The Discovery 4 utilises the modern airbag suspension system. EAS (Electronic Air Suspension) allows the user to control the air springs by inflating and deflating according to the terrain and conditions.
This Disco was booked in with an air suspension problem. Our technicians found that the fault code indicated an issue on the offside rear height sensor. We checked height sensor was working, and followed up with an investigation to the wiring harness back to the nearside rear multi plug. On inspection we found that found three wires had corroded through.
Air Suspension Fault
Air suspension in modern cars has replaced traditional coiled steel springs (or leaf suspension). Air suspension is powered by an air pump or compressor and allows improved handling of your off road vehicle (and can make it easier to access too!). If you want to take your Discovery off road, the driver just needs to increase the ride height, and for a smooth drive with improved handling on road, the driver can simply lower the drive height. The reduced vibration that air suspension provides also results in added the benefit of less wear and tear on the suspension system and components, and the ability to adjust suspension to road driving conditions and load can also help improve fuel economy.
With more components there in as an increase in mechanical issues and areas of diagnosis and when you experience a suspension fault
Air suspension components comprise of:
- Air bags
- Ride Height sensors
- Air Struts
- Air Springs
- Air Suspension Compressors
- Storage tank
- Air Suspension Solenoid Valve blocks
- Electronic Control Unit
Common Signs Of Air Suspension Fault
- Suspension fault error codes
- Individual sensors not receiving the right voltage
- Air suspension rising slowly
- Air suspension rises noisily
- Vehicle riding lower than normal
- Compressor wont turn on
- Vehicle sagging on one side
Common Air Suspension Faults
Air Bag Fault
Over time air bags can deteriorate and perish causing leaks. If this happens the air bag is unable to fully inflate.
Height Sensor Fault
Due to the amount of wear and tear a typical 4×4 endures it is unsurprising that sometimes sensors can become damaged when they are exposed to rough terrain. If there is a fault with the height sensor the ECU will be unable to determine whether to fill or release air from the air bags and can result in the suspension becoming stuck at one height or even sag. On this Discovery 4 the wiring had become corroded over time (and use!) which caused the height sensor to fail.
Solenoid Valve Block Fault
Valve blocks distribute air from the compressor to air springs (or struts). The valve block o-rings can rot and corrode over time resulting in damage to the solenoids electrical components through moisture via air leaks. The leaks can also cause the compressor to be overworked due to low pressure.
Electronic Control Unit
A fault with the ECU can be as simple as an issue with loose or deteriorated wiring which can happen over time. If you experience an ECU fault it is advisable to contact a professional with the appropriate diagnostic equipment to identify the issue.
At Alton 4×4 our team have the experience and knowledge to diagnose an issue at the early stages which avoids unnecessary costs. If you have a suspension issue with your off roader get in touch today on 01420 259015
Diagnose it first time every time.