Air suspension leveler not working - 2004 Lincoln Navigator

Anonymous wrote the right answer.

Anonymous Jan 02, 2022

What kind of scan tool ? Will it scan all the modules on the vehicle or is it just OBD2 type ? Did you check wiring diagrams an test electrical circuits for air ride an test with a DVOM - digital volt ohmmeter ? Do you know how to test ALC relay circuits . You replaced a bunch of parts that probably were not needed (,air ride compressor, fuses and ALC relay and the compressor still won't work ) ?

Which of these does your vehicle have

Automatic Level Control
Electronic Suspension Control (ESC)
The vehicles rear leveling compressor motor is switched on and off via a compressor motor relay which is controlled by the suspension control module. The suspension control module provides a switched path to ground whenever compressor activity is required. The suspension control module continually monitors the compressor motor relay circuitry to determine if the voltage level agrees with the commanded state.

DTC C0655 Level Control Compressor Circuit

DTC C0660 Level Control Exhaust Valve Circuit

The exhaust solenoid valve is switched on and off via the suspension control module. The suspension control module provides a switched path to ground whenever exhaust activity is required and during a compressor "head-relief" sequence which occurs at compressor start-up if system pressure is lower than 68.95 kPa (10 psi). The suspension control module continually monitors the exhaust solenoid valve circuitry to determine if the voltage level agrees with the commanded state.

DTC C0711 Level Control Air Pressure Sensor Circuit

Circuit Description
The suspension control module uses a 5-volt analog air pressure sensor to determine the amount of air pressure in the automatic level control (ALC ) system. The valid signal voltage range of the sensor is 0.15-4.85 volts. The sensor signal voltage will increase and decrease within the valid voltage range as system pressure increases and decreases.


Your best bet ,take it to a qualified repair shop that knows what they are doing .

Would need to find out what's wrong first ! The air shock could be bad , ride hight sensor , air line could be broke etc...
The air suspension compressor assembly has the ability to detect faults and indicate the appropriate fault code via a blink code on the inflator switch LED. Is the light on ?
The air suspension compressor assembly will indicate the code when the condition that caused the code is current. In some instances the air suspension compressor assembly may set a flag that requires the ASCM to be reset. The ASCM will reset on its own after the ignition has been turned off for more than 2 1/2 hours or if the air suspension fuse has been removed with the ignition key turned off.

Perform a visual inspection checking for the following:
• Disconnected or damaged air lines.
• Disconnected or damaged air sensor link.
• Disconnected or damaged electrical harness

Trim Height Uneven or Low
Step
Action
Yes
No
Schematic Reference: Suspension Controls Schematics
1
Did you perform the Air Suspension Diagnostic System Check?
Go to Step 2
Go to Diagnostic System Check - Air Suspension
2
Did you review the Air Suspension Description and Operation?
YES - Go to Step 3
NO - Go to Air Suspension Description and Operation
3
Perform a visual inspection checking for the following:
• Disconnected or damaged air lines.
• Disconnected or damaged air sensor link.
• Disconnected or damaged electrical harness.
Did you find and correct the condition?
YES - Go to Step 9
NO - Go to Step 4
4
Cycle the rear compartment inflator switch.
Does the compressor operate?
YES - Go to Step 5
NO - Go to Inflator Inoperative
5
Check the vehicle D-height . Refer to Trim Height Specifications and Trim Height Inspection .
Are the measurements within the specified values?
YES - Go to Step 6
NO - Go to Step 7
6
Perform the air suspension air leak diagnosis. Refer to Air Suspension Air Leak Diagnosis .
Did you find and correct the condition?
YES - Go to Step 10
NO - System OK
7
Recalibrate the air suspension level sensors. Refer to Rear Air Spring Level Sensor Calibration .
Did you find and correct the condition?
YES - Go to Step 10
Go to Step 8
8
Replace the air spring sensor. Refer to Air Spring Leveling Sensor Replacement .
Did you find and correct the condition?
YES - Go to Step 10
NO - Go to Step 9
9
Subtract the Service Preferred Trim Height specification from the value obtained in step 12 of the Air Spring Leveling Sensor replacement procedure.
Add the value to the Service Preferred Trim Height specification. This is the adjusted D-Height measurement.
Repeat the Air Spring Calibration procedure using this value in place of the D-Height specification in step 7 of the Air Spring Calibration procedure.
YES - Did you find and correct the condition?
NO - Go to Step 10
--
10
Operate the system in order to verify the repair.
Did you correct the condition?
System OK
--

Air Suspension ??????

Air Suspension Description and Operation
Air Suspension
The primary mission of the Air Suspension System is the following for the rear suspension under loaded and unloaded conditions:
• Keep the vehicle visually level
• Provide optimal headlight aiming
• Maintain optimal ride height
The Air Suspension System consists of the following items:
• Air suspension compressor assembly
• Air suspension sensors
• Rear air springs
Important: The Air Suspension System must have a voltage supply of at least 12.6V to operate properly.
The Air Suspension System will maintain the rear D height within 4 mm (0.15 in) in all loading conditions and the leveling function will deactivate if the vehicle is overloaded. The side to side D height variation is maintained within 8 mm (0.31 in). After ignition is turned off, the air suspension control module (ASCM) will remain active for between 30 minutes and 2 1/2 hours. The system will exhaust pressure within 30 minutes after the ignition is turned off to lower the vehicle after unloading. In a temperature-controlled environment, the leakage of the complete load leveling system will not result in more than 1.4 mm (0.05 in) drop of rear suspension height at GVWR during a 24 hour period. If the outdoor temperature drops from +20°C (+68°F) to -5°C (+23°F), the rear D height may drop as much as 25 mm (1 in). However, the Air Suspension System should return to the specified D height when the ignition is again cycled to ON.

What is the problem ?

Diagnostic Trouble Code (DTC) Displaying
The Air Suspension system has an internal clock to prevent overheating if the compressor assembly is running for a prolonged period of time. If the system overheats, all leveling function stops until the system cools down. During this time, the indicator LED on the air inflator switch will be quickly flashing at a constant rate.
The other three diagnostic trouble codes are displayed with a blink code on the inflator switch LED. The Air Suspension Compressor Assembly shall begin to indicate the code when the condition to cause the code becomes current.
The number of the fault code shall be represented by the number of flashing pulses on the inflator switch LED. The flashing pulses shall have a repetition rate of 0.5 seconds and each code shall be separated by a 3.0 second delay. All codes shall be flashed in the order of occurrence of the fault. The blink code shall take priority over other processes that have access to the inflator switch LED. Refer to the following:
• DTC 001
• DTC 002
• DTC 003

Trim Height Uneven or Low ??????

Lincoln Town Car Questions - Rear suspension - CarGurus

www.cargurus.com > Questions > Lincoln > Town Car

CarGurusFeb 7, 2015 - Rear suspension - Should the rear airbags deflate after I turn off ...seems to be no leaks cause the pump turns off and I don't hear it going off and on whiledriving. ... dead so you have leak when you jacked up car if not turn off air you could... car pumps up and bleeds off later the problem is NOT the leveler.

2002 Lincoln TC Air suspension not working - CarGurus

www.cargurus.com > Questions > Lincoln > Town Car

CarGurusJul 23, 2012 - 2002 Lincoln TC Air suspension not working - My 2002 TC airsuspension ... 2012 at 09:25 PM about the 2002 Lincoln Town Car Executive ... I did not pay attention that you said the compressor is OK. ... Rear Air Suspension 2 answers ... How can I test my Air suspension height leveling sensor on my 1997 ...

Search Results

1. 2004 Prado Grande Air Suspension Problem - PradoPoint

   www.pradopoint.com > ... > Suspension (120 Series) Dec 18, 2012 - 15 posts - ‎8 authors Found rear suspension not working Hi - Lo / auto level not working at all. Show toToyota dealer, informed air compressor faulty need replacement, but they do ... I have a2003 grande and the same symptoms as mentioned;

check for leaks in the lines, also check to see if the shocks have air leaks.

Hi Jose:
The first place to start is to have Ride Control Module scanned for trouble codes, this requires a high end scan tool. Most common problem is the air compressor in the rear or a height sensor. Here is how the system works.

Automatic Level Control Description and Operation
The RTD system is bi-state real time damping system. The Suspension Control module controls the suspension damper solenoids and suspension position sensors, along with parts of the automatic level control (ALC) system and electronic variable orifice (EVO) power steering system.

The Automatic Level Control system consists of the following:
• Suspension Control Module
• Compressor/Leveling Module
- Air Pressure Sensor
- Exhaust Solenoid
• Compressor Motor Relay

The objective of the Automatic Level Control System is to provide constant ride height at all load conditions. The Suspension Control module monitors body-to-wheel height, and vehicle speed.

The Suspension Control module will use the rear body-to-wheel displacements and vehicle speed inputs to keep the rear trim height of the vehicle at its desired level.

The electronic suspension control (ESC) system is bi-state real time damping system. The ESC module controls the suspension damper solenoids and suspension position sensors, along with parts of the automatic level control (ALC) system, if 1500 series.

The ESC system consists of the following:
• The ESC module
• The compressor/leveling module, if 1500 series
- The air pressure sensor, if 1500 series
- The exhaust solenoid, if 1500 series
• The compressor motor relay, if 1500 series
• The steering handwheel speed/position sensor
• The suspension damper solenoids
• The suspension position sensors

Hope this helps; also keep in mind that your feedback is important and I'll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using Fixya, and have a nice day.

cghk the leveling valve usuall mounted on rear suspension to body.

rear suspension ride leveler mslfunction. Check Air compressor function.

If you have a hole or crack in your airbag the compressor has to work extra hard to try to blow it up (like blowing up a balloon with a hole in it) I would recommend checking out strutmasters.com they have some great kits for the Ninety Eight. There kits will eliminate any problems with the suspension. It is a permanent fix. these convert you from the airbag to a powder coated American made steel coil spring that is guaranteed to last the life of the car. And for a very affordable cost. I added the link below so you can check it out.
http://www.strutmasters.com/oldsmobile-suspension-parts-s/85.htm

Hopefully this will help

Good Luck!!!