Air Ride Diagnostics Q&A: What You Don’t Know Might Be the Missing Piece of the Diagnostic Puzzle - AutoSuccessOnline

Air Ride Diagnostics Q&A: What You Don’t Know Might Be the Missing Piece of the Diagnostic Puzzle

Both four-corner and two-corner air ride systems have sensors that measure ride height, pressure and other information to control the suspension. Why is this important? Knowing the basic architecture will help you find components quicker and carry out leak checks faster.

What type of system are you dealing with?

There are two types of air ride systems: four-corner and two-corner. BMW and other OEMs use air ride systems that have air shocks on just the rear axle. On the other hand, Mercedes-Benz, Jaguar and Land Rover use systems with air springs at all four corners.

Both systems have sensors that measure ride height, pressure and other information to control the suspension. Most systems also have active shocks and struts that can work with the air spring to control vehicle ride and suspension level.

Why is this important? Knowing the basic architecture will help you find components quicker and carry out leak checks faster.

How is the compressor connected?

Systems can differ in the way they use the compressor. Some systems from Lexus and Toyota pump air directly from the compressor to the air springs. Other systems control the air in the units using a reservoir. The compressor replenishes the reservoir and not the air springs.

If there is no reservoir, the compressor will typically run whenever an adjustment that requires an increase in pressure is requested. If there is a reservoir, the compressor will run only when the pressure is below a specific level and conditions like temperature and road noise are optimal.

Some vehicles can have multiple reservoirs to increase the air capacity. For example, certain Mercedes-Benz E-Class models with the Airmatic suspension can have up to three reservoirs.

Why is this important? How the system manages the air pressure in the air springs is critical to diagnosing the compressor.

What is the suspension designed to do?

Entry-level air ride systems are designed to keep the vehicle level when weight is added. More sophisticated systems will use air to improve ride quality and control the pitch and yaw of the vehicle when it is moving.

A sign of the complexity of the system corresponds to the number of its ride height sensors. Systems that alter the pressure in real time will have sensors at all four corners. Less complex systems will have one air line, one height sensor and one set of inlet and exhaust sensors per axle. Also, units that are actively tuning the system for road conditions will have accelerometers mounted near the front or rear axles.

Other indicators of the complexity of the system are the number of other modules connected to the air ride system. In some cases, the air ride system might communicate only with the ABS module. Some vehicles will have the air ride module connected to the CAN bus that communicates with the vehicle’s ABS, ECM and BCM.

Why is knowing this important? Knowing what you are dealing with is critical because air ride corrections occur for a variety of conditions. In addition, when a correction is carried out, the system checks the correction with the pressure and ride height sensors.

What is the system doing at startup?

On most air ride systems, when the ignition is turned on, the system performs a self-check and does a little housekeeping. The system may lift the vehicle to a higher-than-normal ride height and then trim to the correct height using the outlet or exhaust valves. On four-corner systems, the rear will typically raise first followed by the front. This can also help to flush condensation from the air springs.

If the vehicle has electronically adjustable dampening, the valves are typically actuated to the fully open and closed positions. This requires a continuity check to make sure there is no open, short or high resistance in the system.

Why is this important? Most air ride and chassis codes are set in the first minute after the car is started. The self-check ensures that all the sensors and solenoids are functioning. If the compressor runs too long or the pressure drops too much, the system might set a code.

What is the exhaust valve doing?

Exhaust valves on a compressor do more than just lower the suspension. Most systems will open the exhaust valve for less than a few seconds before the compressor is engaged to release air from the compression chamber, ensuring low-current draw during activation.

The exhaust valve also can be used to purge condensation in the compressor and lines. Certain systems might also purge the lines after the vehicle is turned off.

Why is this important? Next to the air springs and compressor, the most likely component to fail is the main exhaust valve mounted to the compressor. If the exhaust valve is leaking or is stuck shut, the system will have multiple failure symptoms.  IC

Callout:

Knowing the basic architecture of the air ride system will help you find components quicker and carry out leak checks faster.

You May Also Like

Mayhew Extends Pry Bar Line

The new 36” orange and 36” green handled pry bars are now available.

Mayhew Extends Dominator® Pro Pry Bar Product Line with the Addition of New, 36” Orange and Green Handled Pry Bars- Now Available

Mayhew Steel Products, Inc. (Mayhew Tools) has added two new pry bars to their long-standing Dominator Pro Pry Bar product line. The new tools, a 36” orange and 36” green handled pry bar, fill a void in the extensive product line comprised of multi-color and length options, the company said in a press release.

Schaeffler Partners with Transmission Service Group to Support Technical Education

Schaeffler will provide ATSG members with ongoing education and technical resources, including in-person and online training events.

The Good Fight Against a Rising Tide

Managing the recon operation to manage holding costs is a car dealer’s best offense against margin compression.

ocean waves stock
Autel Approved for Nissan Central Gateway Access

Nissan Central Gateway can access AutoAuth with registered users to perform complete diagnostics on select late-model Nissans.

autel-autoauth-nissan
Parts Rates for Warranty Reimbursement Could Be a Hidden Gem for Dealers

Parts rates are not a “set it and forget it” endeavor. Just like labor, they should be monitored and adjusted accordingly.

Parts Rates for Warranty Reimbursement Could Be a Hidden Gem for Dealers

Other Posts

Closing the Deal

A drive-thru car wash system is designed to meet the unique needs of automobile dealers, as well as other businesses that employ vehicle fleets.

Drive-thru car washes should be a first-choice technology option for fleet-wash operators.
Hunter Engineering Releases Alignment Coverage for Hundreds of Vehicles

The release covers brand-new records – those not yet in existence at the time of the previous release – as well as updates to existing records, covering OEM changes to existing vehicles, the company said.

Hunter Engineering Releases Alignment Coverage for Hundreds of Vehicles
Leveraging Tools as an Incentive to Recruit, Hire and Retain Service Technicians

Using tools as an incentive has emerged as a highly effective method for attracting new talent and, more importantly, retaining them.

Leveraging Tools as an Incentive to Recruit, Hire and Retain Service Technicians
ALI Lifting Points Guide Covers 20 Years of Data in Print or Online

Easily find OEM-recommended lifting points to properly lift cars, trucks and SUVs.

Easily find OEM-recommended lifting points to properly lift cars, trucks and SUVs.