My rear air suspension doesnt air up

will need a meter to test and check the system --stated compressor seems fine is not a diagnosis of it need to test components for overheat failed or loose connections harness --also for air leak

Sounds like you need to check the air-bags for a leak. Unfortunately, the compressor may have wore itself out attempting to continuously provide air to the air-bag and may also need replacing. Just my $0.02 worth.

Would need to know what DTC'S - diagnostic trouble codes are stored in the module for the autoride suspension . Hooking up a professional type scan tool ,looking at input data to the module etc... Looking at a wiring diagram an testing electrical circuit's using a DMM - digital multi-meter . Reading how the system works ,what all involved in making the system work . This is how a professional Tech would go about diagnosing this .

The automatic level control (ALC) system maintains a desired rear suspension position under all types of towing, hauling and loading conditions. The following components are involved in the operation of the ALC system:
• Air line tubing--Pressurized air from the ALC compressor is pumped to each of the rear shocks via air line tubing.
• Air drier--Pressurized air from the compressor is run through a drier containing a moisture absorbing chemical preventing water accumulation in the rear shocks.
• Compressor--Supplies pressurized air to the rear shocks
• Compressor motor relay--The relay supplies battery positive voltage to the ALC compressor motor.
• Pressure sensor--The electronic suspension control module (ESCM) module provides a 5-volt reference and low reference to the ALC pressure sensor. The module receives the signal voltage that is relative to the air pressure applied to the rear shocks.
• ESCM--Controls the ALC system and electronic suspension control (ESC) system and detects failures in both. The module monitors inputs from the position sensors, and pressure sensor to determine when to raise and lower the vehicle to trim height as the vehicle is loaded or unloaded. The module limits pump activation to 255 seconds to prevent thermal damage.
• Exhaust valve--An electric solenoid activated by the ESCM to vent air pressure from the rear shocks.
• Left and right rear suspension position sensors--The module provides a 5-volt reference and low reference to all 4 of the body-to-wheel suspension position sensors. The sensors send the ESCM a signal voltage that is relative to the rear suspension ride height
• Left and right rear shock absorbers with internal air chambers and dampers--Dampens the rear suspension and maintains trim height depending on the air pressure applied.

Your best bet take it an have it diagnosed ! This is computer controlled an may have DTC'S - diagnostic trouble codes stored !
C1724 Air Suspension Height Sensor Power Circuit Failure Air Suspension Control Module GO to Pinpoint Test F . C1726 Air Suspension Rear Pneumatic Failure Air Suspension Control Module GO to Pinpoint Test G . C1760 Air Suspension Rear 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
Symptom Chart Condition Possible Sources Action

• No communication with the air suspension control module

• CJB Fuse 4 (15A), 6 (5A) and 20 (5A).
• Circuitry.
• Air suspension control module.
• Air suspension switch.

• GO to Pinpoint Test A .

You replaced a part that you probably didn't need !

• The compressor is inoperative

• BJB Fuse 109 (50A).
• Air compressor assembly.
• Circuitry.
• Air suspension relay.

• GO to Pinpoint Test Q .

There is a lot to this system an guessing as to what the problem is ,isn't the way to fix it.
Measure the voltage between air compressor relay C1000 Pin A, Circuit 1053 (LB/PK), harness side and ground.

• Is the voltage greater than 10 volts?

Yes GO to Q3 .

No REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
Measure the resistance between air compressor C1000 Pin B, Circuit 538 (GY/RD), harness side and air compressor assembly C194M Pin 4, Circuit 538 (GY/RD), harness side.

• Is the resistance less than 5 ohms?

Yes GO to Q4 .

No REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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). Replace the air suspension height sensor as a unit.
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.

Having it hooked up to a factory scan tool would be your best bet . Check for DTC'S diagnostic trouble codes . Without testing ,code scan ,we'd only be guessing .
Very complex , the untrained person hasn't got a pray of fixing this . You have no idea what your dealing with . 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).
• Rear Air Suspension Control Module Diagnostic Trouble Code (DTC) Index DTC Description Source Action B1317 Battery Voltage High Rear Air Suspension Control Module GO to Pinpoint Test C . B1318 Battery Voltage Low Rear Air Suspension Control Module GO to Pinpoint Test C . B1342 ECU Is Defective Rear Air Suspension Control Module INSTALL a new rear air suspension control module. REFER to Module-Air Suspension Control . TEST the system for normal operation. C1441 Steering Sensor Channel A Circuit Failure Rear Air Suspension Control Module REFER to Section 211-00 . C1442 Steering Sensor Channel B Circuit Failure Rear Air Suspension Control Module REFER to Section 211-00 . C1722 Air Suspension Height Sensor Power Circuit Short to Power Rear Air Suspension Control Module GO to Pinpoint Test D . C1723 Air Suspension Height Sensor Power Circuit Short to Ground Rear Air Suspension Control Module GO to Pinpoint Test E . C1760 Air Suspension Rear Height Sensor High Signal Circuit Failure Rear Air Suspension Control Module GO to Pinpoint Test F . C1763 Air Suspension Rear Height Sensor High Signal Circuit Short to Ground Rear Air Suspension Control Module GO to Pinpoint Test G . C1765 Air Suspension Rear Height Sensor Low Signal Circuit Failure Rear Air Suspension Control Module GO to Pinpoint Test F . C1768 Air Suspension Rear Height Sensor Low Signal Circuit Short to Ground Rear Air Suspension Control Module GO to Pinpoint Test H . C1770 Air Suspension Vent Solenoid Output Circuit Failure Rear Air Suspension Control Module GO to Pinpoint Test I . C1773 Air Suspension Vent Solenoid Output Circuit Short to Ground Rear Air Suspension Control Module GO to Pinpoint Test J . C1790 Air Suspension LR Air Spring Solenoid Output Circuit Failure Rear Air Suspension Control Module GO to Pinpoint Test K . C1793 Air Suspension LR Air Spring Solenoid Output Circuit Short to Ground Rear Air Suspension Control Module GO to Pinpoint Test L . C1795 Air Suspension RR Air Spring Solenoid Output Circuit Failure Rear Air Suspension Control Module GO to Pinpoint Test M . C1798 Air Suspension RR Air Spring Solenoid Output Circuit Short to Ground Rear Air Suspension Control Module GO to Pinpoint Test N . C1813 Air Suspension Vent Request Exceeded Max Timing Rear Air Suspension Control Module GO to Pinpoint Test O . C1818 Air Suspension Air Compressor Request Exceeded Max Timing Rear Air Suspension Control Module GO to Pinpoint Test P . C1830 Air Compressor Relay Circuit Failure Rear Air Suspension Control Module GO to Pinpoint Test Q . C1832 Air Compressor Relay Circuit Short to Power Rear Air Suspension Control Module GO to Pinpoint Test R . C1840 Air Suspension Switch Circuit Failure Rear Air Suspension Control Module GO to Pinpoint Test S . C1842 Air Suspension Switch Circuit Short to Power Rear Air Suspension Control Module GO to Pinpoint Test D . C1897 Steering VAPS Circuit Loop Failure Rear Air Suspension Control Module REFER to Section 211-00 . U1041 SPC Invalid or Missing Data for Vehicle Speed

Check the air lines for leaks especially around the right rear tire area. chances are the flat tire severed or pulled loose one of the lines from compressor

Problems with the air suspension seem to be less frequent with the Sport than in previous Range Rover models, but they still do occur. One owner reports "Whenever my RRS is lowered to "access" level a suspension system fault message apprears.". Another reports " Had the RRS back less than 2 hours and another "suspension fault." Also kept receiving messages that the vehicle is raising slowly and vehicle will raise when system cools. Couldn't even drive because it wouldn't raise out of access mode. Anyway, back to the dealer. Picked the RRS up again today-dealer said the EAS compressor was faulty and replaced it. So far everything is ok." Overall, most of the problems seem to be related to bad suspension height sensors or bad compressors. Angus Wade of the Czech Republic had his suspension light come on when in Germany; it started yellow and then red, then disappeared when he stopped and restarted the engine -- and has not happened since. His dealer said they have seen this a bit.

Weak Compressor: An official Technical Service Bulletin (TSB) LS-204-004 addresses "ELECTRONIC AIR SUSPENSION (EAS) WARNING MESSAGE AND LAMP ILLUMINATION". This deals with the warning message "Suspension Fault - Normal Height Only" message appearing with the Air Suspension Warning Lamp on. Computer diagnosis shows pressure increasing too slowly or unable to pressurize, with no air leaks. The usual problem is the compressor exhaust valve sticking, causing an internal air leak when the compressor is active. The bulletin recommends renewing the air compressor (RQG500090 is the latest specification air compressor with a stronger exhaust valve return spring)and installing and updating the air suspension control module software using WDS disc 13 or later.

Suspension Fault Message (random): One owner reported getting random suspension fault messages on his brand new RR Sport purchased in June 2006, well after the fix was in for the weak compressor. His suspension Fault message and Suspension Warning Light (Amber) came on after 5 days of ownership. He stopped and restarted the car, which caused the light and message to disappear, but they came on again after 5 minutes. Later the same day, the warnings disappeared again.

I have heard that on 2006 models, EAS fault messages can be caused by an internal leak in the Air Suspension compressor exhaust valve. The fix is said to be replacing the compressor updating the software.

Hope helps.

Problems with the air suspension seem to be less frequent with the Sport than in previous Range Rover models, but they still do occur. One owner reports "Whenever my RRS is lowered to "access" level a suspension system fault message apprears.". Another reports " Had the RRS back less than 2 hours and another "suspension fault." Also kept receiving messages that the vehicle is raising slowly and vehicle will raise when system cools. Couldn't even drive because it wouldn't raise out of access mode. Anyway, back to the dealer. Picked the RRS up again today-dealer said the EAS compressor was faulty and replaced it. So far everything is ok." Overall, most of the problems seem to be related to bad suspension height sensors or bad compressors. Angus Wade of the Czech Republic had his suspension light come on when in Germany; it started yellow and then red, then disappeared when he stopped and restarted the engine -- and has not happened since. His dealer said they have seen this a bit.

Weak Compressor: An official Technical Service Bulletin (TSB) LS-204-004 addresses "ELECTRONIC AIR SUSPENSION (EAS) WARNING MESSAGE AND LAMP ILLUMINATION". This deals with the warning message "Suspension Fault - Normal Height Only" message appearing with the Air Suspension Warning Lamp on. Computer diagnosis shows pressure increasing too slowly or unable to pressurize, with no air leaks. The usual problem is the compressor exhaust valve sticking, causing an internal air leak when the compressor is active. The bulletin recommends renewing the air compressor (RQG500090 is the latest specification air compressor with a stronger exhaust valve return spring)and installing and updating the air suspension control module software using WDS disc 13 or later.

Suspension Fault Message (random): One owner reported getting random suspension fault messages on his brand new RR Sport purchased in June 2006, well after the fix was in for the weak compressor. His suspension Fault message and Suspension Warning Light (Amber) came on after 5 days of ownership. He stopped and restarted the car, which caused the light and message to disappear, but they came on again after 5 minutes. Later the same day, the warnings disappeared again.

I have heard that on 2006 models, EAS fault messages can be caused by an internal leak in the Air Suspension compressor exhaust valve. The fix is said to be replacing the compressor updating the software.

Hope helps.

More than likely you have an inner leak in one of the strut assem. in rear.

It could be a wheel speed sensor that went out or something... When working with the wiring, something could have just gotten crossed or tapped to get these codes as well. The compressor shouldnt be running anymore if everything was tied off properly. Take it in somewhere and have the codes cleared and that should fix the problem hopefully. I know AutoZone has a reader, but I do not know if they have they ability to clear the codes.
I hope this helps.