Does air ride scare you? Would you prefer to sell a conversion kit rather than diagnose an air ride code or light? You are not alone. On the surface, these systems can seem complex when compared to metal springs. But, once you understand how the system senses the vehicle’s state and how the air pressure is managed, air ride diagnostics and service won’t seem so overwhelming.
What Happens At Startup?
Almost every air ride vehicle has a self-diagnostic process that occurs during startup. Depending on the vehicle, this can include checking sensor inputs, valve actuation tests and pressure checks. Some systems will open the exhaust valve to remove moisture.
The system will trim the vehicle for the specified static ride height as part of the startup diagnostic process. If the trim process uses too much pressure or compressor time, it could be the sign of a leak and might set a code.
Where Are The DTCs Stored?
The module that controls the air ride system typically stores the code. Advanced four-corner systems typically have a dedicated module. Some systems may use the body control module. But, it might be critical to understanding how the module communicates with other modules. Most air ride systems need information from the ambient air temperature sensor (or MAF sensor), vehicle speed and other inputs ranging from stability control to door switches.
What Happens When The Suspension Goes Into A Service Or Workshop Mode?
Rather than letting the vehicle rest on the bump stops with the compressor running non-stop, the air ride system will disable or set the suspension at a safe pressure. The vehicle will then alert the driver with an instrument panel warning. Some vehicles limit the speed of the vehicle until the problem is resolved.
Why Does The Compressor Time Out?
One of the jobs the system’s embedded logic can perform is to save the compressor from destroying itself. If a system leaks, the compressor will have to work harder to keep the vehicle at the same ride height. Excess heat can cause premature wear of the piston rings and, if the leak goes unchecked, it can cause the compressor to fail.
How Does The System Measure The Temp Of The Compressor?
Most pumps do not have a thermocouple to measure the exact temperature. The computer module controlling the pump keeps track of how long the compressor has run and how long the correction should take. If a correction to ride height takes too long, the system knows that the compressor could overheat, sets a code and then disables the pump before it is damaged.
