Hyundai Equus Air Suspension Issues Explained(+5 Pro Tips)

In this brief article, we are going to discuss the different Hyundai Equus Air Suspension problems, what the causes are, and their troubleshooting Tips.

What are the most common air suspension issues in a Hyundai Equus?

The most common Hyundai Equus suspension issues are:

  • Uneven Ride Height
  • Corner Sagging
  • Compressor not working
  • Tips on replacing Air Spring

Hyundai Equus Suspension Set-up

The Hyundai Equus is categorized as an executive Luxury sedan that was manufactured between 1999 and 2016. Developed jointly with Mitsubishi Motors, the Equus was marketed under the Mitsubishi product name Mitsubishi Proudia in certain geographies. The Second generation (from 2014) was sold under the product name Hyundai Centennial and Hyundai Genesis.

The Front suspension set-up has a EAS (Electronic Air Suspension) strut which is integrated with the damper in a Double-wishbone arrangement. The Upper and lower control arms are split.

The Rear suspension of the 5 Series is a 5-link independent suspension (lower control arm, Upper control arm front, Upper control arm rear, Trailing arm and a Toe control arm) with a Torsion bar & coil springs. 

The Electronically-Controlled Air Suspension (EAS) was introduced in the year 2009 in the second-generation Equus. The model also introduced CDC (Continuous Damping Control) where the Damper’s internal valving worked with a solenoid that changed damping depending on inputs from the 3 G-sensors (accelerometers) of the vehicle and ride height sensors.

The EAS System had an air reservoir tank located near the front bumper.

The Solenoid Valve block, located in front of the front-right wheel right next to the air compressor, distributes air to the 4 corners and also control exhausting of air.

Uneven Ride Height

  • One corner sits lower than the other at normal ride height
  • Air suspension works fine; no issues with raising and lowering at all 4 corners
  • Explained as seen on the 2011-2016 2nd Generation Equus and Hyundai Genesis

Root Causes:

  • Sometimes, due to road impacts, over time, the ride height sensors lose their reference ride height position.
  • In these situations, the sensors would need to be recalibrated 

Troubleshooting Uneven Ride Height: EAS Reset

  • The first thing is to park the vehicle on a level surface and measure and record the ride heights at all 4 corners. Once it is confirmed that there is a difference at one corner, you can proceed to the next step.
  • In Equus, it is a known issue that the Electronically-Controlled Air Suspension (EAS) ride height calibration does get disturbed and cause a ride height reduction
  • The remedy is to do a ‘Reset’ of the air suspension
  • This can be done by first disconnecting the battery negative terminal cable and contacting this negative cable with the positive terminal of the battery.
  • You may use a connecting wire if the negative terminal cable does not reach upto the battery positive terminal. Make sure that the battery negative terminal is not in touch with anything during the process. You could use plastic insulation for this purpose as well.
  • Once the battery contacting is done, start the vehicle and allow 2-3 minutes in order for the system to do a reset.
  • Observe the ride height at the corner that had an issue and confirm by measuring whether the height has improved as compared to the previously recorded value.
  • If not, repeat the process 2-3 times and see a gradual improvement in ride height.

Troubleshooting Uneven Ride Height: Calibration

  • If you have access to a Diagnostic Tool, plug it into the OBD II to access the Automatic Ride height sensor calibration function.
  • The system raises and lowers the suspension and now asks for the measured ride heights
  • Measure the ride heights using the references mentioned in the service instruction documentation
  • Enter these values in the interface
  • After entering the values, the suspension performs calibration and completes the exercise

Corner Sagging

  • Corner suspension loses ride height after parking
  • When pressing the ride height button height does not change; the car icon appears on the center display showing the car is at normal height.
  • Sometimes one corner suspension drops during driving
  • After dropping the corner rises but soon loses height again

Troubleshooting Corner Sagging: Air Leakage

  • If there is a loss of suspension height in spite of a properly working air compressor, then the air leakages could be the next thing to suspect.
  • Air leakage related suspension sagging generally is seen when the car is parked overnight and sometimes even over a period of days.
  • Air springs are known to wear out and crack at the rubber bellow surface gradually after accumulating mileage. They generally would last 70K to 80K miles depending on usage.
  • In a high mileage vehicle, the air springs would be the first place to check for leakages.
  • In the Diagnostic tool, use the “Air Filling/Venting Set-up” Inspection/Test to fill air into the system. Then spray springs with soap solution to check for leaking.
  • After spraying the soapy water solution, wait to see if there are white foam bubbles that stay at one spot even after wiping it with a finger.
  • In cases where the leak is major, you even hear a hissing noise coming from the leakage point and be able to locate it by ear.
  • Once you have confirmed that there indeed is a leak, the air spring has to be replaced. Read this section to know tips on how to easily replace your Hyundai Equus air spring.

Compressor not working

  • Suspension does not rise after sitting low
  • No noise of the compressor working

Check for Compressor Function

  • Use the diagnostic tool use the “Air Filling/Venting Set-up” Inspection/Test to fill air into the system by running the compressor
  • First, listen to see whether the compressor turns on 
  • If the compressor does not turn on there is a high probability that the compressor fuse might be blown
  • Check the compressor fuse (orange 40A fuse) within the fuse box located under the Left-side Engine bay and replace it
  • Once again, using the Diagnostic tool, use the “Air Filling/Venting Set-up” Inspection/Test . See whether you can hear the compressor working.
  • See whether the suspension raises. If it does not, then it means that the air springs are not getting the required lifting pressure from the compressor.
  • To find the reason, it would be useful to measure the pressure developed by the air compressor. Check this against the normal working pressure, which will be mentioned in the Service Instruction.
  • If the pressure is insufficient, then replace the compressor in your suspension system

Tips on Replacing the Air Springs on a Hyundai Equus

  • Before removing the air spring for replacement, be sure to relieve the air pressure from it at the valve block, which is located in the underbody near the rear bumper.
  • Relieve the left or right air spring valve by loosening the connector gradually. If this is done suddenly, then you could risk damaging the O-rings within the air connector fitting.
  • While replacing the Air Spring, be sure to cut off the portion of the line that was squeezed or stretched in the old fitting after disconnecting. The reason being that the old used portion  of the air line could crack and cause a potential leak.
  • Once more way to relieve/exhaust/vent out air is to use the diagnostic tool venting function

The venting can be done for either one section  of the EAS or for the entire EAS.

Pro-Tip:

  • Some aftermarket brand replacement bellows tend to give a higher service life as compare to the original OE spare part
  • Moreover, some aftermarket replacement parts also come with a lifetime warranty instead of a limited warranty offered by the manufacturer

Conclusion

In this brief article we have discussed the different Hyundai Equus Air Suspension problems, what the causes are, and Troubleshooting Tips.

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