Airmatic Malfunction Mercedes GL450: Diagnosis & Fix

AIRMATIC Malfunction Mercedes GL450 (X164): Suspension Issue Explained

The Mercedes-Benz GL450 X164 is a full-size luxury SUV designed to deliver supreme comfort and adaptability on any terrain. A major contributor to this comfort is the AIRMATIC suspension system, which adjusts ride height and damping based on speed, load, and driving conditions.

But when an AIRMATIC malfunction warning appears, it can disrupt both ride quality and safety. Symptoms often include sagging suspension, poor handling, or failure to raise or lower the vehicle. In this guide and case study, we’ll explore how to diagnose and fix AIRMATIC suspension problems in the GL450, with a focus on compressor issues, valve block faults, and calibration.

How the GL450 AIRMATIC Suspension Works

The GL450’s AIRMATIC with Adaptive Damping System (ADS) combines pneumatic air springs with electronic damping for precise ride control.

Key Functions:

Ride height adjustment → +80 mm for off-road, –45 mm for high-speed stability.
Automatic level control → Keeps vehicle balanced regardless of load.
Adaptive damping → Adjusts shock absorber stiffness in Comfort, Auto, or Sport mode.

Main Components:

Air suspension struts with integrated ADS dampers.
Electrically driven air compressor.
Valve block and pressure accumulator.
Ride height sensors on each wheel.
AIRMATIC control unit.
Cabin switches for level and damping selection.

This system allows the GL450 to maintain its signature smoothness, but when one component fails, the entire system can be affected.

Common AIRMATIC Faults in Mercedes GL450

Cause	Symptom	Diagnostic & Repair Action
Weak or faulty compressor	Vehicle fails to rise; sagging suspension	Test voltage & pressure; replace compressor if underperforming
Faulty relay or blown fuse	No compressor activity; error warnings	Inspect fuse box; replace faulty relay or fuses
Leaky air struts or valve block	One side lower than the other	Perform soap bubble leak test; replace strut or valve seals
Faulty sensors or ECU communication	Intermittent warnings that reset on restart	Scan with Xentry; replace defective sensor or reprogram control unit

Diagnostic & Repair Workflow for AIRMATIC Malfunction

Ignition ON: Listen for compressor hum; monitor pressure via control module.
Fault code scan: Connect Xentry to read AIRMATIC and ride height sensor codes.
Electrical check: Inspect relays, fuses, and compressor power supply.
Compressor test: Confirm pressure output; replace weak units.
Leak detection: Inspect valve block and struts with soapy water for air leaks.
Component replacement: Fit new compressor, relay, or valve block as required.
Calibration: Recalibrate ride height with Xentry.
System reset: Clear fault codes and test-drive vehicle.

Case Study: AIRMATIC Malfunction in a Mercedes GL450

Complaint

A customer brought in their GL450 X164 after repeatedly seeing the AIRMATIC malfunction warning on the dashboard. Although the warning disappeared upon restarting, it returned after several minutes of driving.

Diagnosis

Fault codes stored in the AIRMATIC module indicated ride height issues.
On startup, the compressor failed to build pressure.
Power supply to the compressor was checked and found normal.
Conclusion: The compressor unit itself was faulty.

Repair

The defective compressor was replaced with a new OEM unit.
The AIRMATIC relay in the fuse box was also replaced (Relay G, located in the right-side engine compartment).
After installation, the system was recalibrated with Xentry to restore proper ride height.

Result

The suspension raised normally, the warning disappeared, and the vehicle was test-driven successfully with no recurrence of the fault.

Mercedes GL450 AIRMATIC Compressor Location

The air suspension compressor is mounted behind the right front fender liner. Access requires partial removal of the fender lining and air intake hose.

GL450 AIRMATIC Compressor Replacement: Step-by-Step

To replace the Air suspension Compressor on a Mercedes GL450, you can follow these steps:

1: Turn off the ignition and place the key fob out of range (at least 2 m) from the transmitter.
2: Remove the front part of the fender lining in the right front fender.
3: Loosen the clamps and remove the air intake hose.
4: Disconnect the electrical connectors.
5: Loosen the pressure line from the AIRMATIC compressor.
6: Unscrew the nuts and remove the AIRMATIC compressor.
7: Replace the AIRmatic relay.

GL450 Airmatic relay location

The Airmatic relay is located in the fuse box in the right side of the engine compartment, as seen in the image below.

GL450 airmatic relay is G, seen in the image below

Symptom – Cause – Fix Table

Symptom	Likely Cause	Repair Solution
Vehicle sagging overnight	Leaky air spring or line	Replace leaking strut or hose
Compressor noisy or overheating	Failing compressor motor	Replace compressor & relay
AIRMATIC malfunction warning	Faulty relay or sensor error	Scan with Xentry; replace relay or sensor
One corner sits lower	Valve block leakage	Replace valve block, recalibrate system
Suspension unresponsive to height button	Control unit or wiring issue	Check ECU communication, repair wiring

Explore More Mercedes Suspension Issues

For a deeper dive into suspension problems such as uneven ride height, AIRMATIC malfunctions, “Stop Vehicle Too Low” warnings, and vibration faults, visit our hub: Mercedes-Benz Suspension Issues – Symptoms, Causes & Fixes. There you’ll find grouped case studies, step-by-step diagnostics, symptom, cause, fix tables, and preventive tips to keep your Mercedes riding smoothly.

How to Reset Mercedes GL450 AIRMATIC Suspension

Resetting can clear minor system faults and reinitialize the control module:

1. Park vehicle on flat surface, engine off.
2. Locate ride height adjustment button near the center console.
3. Press and hold the button for 5–10 seconds.
4. Release and wait for system response (lights flash or system cycles).
5. Turn ignition to ON without starting engine.
6. Check cluster for warnings.
7. If no errors, the reset was successful.
8. For full reset and calibration, use Xentry diagnostics.

FAQs

Q: Can I drive with an AIRMATIC malfunction in my GL450?
A: It’s possible but unsafe. The vehicle may sit too low, reducing handling stability and damaging tires or undercarriage.

Q: How much does it cost to repair AIRMATIC suspension?
A: Compressor replacement costs range from $1,000–$1,500. Valve block or struts can add another $800–$1,200 each.

Q: Should I replace the compressor relay with the compressor?
A: Yes. A worn relay may shorten the life of a new compressor. Always replace both together.

Q: How long does the AIRMATIC compressor last?
A: Typically 6–10 years or ~100,000 miles, depending on usage and maintenance.

Q: Where is the AIRMATIC relay in the GL450?
A: In the fuse box on the right side of the engine compartment. Relay G controls the compressor.

Q: Why does my GL450 sag overnight?
A: Likely due to leaky struts or air lines. A soap-water leak test can confirm the source.

Conclusion

The AIRMATIC suspension system is vital to the Mercedes GL450’s ride quality and adaptability. When malfunctions occur, they usually involve the compressor, relay, valve block, or leaking struts.

In this case study, a faulty compressor was the root cause. By replacing both the compressor and its relay, recalibrating the system, and clearing fault codes, the SUV was restored to its proper stance and comfort.

For GL450 owners, the takeaway is simple: never ignore an AIRMATIC malfunction warning. Early diagnostics with tools like Xentry ensure accurate repairs, prevent costly failures, and keep your Mercedes riding as smoothly as it was designed to.

Author

Written by Mercedes Expert
With years of hands-on experience diagnosing and repairing Mercedes-Benz systems, he brings technical depth and practical case studies to help car owners, technicians, and enthusiasts troubleshoot complex automotive issues. His work focuses on clear repair guides, OEM-level procedures, and knowledge-sharing to empower both professionals and drivers.
Last Updated: September 2025