Hummer H2 Air Suspension Problems and Repair Options
The Hummer H2, produced between 2002 and 2009, is a rugged and imposing SUV known for its iconic looks and technical sophistication. Although it only came in a single body style and trim level, there were several add-on packages to choose from, including the addition of a self-leveling rear suspension system in the form of the SB2 five-link air-suspension system. The Hummer H2 air suspension is designed to offer a comfortable and adaptable ride.
As with all vehicles with air suspensions, Hummer H2 rear air suspension problems are a common occurrence. The first place to start is knowing how to inspect your Hummer H2 air suspension and what to look for when diagnosing problems.
10 Signs of Hummer H2 Air Suspension Problems
Ordinarily, the Hummer H2 air suspension helps to improve ride smoothness and supports the rear weight of the vehicle. However, over time, the system is prone to developing problems that can affect ride comfort, handling and overall performance. If this is happening to your vehicle, it may be showing apparent or subtle signs. The following are some common signs and symptoms of Hummer H2 air suspension problems across the various model years.
1. Warning Light On
The most obvious sign that you are experiencing Hummer H2 suspension problems is if the “Service Air Suspension” message appears on your Driver Information Center (DIC). In this instance, it is best to restart the vehicle to see whether the warning persists because it may simply be a minor system fault. However, if the warning light is not showing and you spot any other signs of rear air suspension problems, consider visiting your mechanic.
2. Overrunning Compressor
If your Hummer air suspension compressor keeps running extensively once there is enough — or once there should be enough — air in the system, thoroughly check your suspension system. If there is an issue, it can damage the compressor and affect other suspension parts. The likely cause may be an air leak if the air springs are not inflating. Thankfully, detecting a leak in air ride suspension is a fairly straightforward process.
3. Compressor Runs After Hummer Is Turned off
Another issue can be that your compressor continues to run even after the engine is shut off. The likely reason for this occurring is that the relay has blown. Once the relay is out of commission, your compressor has nothing telling it when to turn on and off.
4. Inactive Compressor
A related potential problem may be that once you turn on your ignition and close all the doors, including the rear hatch, your air suspension compressor does not activate, even if switched on manually. This could be a minor issue such as a faulty fuse or a more substantial one like your compressor failing.
5. Sagging Ride Height
If your Hummer H2 is squatting at the rear or you notice a difference in height between the left and right back rear suspension, double-check the vehicle's stance once on level ground to ensure it is a suspension issue.
6. Ride Settings No Longer Function
The Hummer H2's Electronically Controlled Air Suspension (ECAS) system features an Extended Ride Height (ERH) function that allows you to raise the rear body area of the Hummer over the standard ride height. This allows for excellent ground clearance and increased off-road mobility. However, if your Hummer will not permit this function — provided you are not traveling too fast for this setting — then it is likely that it has minor leaks the compressor cannot keep up with during full extension.
7. Noisier Ride
The Hummer H2 is, by design, not a quiet vehicle, so it can be tricky to pick up on abnormal sounds. However, if you are familiar with your Hummer, you'll want to listen for any peculiar knocks, clunks or hisses.
8. Rougher and Bouncier Ride
While riding on level urban roads, you might not immediately notice initial air suspension deterioration. If you suspect any issues, take your vehicle out on slightly rougher roads and assess whether the air suspension feels less smooth. Deteriorating ride quality on less consistent surfaces may be a sign of components beginning to fail.
9. Sloppy Handling
Pay attention to how your Hummer handles, especially through corners, over bumps or during terrain changes. The rear will feel heavier and the weight will likely not shift optimally. Additionally, you may experience suspension bottoming. Over time, this will also lead to other symptoms such as badly cupped tires, shaking, and steering wheel vibration or shimmy. It is important to note that alignment issues and damaged or unbalanced tires or wheels can also cause steering vibration.
10. Poor Braking
For bigger and faster vehicles, the suspension plays an even more significant part in absorbing some of the braking force than with slower and smaller cars. If your suspension functions optimally, it will typically support the brake calipers, ensuring safer braking. However, when your Hummer H2 air suspension starts to fail, your stopping distance will increase and your braking will be less smooth.
Hummer H2 Front Suspension Problems
Faults in the independent front suspension (IFS) or front torsion bar suspension can lead to problems in both the front and the rear suspension systems. Below are common signs that your front suspension is experiencing problems and requires inspection:
- Nose diving
- Uneven tire wear
- Vibration on your steering wheel
- Difficult steering
- Excessive bounce
- Vehicle pulling to one side
Parts That Make up an H2 Air Suspension System
There are benefits and drawbacks to air suspension systems, most of which are attributed to the fact that air suspension systems are complex. The system involves several components performing various duties. The rubber air springs afford you a soft, smooth ride regardless of the terrain with the aid of these parts and assemblies:
- Rubber air spring bags (or bellows): Cushion and support the vehicle weight using pressurized air.
- Solenoid valve blocks: Regulate the air pressure within each air spring.
- Air plumbing lines: Carry the air to the air springs to adjust the vehicle height.
- O-rings: Ensure that air plumbing line connections are adequately sealed.
- Air suspension control module: Gathers information from ride height sensors and other components to control the inflating and deflating of the air springs to maintain the correct vehicle ride height.
- Height sensors: Measure the vehicle height and constantly transmit this information to the control module to ensure speedy height correction.
- Air compressor: Keeps the air spring bags inflated by producing pressurized air and sending it through the plumbing lines.
- Air dryer: Prevents moisture building up inside the air suspension components by keeping the system dry.
- Shock absorbers: Work with the spring bags to dampen vibrations and deliver a smoother journey.
Overload and Overheat Function
Before examining the causes of your H2's air suspension problems, it's worth knowing about the overload and overheat function, a built-in mechanism designed to protect the air suspension components. If you have loaded up your Hummer H2, but the rear suspension remains lowered, it might be due to the axle load exceeding the Gross Axle Weight Rating (GAWR). This has nothing to do with a compressor fault or leaks in the suspension system, but is instead a means of protecting the system from damage.
Causes of H2 Suspension Problems
In addition to what signs to look for, you must also understand the likely causes of air suspension problems. A key component in air suspension systems is identifying the symptoms of leaking air and making necessary fixes or replacements. If you encounter any of the following primary H2 suspension problems, it's best to have a qualified mechanic inspect your vehicle.
1. Air Spring Leaks and Failure
The most common cause of leaking is wear over time as the components work to inflate and deflate the rubber air springs repeatedly. The rubber eventually incurs dry rot, and tiny cracks lead to leaks. Initially, the effects may be insignificant, but as the leaks worsen, the air compressor will be forced to work harder and harder. Ultimately, it will shut off if it overheats. At this point, it will be clear that the damage is extensive, as the compressor can no longer generate pressurized air fast enough to keep the vehicle supported.
2. Air Plumbing Line Damage and Leaks
Several small air pipes run along your air suspension system to connect the air springs with the other system components, most notably the compressor. Over time, as the suspension moves, the pipes deteriorate and get damaged, leading to air leaks. If the entire rear sags, the leak is closer to the compressor, while one corner sagging can mean a line near that air spring bag is leaking.
3. Air Suspension Compressor Failure
Over time, an air compressor will deteriorate and start acting up, leading to eventual failure at the end of its life span. However, failure may also be due to extensive use and stress caused by other components breaking. For instance, if the air springs start leaking, it will cause the compressor to work overtime and result in a shorter service life.
If you have a 2003 or 2004 model Hummer H2, your vehicle is likely fitted with a single-stage compressor — if it has not already been changed, you might consider upgrading to a dual-stage compressor, as seen in the 2005 to 2009 models.
4. Height Sensor Failure
A sign that one of your suspension leveling sensors has failed is that your Hummer sags to one side while the other airbag still inflates as expected. To test this, locate the sensor connected to the frame rails behind the tire in the wheel well. You'll want to start the vehicle and then manually shift the sensor up or down.
If it is merely a mechanism failure and the sensors still work, this movement should register as changes in ride height, which will cause the air compressor to turn on and fill the air springs.
5. Air Dryer
The air dryer is responsible for eliminating the moisture in the air and keeping your suspension system free of any liquid buildup. If your air dryer fails, you will likely notice it once a level of damage has occurred. Moisture will build up on metal components, causing them to rust and eventually resulting in leaking. Additionally, the added moisture will start to impact the efficiency of the system's leveling capabilities and lead to sagging.
6. Suspension Relay
The electronically controlled air suspension relay is wired to the pressure switch and is responsible for turning the compressor on and off. If this component is faulty or fails, your compressor will stay on far longer than it should and may not shut off at all. A temporary fix for this is to remove the relay fuse and turn off the compressor until you can replace the component.
Resetting Your Hummer H2 Air Suspension
The “Service Air Suspension” warning may appear on the DIC even though the system is in working order. In this case, your Hummer H2's air suspension reset function should clear the error. Additionally, if you're experiencing improper function of your air suspension system, resetting it may correct the fault once the system restarts.
This measure may resolve minor system errors, but it is not a viable solution for long-term correction. To reset your Hummer H2 air suspension, you can turn off the air compressor via these steps:
- Unload any heavy objects in the vehicle.
- Locate the air suspension inflator switch in the trunk or the inside rear area of the Hummer.
- Switch the air suspension off, taking care to ensure the inflator light is off.
- Allow the air spring bags to release all the air.
- Turn the air suspension back on after a few minutes.
- Take the Hummer for a drive and assess whether the issue is resolved — remember to test the ERH as well.
Alternatively, you can disconnect the vehicle battery:
- Ensure the ignition is turned off and the engine is not running.
- Remove the negative terminal from the battery.
- Allow a few minutes before reconnecting the terminal to the battery.
- Check to see if any warning messages have cleared.
- Drive your Hummer H2 and see if the issue is resolved.
When problems with the air suspension of Hummer H2 occur and your system eventually fails, there are three primary options to return your beloved vehicle to optimal driving condition. You can fit original equipment parts, choose to use aftermarket parts, or save time and money with a conversion kit.
1. Fitting Original Equipment Parts
The initial thought might be to install Hummer H2 air suspension original equipment (OE) parts. The trouble with this option is that certain OE parts are no longer available — plus, air suspension repairs and replacements are expensive, whether you hope to replace individual components or the entire system.
The benefit of OEM equipment is that it will restore your Hummer to its original functionality. Still, the cost of parts and labor will be considerable. You'll need to decide whether that investment is worthwhile for a vehicle that will experience further repair costs as it ages.
2. Opting for Aftermarket Parts
In many cases, if you wish to retain your air suspension, you must choose aftermarket parts that may offer inferior performance and quality compared to your OE units. Yes, you are likely to save on part costs, but the intricacy of an air suspension system means extensive labor. What is more, fitting these components yourself requires substantial knowledge of how the systems work.
Eventually, these parts will experience the same wear as your previous installation, meaning you will need to incur those high costs again.
3. Converting to Coil Springs
A viable and cost-effective suspension investment is replacing the rubber air springs with durable coil springs. In most cases, you can convert your entire suspension to coil springs for the cost of a single air suspension strut. The ride will be slightly stiffer since you no longer have air-cushioned suspension, but it will still offer ample comfort along with the benefits of reliability and avoiding the headache of replacing numerous air suspension components.
There are several advantages to using a Hummer H2 air suspension conversion kit, including the ability to eliminate any front suspension problems. Converting to coil springs offers five main benefits:
- Reliability and durability
- Simplicity and avoiding reliance on electronics
- Easy installation with no modifications required
- Light fix module to disable the warning light on the dash without requiring convoluted disabling methods
Shop Strutmasters Hummer H2 Conversion Kits
Are you ready to simplify your Hummer H2's suspension system and leave costly and unreliable air suspension systems behind? Strutmasters Hummer H2 suspension conversion kit options provide a simplistic and reliable alternative to your OE air suspension system. We also offer a warranty on our Strutmaster-branded products so you can purchase our solutions with confidence.
Strutmasters has been the leading name in the suspension conversion kit industry since 1999, and we understand the importance of both product and service quality. That's why we offer ASE-certified technical support to assist you with your conversion process. If you have any queries beyond our frequently asked questions, please call 866-597-2397 or complete our contact form to connect with our team.
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