mounted in the passenger compartment inside the instrument panel above the radio and temperature controls.
The air suspension control module monitors and controls the air suspension system through a 32-pin two-way connector. The air suspension control module is keyed so that the air suspension control module cannot be plugged into an incorrect harness. There are two sides of the harness connection to the air suspension control module. Each is uniquely colored and keyed to prevent reversing the connections.
Air Suspension Diagnostic Connector
The air suspension diagnostic connector is used to aid the technician in diagnosing the air suspension system. It is also used to vent the system of compressed air when air suspension system components need to be repaired or replaced. The air suspension diagnostic connector is located under steering column.

Oct 02, 2009 | 1998 Ford Expedition

2 Answers

99 expedition two wheel drive passenger side goes up higher than the drivers side.uneven ride! whats a ride height sensor?


height sensor is a sensor that control air compressor on air shock.it keep vechicle level.if height sensor senses distance between frame and suspension .it will admit air to shock by controling the air compressor.check the air shock on driver side.BESURE TO TURN OFF ELECTRICAL POWER TO AIR SUSPENSION BEFORE RAISING VECHICLE.

Jul 10, 2009 | 2000 Ford Expedition

3 Answers

Rear air bag suspension failure 1998 Ford EXP E.B. 2x2


this will get you started. report back on progress and we'll go from there. There is a diagnostic test that will provide codes I think. I will look.

The system consists of unique rear air springs, air compressor, air lines, air spring solenoids, height sensor, air suspension control module, attachments and associated signals derived from both driver and road inputs. With these components and signals, the air suspension control module commands changes in vehicle height that are necessary for the load leveling features.
The load leveling feature rear air suspension (RAS) systems shall automatically make adjustments in vehicle height so that the vehicle is always at trim height and constant front-to-rear vehicle attitudes are maintained over the expected load range of the vehicle. Adjustments in height that are necessary to correct height differences between the vehicle's left and right sides for RAS system shall be restricted to what can be reliably achieved with one air suspension height sensor.
The system uses one air suspension height sensor, a steering sensor, generic electronic module (GEM) transfer case inputs, and other vehicle sensors to measure driver and road inputs. The system changes vehicle height using an air compressor, two air lines, and the use of an air spring with an air spring solenoid.
The air suspension system holds vehicle height when the rear hatch or any door is opened. The system stores rear vehicle height the moment any open door is detected. The system then maintains this height regardless of the addition or removal of a load. The system will return to its commanded height when all doors are closed and the vehicle speed exceeds 16 km/h (10 mph).
Air Suspension Switch
The air suspension switch is located behind the RH kick panel on a mounting bracket. The switch interrupts power to the air suspension control module.
The air suspension switch supplies a signal to the air suspension control module. Without the air suspension control module receiving this signal the load leveling system is inoperative and will not react when rear of the vehicle is raised or lowered. If the air suspension system is disabled by turning off air suspension switch, a "CHECK SUSP" will appear in the RH corner of the instrument cluster with the ignition in the run position.
Air Compressor
The RAS air compressor:
  • Is not interchangeable with four wheel air suspension (4WAS) compressor.
  • Consists of the compressor and vent solenoid; neither are replaceable as individual items.
  • Is mounted in the engine compartment between the washer fluid bottle and headlamp (RH front corner).
  • Is a single cylinder electric motor driven unit that provides pressurized air as required.
  • Is powered by a solid state relay, controlled by the air suspension control module.
  • Passes pressurized air through the compressor air drier that contains silica gel (a drying agent). Moisture is then removed from the compressor air drier when vented air passes out of the system during vent operation.
  • Air drier has a single port and is not interchangeable with 4WAS compressor air drier.
  • Air drier may be replaced separately.
  • Incorporates a snorkle that may be replaced separately.
The vent solenoid:
  • Allows air to escape from the system during venting actions.
  • Is located in the air compressor cylinder head.
  • Has a 160 psi internal relief valve.
  • Shares a common electrical connector with the air compressor motor.
  • Is enclosed in the cylinder head casting, which forms an integral valve housing that allows the valve tip to enter the pressurized side of the system.
  • Has an O-ring seal that prevents air leakage past the valve tip.
  • Opens when the air suspension control module determines lowering is required.
  • Provides an escape route for pressurized air that opens when system pressures exceed safe operating levels.
  • Is replaced with the air compressor as a unit.
Air Spring
RAS vehicles use air springs in the rear. The air springs provide a varying spring rate proportional to the systems air pressure and volume. The air suspension system regulates the air pressure in each air spring by compressing and venting the system air. Increasing air pressure (compressing) raises the rear of the vehicle while decreasing air pressure (venting) lowers the rear of the vehicle. Vehicle height is maintained by the addition and removal of air in each air spring through an air spring solenoid installed in the upper spring cap and energized through the air suspension control module.
The air springs are mounted between the axle spring seats and the frame upper spring seats.
The two air springs replace the conventional rear coil springs.
Air Suspension Height Sensor
When the air suspension height sensor indicates that the rear of the vehicle is lower than trim under normal driving conditions, the air compressor will turn on and pump compressed air to the air springs. When the sensor indicates that the rear of the vehicle is raised above trim under normal driving conditions, this will cause the air to be vented from the air springs to lower the vehicle back to its trim height level.
One air suspension height sensor is mounted on the vehicle. The air suspension height sensor sends a voltage signal to the air suspension control module. The output ranges from approximately 4.75 volts at minimum height (when the vehicle is low or in full jounce), to 0.25 volts at maximum height (when the vehicle is high or in full rebound). The air suspension height sensor has a useable range of 80 mm (3 in) compared to total suspension travel of 200-250 mm (8 to 10 in) at the wheel. Therefore, the air suspension height sensor is mounted to the suspension at a point where full rear suspension travel at the wheel is relative to 80 mm of travel at the air suspension height sensor. The air suspension height sensor is attached between the No. 5 frame crossmember (upper socket) and the panhard rod (lower socket). Replace the air suspension height sensor as a unit.
Compressor Relay
The compressor relay is energized by the air suspension control module to allow high current to flow from the battery to the compressor motor.
  • A solid state relay is used in the air suspension system for air compressor control. The relay incorporates a custom power metal oxide semi-conductor field effect transistor (MOSFET) and ceramic hybrid circuitry. The relay switches high current loads in response to low power signals and is controlled by the logic of the air suspension control module.
Air Suspension Control Module
NOTE: The 4WAS air suspension control module is used for the RAS system. The internal processor recognizes external circuitry to determine if it is installed in a 4WAS or a RAS equipped vehicle.
NOTE: The air suspension control module is calibrated with information from the air suspension height sensor. A new or exchanged air suspension control module requires a ride height adjustment calibration process to be performed.
The air suspension control module controls the air compressor motor (through a solid state relay), and the air spring solenoids. The air suspension control module also provides power to the air suspension height sensor. The air suspension control module controls vehicle height adjustments by monitoring the air suspension height sensor, vehicle speed, a steering sensor, acceleration input, the door ajar signal, transfer case signals, and the brake pedal position (BPP) switch. The air suspension control module also conducts all fail-safe and diagnostic strategies and contains self-test and communication software for testing of the vehicle and related components.
The air suspension control module is mounted in the passenger compartment inside the instrument panel above the radio and temperature controls.
The air suspension control module monitors and controls the air suspension system through a 32-pin two-way connector. The air suspension control module is keyed so that the air suspension control module cannot be plugged into an incorrect harness. There are two sides of the harness connection to the air suspension control module. Each is uniquely colored and keyed to prevent reversing the connections.
Solenoid Valve, Air Spring
swj~us~en~file=ani_caut.gif~gen~ref.gif WARNING: Never rotate an air spring solenoid valve to the release slot in the end cap fitting until all pressurized air has escaped from the spring to prevent damage or injury.
The air spring solenoid:
  • allows air to enter and exit the air spring during leveling operations.
  • is electrically operated and controlled by the air suspension control module.
Air Suspension Diagnostic Connector
The air suspension diagnostic connector is used to aid the technician in diagnosing the air suspension system. It is also used to vent the system of compressed air when air suspension system components need to be repaired or replaced. The air suspension diagnostic connector is located under steering column.

Jun 01, 2009 | 1998 Ford Expedition

1 Answer

EXPEDITION REAR AIR RIDE PROBLEM


do you have just rear air suspension? here's rear only. 4 wheel different. Deler an run a diagnostic test with WDS machine and get fault codes.
-------------------------------------------------------------------------------------
The air suspension system is designed to improve ride, handling and general vehicle performance for static, on-road and off-road driving conditions:
  • Ride is improved by using an air type spring (the soft ride is inherent).
  • Handling is improved by maintaining constant vehicle attitude.
The system consists of unique rear air springs, the air compressor, air lines, air spring solenoids, height sensor, air suspension control module, attachments and associated signals derived from both driver and road inputs. With these components and signals, the air suspension control module commands changes in vehicle height that are necessary for the load leveling features.
The load leveling feature rear air suspension (RAS) systems shall automatically make adjustments in vehicle height so that the vehicle is always at trim height and constant front-to-rear vehicle attitudes are maintained over the expected load range of the vehicle. Adjustments in height that are necessary to correct height differences between the vehicle's left and right sides for the RAS system shall be restricted to what can be reliably achieved with one air suspension height sensor.
The system uses one air suspension height sensor, a steering sensor, generic electronic module (GEM) and other vehicle sensors to measure driver and road inputs. The system changes vehicle height using an air compressor, two air lines and the use of air springs with air spring solenoids.
The air suspension system holds vehicle height when the rear hatch or any door is opened. The system stores rear vehicle height the moment any open door is detected. The system then maintains this height regardless of the addition or removal of a load. The system will return to its commanded height when all doors are closed or the vehicle speed exceeds 16 km/h (10 mph).
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Air Suspension Height Sensor
One air suspension height sensor is mounted on the vehicle. The air suspension height sensor sends a voltage signal to the air suspension control module. The output ranges from approximately 4.75 volts at minimum height (when the vehicle is low or in full jounce), to 0.25 volts at maximum height (when the vehicle is high or in full rebound). The air suspension height sensor has a useable range of 80 mm (3.2 in) compared to total suspension travel of 200-250 mm (8 to 10 in) at the wheel. Therefore, the air suspension height sensor is mounted to the suspension at a point where full rear suspension travel at the wheel is relative to 80 mm (3.2 in) of travel at the air suspension height sensor. The air suspension height sensor is attached between the No. 5 frame crossmember (upper socket) and the panhard rod (lower socket).
When the air suspension height sensor indicates that the rear of the vehicle is lower than trim under normal driving conditions, the air compressor will turn on and pump compressed air to the air springs. When the sensor indicates that the rear of the vehicle is raised above trim under normal driving conditions, this will cause the air to be vented from the air springs to lower the vehicle back to its trim height level
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  • Uneven vehicle height
  • Circuitry.
  • Rear pneumatic fault.
  • Air compressor assembly.
  • Air suspension control module.
  • Go To Pinpoint Test I .

Feb 21, 2009 | 2001 Ford Expedition

1 Answer

20080 sequoia platinum edition with load leveling issue


I think that you need a recalibration of the ride height sensors. Unfortunatly, this can only be done with a tool that the Toyota dealership has in the shop. I just did a Landcruiser with the same suspension, and it took me a while, could NOT get it right, I ended up having to replace one of the height sensors, but there were NO DTC codes in the suspension ECU. You either need a recalibration, or a sensor replacement, followed by a recalibration. I know this may not help you "do it yourself", but, this is what you need. A FixYa rating would be greatly appreciated. Hope I helped you out. Sorry about the sweating in TX. Nice here in PA.

Nov 06, 2008 | 2007 Toyota Sequoia

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