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2018 Navigator Reserve Air Suspension Sagging & Compressor Noise

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David L. · rep 0 · May 22, 6:05 AM · 1 replies · solved · Question

Vehicle: 2018 Lincoln Navigator Reserve

Hey everyone, I'm having some trouble with the air suspension on my 2018 Lincoln Navigator Reserve. Lately, I've noticed the rear end sags significantly overnight, sometimes even after just a few hours. When I start it up, the compressor runs for a good while, much longer than it used to, and it sounds pretty loud.

I've also started getting a 'Service Air Suspension' message on the dash intermittently. It usually clears after the compressor runs, but it's concerning. The ride quality also feels a bit off, especially over bumps.

Has anyone experienced this with their Navigator or other Lincoln models with air suspension? What was the fix? I'm trying to figure out if this is a common issue or something more serious. Any advice on what to check first would be greatly appreciated before I take it to the dealer.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 6:05 AM

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ClearTheCode admin answer:

It sounds like you're dealing with a common issue for vehicles equipped with air suspension systems, particularly the 2018 Lincoln Navigator Reserve. The symptoms you describe—rear end sagging, frequent and loud compressor operation, and a 'Service Air Suspension' message—strongly suggest a problem within the air suspension system.

Here are the most common causes and diagnostic steps:

  1. Air Leaks: This is the most frequent culprit. Over time, air springs (bags), air lines, or fittings can develop small leaks.

    • Diagnosis: Visually inspect the air springs for cracks or tears. You can also spray a soapy water solution on the air springs, lines, and connections (especially around the compressor and valve block) while the system is pressurized. Look for bubbles, which indicate a leak.
    • Impact: A leak causes the system to lose pressure, leading to sagging and overworking the compressor.

  2. Air Suspension Compressor Failure: If the compressor is running excessively and loudly, it might be failing or already damaged from overwork due to a leak.

    • Diagnosis: A failing compressor might struggle to reach the required pressure, or it could be making unusual grinding or rattling noises. If the system has a leak, the compressor will run more often, shortening its lifespan.
    • OBD Codes: Common codes related to compressor issues include C1A31 (Air Suspension Compressor Fault) or C1A20 (Pressure Sensor Fault) if the compressor isn't building enough pressure.

  3. Ride Height Sensor Malfunction: The system relies on height sensors to determine the correct ride height. A faulty sensor can send incorrect signals, causing the system to try and compensate unnecessarily or fail to adjust properly.

    • Diagnosis: While less common for sagging, a faulty sensor could contribute to erratic behavior.
    • OBD Codes: Look for codes like C1A27 (Ride Height Sensor Fault), often with a specific wheel indicated (e.g., C1A27-11 for Left Rear).

  4. Air Suspension Control Module (ASCM) or Valve Block Issues: The valve block directs air to and from the air springs. A faulty valve block can leak internally or fail to open/close properly. The ASCM controls the entire system.

    • Diagnosis: These are less common but can cause complex issues. A professional scan tool can often pinpoint issues with these components.

When to See a Shop: Given the intermittent warning message and the potential for multiple components to be involved, it's highly recommended to have a qualified technician inspect your vehicle. They have specialized diagnostic tools to read specific air suspension codes, perform system tests, and accurately pinpoint the source of the leak or component failure. Continuing to drive with a compromised air suspension can lead to further damage to the compressor or affect vehicle handling and safety.

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