Lincoln Navigator & Ford Expedition Air Suspension Diagnosis & Troubleshooting

Owning a 2003 to 2006 Lincoln Navigator or Ford Expedition can come with its share of problems, and the air ride suspension is definitely one of the bigger headaches these vehicle owners face. We will cover different aspects of the air suspension for these vehicles, including how to diagnose and repair failed components.

One of the easiest ways to check for leaking air struts, springs, or solenoids is to shut off the air suspension via the air suspension switch, which is often located either in the trunk or on the right side of the passenger foot well, and leave the vehicle sitting overnight. If you find your Expedition or Navigator has lowered a few inches or more, your probably have a leak somewhere in your air suspension. Hunting it down is as simple as letting your vehicle raise to its factory height, and spraying down your air struts, springs and lines with soapy water. If you notice any consistent bubbling from any component, you can be sure you have sprung a leak.

Another common issue is the vehicle sections sitting at different heights, like the front sitting higher than the rear, or one side is lower than the other. This is a known issue, described in Ford’s Technical Service Bulletin 06-15-10, where the Height Level Sensors may disengage from the ball stud on the linkage arm. Ford recommends you do not reattach the level sensor, but purchase new linkage arms (part number 6L1Z-3D038-AA). This can be easily identified by looking in each wheel well and finding the linkage sensor either in front of or behind the strut. Inspect the sensor and ensure it is still attached to the ball joint and is not swinging freely. Alternatively, if you have a New Generation Star Tester (NGS) diagnostic tool, you can connect it to the data link connector and if you retrieve the diagnostic trouble codes C1725, air suspension front pneumatic failure, or C1726, air suspension rear pneumatic failure, you can be sure you have a height level sensor or linkage arm issue.

Before you perform any diagnostic with a NGS, make sure you do the following:

1)      Make sure all doors, the liftgate and the liftgate glass are closed. If any open door indicator lights are still illuminated with these closed, you have a door sensor issue, and need to correct it immediately before diagnosing your air suspension.

2)      Put the vehicle in park

3)      Do not engage the parking brake, or press the brake or accelerator pedal during the testing.

Known diagnostic trouble codes:

B1342 Air Suspension Control Module – This code indicates the air suspension control module needs to be replaced, which is located under the dash behind the throttle.

C1724 Air Suspension Height Sensor Power Circuit Failure – This code indicates there is an issue with air suspension height sensor, usually located between the number 5 frame crossmember and the panhard rod, and is always replaced as a whole unit.

C1725 Air Suspension Front Pneumatic Failure – This code indicates an air issue with the front of your suspension.

C1726 Air Suspension Rear Pneumatic Failure – This code indicates an air issue with the rear of your suspension.

C1760 Air Suspension Rear Height Sensor High Signal Circuit Failure – This code indicates an issue with the rear level sensors, either the sensors themselves failing, or dethatching from the ball joint holding them in place.

C1770 Air Suspension Vent Solenoid Output Circuit Failure – This code indicates the vent solenoid, located at the air compressor cylinder head has gone bad. This is usually replaced with air compressor pump as a whole unit.

C1790 Air Suspension LR Air Spring Solenoid Output Circuit Failure – This code indicates an issue with the solenoid at the rear driver side of your air strut.

C1795 Air Suspension RR Air Spring Solenoid Output Circuit Failure – this code indicates an issue with the solenoid at the rear passenger side of your air strut.

C1830 Air Suspension Compressor Relay Circuit Failure – This code often indicates the air suspension relay needs to be replace, which is located on the air compressor bracket, just above the attachment to the radiator support on the passenger side. The Ford part number for this relay is F3LZ-2C013-B.

This information should help identify most air suspension issues before they become a real problem. Suncore strongly recommends proper inspection and maintenance of your air suspension components to save yourself from costly repairs and the headaches that come along with them.