Need help with a 2001 Expedition air suspension problems

They eventually wear out. But if you try to replace parts, it will not fix the ongoing problem. You really need to change it to coil suspension. The problem with air ride is the bags will eventually go bad and it cost more to replace them than air bags in the steering wheel. I was lucky. My Expedition had already been changed over

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.

Probably failed seal or air bag leaking air. Check again and try to see if this will do the trick. Sometimes pvc line could fail to deliver air to the bag too!

It sounds like they didn't shut the air suspension before putting it on the lift and hyperextended the bag(s).

The compressor should only run until the rear suspension reaches the desired height. If it continues to run after the suspension has raised to ride height then you may have a leaking air bag/solenoid or line. If you dont have any leaks it is possible the EVO(air suspension module} or relay is at fault.

Any part of the air ride suspension system could have failed.
I would replace the air suspension, with a conversion, such as strutmaster or similar product,other wise you have to diagnose your current system and repair.

The air suspension can be a tricky thing to mess with. When we were looking to replace just one of the rear bags it was going to be costly. My husband did some checking around online and found Strutmasters.com.
They offered great products at a great price and we were very pleased with the outcome of the replacement of the non air system. If you are replacing the entire system you are looking at a pretty penny. I would check Strutmasters out before you replace the air on your Expedition.

the air suspension system is failing,check the suspension switch located behind the passengers side kick panel to see if its on,check the fuses,worst case a hole in the lines to the air bags or bad compressor.about the sunroof-not sure

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.
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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 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.
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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)

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• The compressor is inoperative

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

Sounds like the compressor isnt getting power nor told to do so.

My first step to try for power is to go to the engine bay, Go to the fuse box above the engine and swap the Horn relay for the one in air suspension and try using the horn. If the horn doesnt work theres your problem!

Next step if above fails. Is to check for any blown fuses and replace as needed then retry.

The air suspension also has a height sensor on it, If that has failed the car wouldnt work out where it was and wouldnt adjust. also there is a Air Suspension/Evo Steering Module which controls the system but if there was a problem with this i belive you would also loose power steering.