Air suspension problem

Discussion in 'Range Rover' started by Mrossfly, Mar 10, 2006.

  1. Mrossfly

    Mrossfly Guest

    I have a 2000 HSE with 95K miles. The car ends up in the lowest position
    each morning and can take up to 10 minutes before the compressor will
    lift the car to driving position. Will I need a new compressor???Bags???
    What am I in for at the dealer?
     
  2. joey

    joey Custom Rover Accessories Staff Member

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    If you want it fix back to original, then it will cost you big time..... or you can replace the EAS with Spring for less than half the cost and never worrry again.
     
  3. Who knows what your problem is? In principle, the system seems pretty straightforward and should lend itself to home mechanic troubleshooting. Although I haven't yet had to delve into my system fortunately.

    There are 4 airbags and an air pump for sure. There should be a series of valves to direct air to the appropriate bags for raising the car and to release air to lower. All these valves may be in a single assembly (Like I said, I haven't had to look at my system. I'm just talking out of my ass, now.). And there needs to be some sensors to tell the computer the height at each corner and whether the car is sitting level at all times.

    I can see where this system will require some serious troubleshooting when it's not working correctly. That'll add up in labor costs if the mechanic has to spend a lot of time narrowing down the faulty part. I'll bet that many service departments will just start replacing parts until it seems to be fixed without taking the care necessary to isolate the problem.

    Parts cost are probably expensive. First, because it's Land Rover, and also things like if the valves are all in one assembly, and only one is failing. Well, too, bad you'll have to pay for the entire valve block. But, maybe you can identify and repair the failing valve.

    So back to your problem. Car is dropping all the way down overnight. Sounds like you have an air leak. Where can the system leak from? Could be the air bags, but I think it's unlikely that all 4 are leaking causing all 4 corners to drop. Seems like the leak has to be from a central location so as to affect all 4 corners. Could be an air line leaking. How are all the hoses? Could be a faulty valve or valves (not closing all the way allowing slow leaking). I'd have to see an air line diagram to go further with this.

    As far as not raising for 10 min. Could be the valves not operating correctly again or could be an air leak again. Could be faulty sensors. Could be a failing pump. Lots of possibilities which simply require a systematic approach to troubleshooting.

    Good luck. Report back what you end up doing.

    Brett
     
  4. joey

    joey Custom Rover Accessories Staff Member

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    You want info on the EAS... Here you go.

    Control Unit - ECU

    The ECU is located underneath the front left hand seat. The ECU maintains the requested vehicle ride height by adjusting the volume in each air spring. It is connected to the cable assembly by a 35 way connector. To ensure safe operation the ECU has extensive on board diagnostic and safety features. The ECU must be replaced in case of failure.

    Air compressor
    NOTE: The air compressor and valve block are contained in the under bonnet unit mounted on the left hand inner wing.
    The air compressor provides system pressure. A thermal switch is incorporated which cuts out compressor operation at 120°C . An air filter is fitted to the compressor head. The filter is renewed every 40,000 km (24,000 miles) , or every 30,000 miles in NAS markets

    Air dryer

    The air dryer is connected into the air line between the compressor and reservoir. It is mounted on the engine air cleaner box. The dryer removes moisture from pressurized air entering the system. All air exhausted from the system passes through the dryer in the opposite direction. The air dryer is regenerative in that exhaust air absorbs moisture in the dryer and expels it to atmosphere.

    The air dryer is non-serviceable, designed to last the life of the vehicle. However, if any water is found in the system, the air dryer must be replaced.
    CAUTION: If the air dryer is removed from the vehicle the ports must be plugged to prevent moisture ingress.
    Valve block

    The valve block controls the direction of air flow. Air flow to and from the air springs is controlled by seven solenoid operated valves, one for each spring plus an inlet, exhaust and outlet. In response to signals from the ECU, the valves allow high pressure air to flow in or out of the air springs according to the need to increase or decrease pressure. A diaphragm valve operated by the solenoid outlet valve ensures that all exhausted air passes through the air dryer.

    Mounted on the valve block is a pressure switch which senses air pressure and signals the ECU to operate the compressor when required.The compressor will operate when the pressure falls between 7.2 and 8.0 bar (104 and 116 psi) . It will cut out at a rising pressure of between 9.5 and 10.5 bar (138 and 152 psi).

    The valve block contains the following serviceable components: Solenoid coils 1 to 6, drive pack and pressure switch.

    The valve block must only be dismantled after the correct diagnosis procedure.
     
  5. joey

    joey Custom Rover Accessories Staff Member

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    Reservoir

    The 10 litre reservoir is mounted on the right hand side of the chassis. One connection acts as air inlet and outlet for the rest of the system. The reservoir stores compressed air between set pressure levels. The reservoir drain plug requires removing to check for moisture in the system every 40,000 kms. (24,000 miles) , or every 30,000 miles in NAS markets.

    Height sensors

    Four potentiometer type height sensors signal vehicle height information to the ECU. The potentiometers are mounted on the chassis and activated by links to the front radius arms and rear trailing links. A height sensor must be replaced in case of failure, and the vehicle recalibrated using Testbook.

    Air springs - front and rear

    The air springs consist of the following components:
    1. Top plate
    2. Rolling rubber diaphragm
    3. Piston
    Front and rear air springs are of similar construction but are NOT interchangeable. The diaphragm is not repairable, if failure occurs the complete air spring must be replaced

    Driver controls

    Mounted in the centre of the dashboard, the driver controls consist of an UP/DOWN switch, an INHIBIT switch and a height setting indicator. For full description, refer to Description and Operation/Driver Controls See: Driver Controls

    Relays, fuses

    Located in the under bonnet fuse/relay box are 2 relays, plus 10, 20 and 30 amp fuses.
    DRIVER CONTROLS

    The driver controls are located in the centre of the fascia. The controls consist of:
    1. The HEIGHT CONTROL is a press and release type rocker switch which is used to select the required ride height. The vehicle will not respond until switch is released. All movements selected by operation of this switch are indicated by the ride height indicator lights located next to the switch.
    2. The INHIBIT switch is a mechanically latching switch. When selected it modifies the automatic height changes of the system. Selection of 'inhibit' is indicated by illumination of the switch tell-tale lamp, which is also bulb tested with the ride height indicator.
    3. High indicator light.
    4. Standard indicator light.
    5. Low indicator light.
    6. Access indicator light.
    7. Instrument pack warning light.
    Indicator lights

    When the ignition key is turned to position 2 all four indicator lights, the air suspension warning light and the inhibit switch will be illuminated continuously. When the engine is started, the lights will remain illuminated for 2 seconds, after which the current ride height will be indicated. Two indicators will be illuminated if the vehicle is between ride heights, with the selected height flashing. When the new height is achieved the indicator will be illuminated constantly and the previous height indicator extinguished. The inhibit switch indicator is illuminated while it is activated. Both switches are illuminated with sidelights switched on. Additional driver information is given by the message centre in the instrument pack.

    Air suspension warning lamp

    This amber lamp is located in the instrument pack. The lamp will be constantly illuminated when driving at high ride height and will flash when vehicle is at extended height. The lamp will also illuminate if a fault within the system is detected. A bulb check is provided when the ignition switch is turned to position 2 and for 2 seconds after vehicle start.


    Description

    The Range Rover concept of air suspension is already well established, the system fitted to the New Range Rover is broadly similar. Progressive development has resulted in added features to improve the control and operation of the system.

    Air springs provide a soft and comfortable feel to the ride of the vehicle. The use of a microprocessor to control the system exploits the advantages of air suspension.

    The system provides a near constant ride frequency under all load conditions resulting in:

    Improved ride quality
    Consistency of ride quality
    Constant ride height
    Improved headlamp levelling

    The system provides five ride height settings plus self levelling. Each setting is automatically maintained at the correct height by the system logic with the minimum of driver involvement. Vehicle height is sensed by four rotary potentiometer type height sensors. Height information from each sensor signals the electronic control unit (ECU) to adjust each air spring by switching the solenoid valves to hold, add or release air.

    The five height settings are as follows:
     
  6. joey

    joey Custom Rover Accessories Staff Member

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    Standard: Profile
    Low profile: 25 mm (1 in) below standard.

    Access: 65 mm (2.6 in) below standard. Crawl: It is possible to drive at the access ride height at speeds less than 32 km/h (20 mph), where headroom is restricted.

    High profile: 40 mm (1.6 in) above standard.

    Extended profile: 70 mm (2.75 in) above standard. This setting is not manually selectable.

    Self levelling

    On a coil sprung vehicle the effect of adding weight is for the vehicle to lean either from front to back or side to side unless the increased weight is evenly spread. With air suspension, the system detects this body lean and automatically compensates for it. The vehicle will self level to the lowest corner height for 20 seconds each time the driver exits vehicle and closes the doors.

    The system will check vehicle height every 6 hours and make minor corrections, not exceeding 8 mm, (0.31 in) as necessary.

    When unloading through the tailgate the system will self level to compensate for the decreased load after door closure.
    NOTE: If the vehicle is parked on uneven ground or with a wheel or wheels on the curb, self levelling will lower the vehicle to the lowest spring height
    CAUTION: The underside of the vehicle must be kept clear of any obstacles while the vehicle is parked, as self levelling may result in a reduced trim height.
    WARNING: Before commencing work which requires access to the underside or wheel arches of the vehicle, the suspension must be allowed to relevel. Relevelling is achieved by opening and closing of any of the side doors, while all other doors and tail gate remain closed, and the ignition off.
    EAS must be set in 'high-lock' using Testbook, during any work which does not require chassis to axle displacement. This will hold the suspension in extended profile position, until reset by Testbook.

    The rear suspension design locates the rear axle with two lightweight composite radius arms (1) and a panhard rod (2). The system allows maximum axle articulation and wheel travel while maintaining roll stiffness, directional stability and vehicle refinement. The composite radius arm is mounted to the chassis through a ferrule rubber bush and to the axle using a 'sealed for life' isolation rubber.

    The vehicle height sensors are also linked to the radius arms, for full details of the height settings, refer to Air Suspension/Description and Operation/Height Settings See: Description and Operation

    The panhard rod is mounted to the chassis through ferrule rubber bushes as shown in image

    Conventional telescopic shock absorbers (3) used to control body movement, are secured to the chassis cross frame and a fabricated lower mounting, welded to the axle, that also supports the radius arms. The upper fixing comprises a single bolt passing through a ferrule rubber bush. The lower fixing of the shock absorber comprises of a stem type mount with two rubber bushes and support washers, secured to the axle mounting with a single retaining nut.

    Cellular foam bump stops (4) are fitted under the chassis adjacent to the air springs and prevent any possible damage that could occur should there be excessive axle to chassis movement. Should there be a loss of air pressure in the air springs (5) the vehicle can still be driven safely, at a speed not exceeding35mph (56kph) , with the bump stops resting on the axle, although this will result in a hard ride. The loss of air pressure should be investigated as soon as possible. 'Progressive' bump stops are used and will reform from a compressed state when the load is released.

    HEIGHT SETTINGS

    Standard ride height

    With the Inhibit switch off (unlatched), at speeds below 80 km/h (50 mph) the standard ride height indicator will be illuminated.
    Standard vehicle ride height is maintained under all load conditions. This also maintains headlamp levelling.

    Low ride height

    Low ride height is automatically selected when the vehicle speed exceeds 80 km/h (50 mph) for at least 30 seconds with the inhibit switch off. Low ride height indicator lamp will flash during height change and standard ride height indicator will extinguish when low ride height is attained.

    Standard ride height is automatically selected when the vehicle speed drops below56 km/h (35 mph) for at least 30 seconds with the inhibit switch off.

    The driver can select low ride height at any speed. With the vehicle at low ride height, depressing the inhibit switch (latched) will result in the vehicle maintaining low ride height regardless of speed.

    The height control switch can be used to change between low and standard ride heights regardless of speed.

    Access mode
     
  7. joey

    joey Custom Rover Accessories Staff Member

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    This position eases access to and from the vehicle. With the vehicle stationary, doors and tailgate closed, park brake applied, foot brake released and gearshift in 'Park' on automatic vehicles, press and release the down switch. The vehicle will descend to access mode. While the vehicle is descending, the access indicator will flash. When access mode is attained, the indicator will remain constantly illuminated, and standard ride height lamp will be extinguished.

    Access mode can be selected up to 40 seconds before stopping vehicle. On stopping, applying the hand brake, releasing the foot brake and selecting 'Park' on automatic vehicles, the vehicle will lower to access mode.

    It is possible to select access up to 40 seconds after switching engine off.
    NOTE: Opening a door or tailgate will immediately stop vehicle height change. When the door is closed, the height change will be completed. If the door is open for more than thirty seconds, the system will need 'reminding' of the new height when the door is closed.
    Driving the vehicle will result in vehicle rising automatically to standard ride height. Alternatively standard ride height can be achieved by closing all doors, starting engine and pressing the up switch. The standard indicator will flash during the change. When standard ride height is attained the indicator will remain constantly illuminated and access indicator will be extinguished.

    Crawl mode

    In areas where height is restricted, the vehicle may be driven in access mode. To achieve this, ensure the inhibit switch is unlatched and select access mode. When access height is achieved, press the inhibit switch, the lamp will be illuminated. The message centre in the instrument binnacle will beep three times and display EAS MANUAL . The vehicle may now be driven at speeds up to 32 km/h (20 mph) .

    If the vehicle is accelerated to 16 km/h (10 mph) the message centre will beep three times and display SLOW 20 MPH (32 KM/H) MAX.

    If speed exceeds 40 km/h (25 mph) the vehicle will rise to low profile, with low warning flashing. On slowing to 32 km/h (20 mph) the vehicle will lower to access mode with access warning illuminated.

    When speed falls below 8 km/h (5 mph) the message centre will beep three times and display EAS MANUAL .

    To cancel crawl mode, release the inhibit switch or depress the up switch.

    High ride height

    This position is used to improve approach and departure angles and when wading. When at standard ride height, pressing the up switch will select high ride height provided the road speed is below 56 km/h (35 mph). The high ride height indicator will flash during the height change. When the change is complete the indicator will remain constantly illuminated, and standard ride height indicator will be extinguished. The indicator in the instrument pack will also be illuminated. It speed exceeds 56 km/h (35 mph) , the vehicle will return to standard profile.

    Extended ride height

    This position is achieved if chassis is grounded leaving wheel or wheels unsupported. Initial ECU reaction is to lower (deflate) affected springs. After a timed period the ECU detects no height change, it therefore reinflates springs to extended profile in an attempt to regain traction. The position will be held for 10 minutes, after which time the vehicle will automatically return to standard ride height.

    Pressing the down switch will lower vehicle 20 mm to high profile.

    If vehicle speed exceeds 56 km/h (35 mph) the vehicle will immediately lower to standard ride height. This speed could be achieved, for example, by wheel spin.
    HEIGHT SETTINGS

    Standard ride height

    With the Inhibit switch off (unlatched), at speeds below 80 km/h (50 mph) the standard ride height indicator will be illuminated.
    Standard vehicle ride height is maintained under all load conditions. This also maintains headlamp levelling.

    Low ride height

    Low ride height is automatically selected when the vehicle speed exceeds 80 km/h (50 mph) for at least 30 seconds with the inhibit switch off. Low ride height indicator lamp will flash during height change and standard ride height indicator will extinguish when low ride height is attained.

    Standard ride height is automatically selected when the vehicle speed drops below56 km/h (35 mph) for at least 30 seconds with the inhibit switch off.

    The driver can select low ride height at any speed. With the vehicle at low ride height, depressing the inhibit switch (latched) will result in the vehicle maintaining low ride height regardless of speed.

    The height control switch can be used to change between low and standard ride heights regardless of speed.

    Access mode
     
  8. joey

    joey Custom Rover Accessories Staff Member

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    This position eases access to and from the vehicle. With the vehicle stationary, doors and tailgate closed, park brake applied, foot brake released and gearshift in 'Park' on automatic vehicles, press and release the down switch. The vehicle will descend to access mode. While the vehicle is descending, the access indicator will flash. When access mode is attained, the indicator will remain constantly illuminated, and standard ride height lamp will be extinguished.

    Access mode can be selected up to 40 seconds before stopping vehicle. On stopping, applying the hand brake, releasing the foot brake and selecting 'Park' on automatic vehicles, the vehicle will lower to access mode.

    It is possible to select access up to 40 seconds after switching engine off.
    NOTE: Opening a door or tailgate will immediately stop vehicle height change. When the door is closed, the height change will be completed. If the door is open for more than thirty seconds, the system will need 'reminding' of the new height when the door is closed.
    Driving the vehicle will result in vehicle rising automatically to standard ride height. Alternatively standard ride height can be achieved by closing all doors, starting engine and pressing the up switch. The standard indicator will flash during the change. When standard ride height is attained the indicator will remain constantly illuminated and access indicator will be extinguished.

    Crawl mode

    In areas where height is restricted, the vehicle may be driven in access mode. To achieve this, ensure the inhibit switch is unlatched and select access mode. When access height is achieved, press the inhibit switch, the lamp will be illuminated. The message centre in the instrument binnacle will beep three times and display EAS MANUAL . The vehicle may now be driven at speeds up to 32 km/h (20 mph) .

    If the vehicle is accelerated to 16 km/h (10 mph) the message centre will beep three times and display SLOW 20 MPH (32 KM/H) MAX.

    If speed exceeds 40 km/h (25 mph) the vehicle will rise to low profile, with low warning flashing. On slowing to 32 km/h (20 mph) the vehicle will lower to access mode with access warning illuminated.

    When speed falls below 8 km/h (5 mph) the message centre will beep three times and display EAS MANUAL .

    To cancel crawl mode, release the inhibit switch or depress the up switch.

    High ride height

    This position is used to improve approach and departure angles and when wading. When at standard ride height, pressing the up switch will select high ride height provided the road speed is below 56 km/h (35 mph). The high ride height indicator will flash during the height change. When the change is complete the indicator will remain constantly illuminated, and standard ride height indicator will be extinguished. The indicator in the instrument pack will also be illuminated. It speed exceeds 56 km/h (35 mph) , the vehicle will return to standard profile.

    Extended ride height

    This position is achieved if chassis is grounded leaving wheel or wheels unsupported. Initial ECU reaction is to lower (deflate) affected springs. After a timed period the ECU detects no height change, it therefore reinflates springs to extended profile in an attempt to regain traction. The position will be held for 10 minutes, after which time the vehicle will automatically return to standard ride height.

    Pressing the down switch will lower vehicle 20 mm to high profile.

    If vehicle speed exceeds 56 km/h (35 mph) the vehicle will immediately lower to standard ride height. This speed could be achieved, for example, by wheel spin.
    VEHICLE TRANSPORTATION

    New vehicles are transported from the factory with the EAS system electronically 'frozen' in access mode. When road speed exceeds 40 km/h (25 mph), the vehicle will rise to low ride height. It will return to access mode it speed falls below 38.4 km/h (24 mph). This condition is cancelled at pre-delivery inspection, by entering the appropriate command via Testbook.

    Vehicle transportation/recovery
    CAUTION: When an air suspension vehicle is secured to a transporter using the chassis lashing eyes, there is a possibility due to air leakage, self levelling or operation of ride height controls that the tension of the securing straps will be lost. To prevent this the ride height should be set to access mode before securing to transporter.
    If the engine cannot be run and the vehicle is not in access mode, the vehicle can be transported, but it must be secured to the transporter by the roadwheels, not the chassis.
     
  9. hahaha. Now that's what I call a post. If you actually typed all that, you're my hero. :) Now tell me about the climate control and why the driver's side doesn't get as hot as the passenger's and why I hear what sounds like a flap loudly closing and opening at random times coming from under the dash. (Not to hijack this thread or anything)

    Brett
     
  10. joey

    joey Custom Rover Accessories Staff Member

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    P38 Heater Control TSB.
    SUBJECT:
    PRIDE - Heater Core Sensor Replacement

    MODEL:
    Range Rover 4.0/4.6

    AFFECTED VEHICLES: LP Up to TA344173
    LH
    LJ
    LD

    DETAIL

    There has been a reliability concern identified with the heater core sensor. A faulty heater core sensor may cause abnormal air distribution or temperature control.

    Proper diagnosis of the heater core sensor is to be carried out as per the Operation Pride HVAC specification document. The sensor may have faulty soldering which will cause an open circuit or inaccurate temperature measurement.

    The sensor supplier has remedied the issue and parts stock contains only reliable sensors.

    The diagnostic steps and repair procedures detailed in this bulletin were developed as an element of the Land Rover Way Operation PRIDE. This TIB provides a library location for PRIDE information within the Land Rover North America technical literature system.

    ACTION REQUIRED

    Replacement of faulty heater core sensor

    PARTS INFORMATION

    STC 3256 Heater Core Sensor

    PROCEDURE

    Perform TestBook troubleshooting to determine if DTC 49 or DTC 50 is present.

    Note: If there is a fault in the heater core sensor circuit that causes hot air from the vents, selecting LO/LO will result in cold air. Diagnose the fault as detailed below:

    1. (DTC 49) Check for continuity between C221 pin 2 and C246B pin 2 (signal).

    2. (DTC 49) Check for short to +12V between C221 pin 2 and C246B pin 2 (signal).

    3. (DTC 50) Check for short to ground between C221 pin 2 and C246B pin 2 (signal).


    If trouble codes or symptoms indicate heater core sensor fault, follow the instructions for removal and replacement

    WARRANTY:

    Normal warranty policy and procedures apply.

    COMP.CODE:

    SR0:

    82.20.94 - Heater core sensor renew 0.35 hr.

    Removal

    1. Open glove box. Remove 5 screws securing glove box liner to fascia.








    2. Lower glove box liner. Release 2 clips to disengage glove box release cable latch from location.

    3. Locate heater core sensor on inlet pipe of heater core.








    4. Disconnect heater core sensor from pipe and disconnect heater core sensor multiplug.








    Test Procedure 3: Solar Sensor and Temperature Sensor Circuits

    5. Check for continuity between C221 pin 1 and C246B pin 10 (reference ground).








    6. Check sensor resistance at ambient temperature.

    7. If the problem is intermittent, check the build date number stamped on the top of sensor. The last two digits should be 46, 56, 66,or higher (46 corresponding to 4/96). If sensor has a build date prior to 4/96, it may be faulty.

    8. If any of the above tests and inspections indicate a faulty sensor, replace the sensor with STC3256.


    Replacement

    1. Refit sensor to heater core inlet tube.

    2. Reconnect heater core sensor multiplug to vehicle harness.

    3. Refit glove box release cable latch.

    4. Refit glove box liner to fascia and secure with 5 screws.
     

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