Question about 1990 BMW 5 Series

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Suspension problem - 1990 BMW 5 Series

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  • Steve
    Steve May 11, 2010

    what is your suspension problem

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Need to know what the problem is to help dude

Posted on Jul 11, 2009

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    May 16, 2016 | 2004 Land Rover Range Rover

    2 Answers

    Need a diagram for front suspension for volvo 960


    Richard, you really should get a manual. last link manual is free.
    Check the attached links,instruction and guides, Good luck
    "I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."
    1997 Volvo 960 front suspension Google Search

    Volvo Strut Replacement 850 Front Struts Mounts Spring Seats Suspension...

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    Mar 24, 2016 | 1997 Volvo 960

    1 Answer

    Rear suspension will deflate but why won't it inflate?


    That could work , You mite be able to test the sensor in question with ohm meter . Test the front one an see what the resistance is ,then check the back one. I don't know what it should be with out looking it up in the service info . You could also check to see if the sensor is getting power from the control module , an see if there is a return input to the module .
    There are a few DTC'S this able to set !
    Air Suspension Control Module Diagnostic Trouble Code (DTC) Index
    Air Suspension Control Module Diagnostic Trouble Code (DTC) Index DTCs Description Source Action B1318 Battery Voltage Low Air Suspension Control Module Go To Pinpoint Test C . B1342 Air Suspension Control Module Air Suspension Control Module INSTALL a new air suspension control module. REFER to Module-Air Suspension Control . SET the front ride height. REFER to Air Suspension Initialization (Clear DTC B2140). CLEAR the DTCs. REPEAT the self-test. B1485 Brake Pedal Input Circuit Battery Short Air Suspension Control Module RERUN On-Demand Self-Test. MAKE SURE that the brake pedal is not pressed. If DTC is returned again, REPAIR brake pedal position (BPP) circuitry. B1566 Door Ajar Circuit Short to Ground Air Suspension Control Module Go To Pinpoint Test D . B2140 Initialization Failure (Vehicle Ride Height Not Programmed) Air Suspension Control Module REFER to Air Suspension Initialization (Clear DTC B2140). C1439 Vehicle Acceleration EEC-V Circuit Failure Air Suspension Control Module Go To Pinpoint Test E . C1724 Air Suspension Height Sensor Power Circuit Failure Air Suspension Control Module Go To Pinpoint Test F . C1726 Air Suspension Pneumatic Failure Air Suspension Control Module Go To Pinpoint Test G . C1760 Air Suspension Height Sensor High Signal Circuit Failure Air Suspension Control Module Go To Pinpoint Test H . C1770 Air Suspension Vent Solenoid Output Circuit Failure Air Suspension Control Module Go To Pinpoint Test I . C1790 Air Suspension LR Air Spring Solenoid Output Circuit Failure Air Suspension Control Module Go To Pinpoint Test J . C1795 Air Suspension RR Air Spring Solenoid Output Circuit Failure Air Suspension Control Module Go To Pinpoint Test K . C1830 Air Suspension Compressor Relay Circuit Failure Air Suspension Control Module Go To Pinpoint Test L . C1917 Steering Electronic Variable Orifice (EEVO) Out-of-Range Fault Air Suspension Control Module Go To Pinpoint Test Q .
    • Uneven vehicle height
    • Circuitry.
    • Rear pneumatic fault.
    • Air compressor assembly.
    • Air suspension control module.
    • Go To Pinpoint Test I .

    Nov 06, 2015 | 2002 Lincoln Navigator

    2 Answers

    Air suspension


    LEAK IS AIR LINE FROM COMPRESSOR TO REAR SUSPENSION
    OR...REAR SUSPENSION COMPONENT FAILURE

    Jul 21, 2013 | 2003 Oldsmobile Bravada

    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

    1 Answer

    Where can i get a copy of the parts that make up the air suspesion of my 2001 grand marquis. sometime it works and other time it will not.


    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
    ------------------------------------------------
    Visual Inspection Chart Mechanical Electrical
    • Restricted suspension movement
    • Excessive vehicle load
    • Cut, severed, or crimped air line(s)
    • Damaged air spring(s)
    • Height sensor damage
    • Height sensor mounted incorrectly, disconnected, or damaged
    • Central junction box (CJB):
      • Fuse 5 (15A)
    • Battery junction box (BJB):
      • Fuse 8 (30A)
    • Loose or corroded connectors
    • Air suspension switch OFF


    The air suspension control module is diagnosed using Super Star II Tester 418-F045 (007-0041B) or equivalent.
    The test connector used to communicate with the air suspension control module is located on the RH side of the luggage compartment.
    When the tester is connected, the engine is started and the HOLD/TEST button is latched down, the air suspension control module will respond sending a code 10 to the Super Star II Tester which represents "Diagnostics mode entered." If diagnostic trouble code (DTC) 10 is not displayed, go to Pinpoint Test A.
    Air Suspension Control Module Diagnostic Trouble Code (DTC) Index
    Condition Possible Sources Action
    • No communication with the air suspension control module
    • CJB Fuse 5 (15A).
    • BJB Fuse 8 (30A).
    • Circuitry.
    • Air suspension control module.
    • GO to Pinpoint Test A .
    • Unable to enter auto test
    • Air suspension control module.
    • Circuitry.
    • GO to Pinpoint Test B .
    • Rear air suspension does not respond to load changes
    • Circuitry.
    • Air compressor.
    • Air compressor inlet tube.
    • Air compressor drier.
    • Air suspension height sensor.
    • Air suspension control module.
    • GO to Pinpoint Test C .
    • Rear rides low/high
    • Circuitry.
    • Air spring solenoid.
    • Air suspension height sensor.
    • Air suspension control module.
    • GO to Pinpoint Test C .
    • Poor ride quality
    • Circuitry.
    • Air springs.
    • GO to Pinpoint Test C .
    • Air suspension warning indicator ON
    • Air suspension switch OFF.
    • Place the air suspension switch in the ON position.
    • Air suspension control module.
    • Circuitry.
    • GO to Auto Test.
    • Instrument cluster (conventional cluster) or lamp warning module (electronic cluster).
    • REFER to Section 413-01A (conventional cluster) or REFER to Section 413-01B (electronic cluster), or REFER to Section 413-01C (natural gas cluster).


    Sep 25, 2009 | 2001 Mercury Grand Marquis

    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

    2 Answers

    No power to rear bags its down but wont air up bags dont seem cracked unplugged connector no power I tried resetting still no power


    is switch on?
    The air suspension switch and bracket is mounted below the RH side of the instrument panel.

    Dealer can run diagnostic test with scan tool for 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).
    ------------------------------------
    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 two air springs support the conventional rear leaf coil springs.
    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.
    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 the vehicle and related components.
    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.
    ------------------------------------------------------------------------
    Visual Inspection Chart Mechanical Electrical
    • Restricted suspension movement
    • Excessive vehicle load
    • Cut, severed or crimped air line(s)
    • Unmounted height sensor
    • Damaged air spring(s)
    • Open fuses:
      • Central junction box (CJB) Fuse 4 (15A), 6 (5A) and 20 (5A)
      • Battery junction box (BJB) Fuse 109 (50A)
    • Loose, corroded or disconnected connectors
    • Air suspension switch is in the OFF position
    • Damaged solenoid valve(s)


    -----------------------------------------------------------
    • The compressor is inoperative
    • BJB Fuse 109 (50A).
    • Air compressor assembly.
    • Circuitry.
    • Air suspension relay.

    Apr 30, 2009 | 2000 Ford Expedition

    1 Answer

    Airride suspension won't deflate only inflate


    It will only process a "down command" if it thinks all the doors are closed. If you have a bad door switch, it won't lower. Any courtesy lights on with doors closed?
    The dealer can conduct a diagnostic scan test and retrieve any codes that will help identify the bad circuit. Did they do that?

    Do you have 4 wheel air suspension or just rear?

    Assuming rear only:
    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.

    Note this section.
    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).

    Air Suspension Switch
    The air suspension switch supplies power to the air suspension control module. Without the air suspension control module receiving this power, the load leveling system is inoperative and will not react when the rear of the vehicle is raised or lowered. If the air suspension system is disabled by turning off the air suspension switch, a "CHECK SUSP" will appear in the RH corner of the instrument cluster with the ignition in the run position.
    --------------------------------------------------------------------
    The vent solenoid:
    • allows air to escape from the system during venting actions.
    • is part of the air compressor cylinder head.
    • has a 1,103 kPa (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 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.
    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 the vehicle and related components.
    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.
    ---------------------------------------------------
    May be a bad module too.

    Apr 11, 2009 | 2000 Lincoln Navigator

    1 Answer

    I have a 1998 ford expedition eddie bauer with front air bag suspension and after driving for about 45 minutes the air suspension light comes on. what's the problem and how do I fix it


    here's some info. Do you have a warning light on or does it say "Check Susp"?

    Control Module
    NOTE: The 4-wheel air suspension (4WAS) control module is also used for the rear air suspension (RAS) system. The internal processor recognizes external circuitry to determine if it is installed in a 4WAS or a RAS system.
    NOTE: The air suspension control module is calibrated with information from the air suspension height sensors. A new or swapped air suspension control module requires the ride height adjustment calibration process to be performed.
    A microcontroller-based electronic air suspension control module controls the air compressor motor (through a solid state relay), and all system solenoids. The air suspension control module also provides power to front and rear height sensors. The air suspension control module controls vehicle height adjustments by monitoring the two height sensors, 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 is interchangeable between the RAS and 4WAS system.
    The air suspension control module monitors and controls the system through a 32-pin two-way connector. The air suspension control module is keyed so that it 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, 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.
    • Is only replaced as a unit.
    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 the steering column.
    Steering Sensor
    The steering sensor is mounted inside the passenger compartment on the steering column. It provides steering rate and position to the air suspension control module through two signals.
    Pressure Relief Valve
    The pressure relief valve (PRV) protects the rear air suspension components by venting the system to a specific pressure in the case of a system malfunction. The system will decrease the pressure to an acceptable level to maintain vehicle height. In the normal operation mode with normal system pressure the PRV is constantly closed and does not have any effect on the system performance or function. The PRV is replaceable without any air lines.
    The PRV is located in the rear of the vehicle on the middle of crossmember #5 as a part of the rear air line assembly.

    Mar 09, 2009 | 1998 Ford Expedition

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