How to Diagnose Air Suspension Problems - GM Vehicles

What's up, guys? I'm Andy from 1A Auto. In this video, I'm going to give you some tips on how to check if your air ride system is not working in your GM vehicle. This happens to be a 2009 Chevy Suburban. Other GM vehicles will have a similar system. If you need parts for your vehicle, click the link in the description, and head over to 1AAuto.com.

All right. I'm just going to turn the key on, and what we're listening for is a pump coming on over here. I hear some clicking right there. That is the air ride pump, the air compressor. It's pumping, which is always a good sign, the fact that the air pump works because you know that the electrical circuits to the air pump are working. We don't know if the air system is leaking at all or anything, but at least it's a good sign that the pump works.

All right, we have our scan tool hooked up to the vehicle with the key on. This is a wireless scan tool, which is nice, so we could be over here working while it's hooked up. We have a GM vehicle. Now, we can do an automatic search. Is that the correct VIN? Yes. You can always double check. Yep. It's a Chevy Suburban, 2009.

All right. Now I want to ... System selection. Let's see. So, this asks whether it's an automatic HVAC or a manual. That's your heating and air conditioning. If you take a quick look at the HVAC control unit, if there's a screen on it and it shows different values on the screen, then it's an auto. If it was just a manual, then you would click Manual.

So, we'll click Auto, and this is the GVW. If you don't know it, you can always look on the door. You can find that right here. Let's see, the total GVW is 7400 pounds, so, it's under 8600 pounds. Then you want to look for the RPOs. Those are normally in the glove box. We can see if it has a Z95 or without Z95. This vehicle does not have Z95, so you click Without Z95.

Then we're looking for some ... ECM, engine control transmission, fuel pump, transfer case ... Electronic suspension control. That's what we're looking for. Click on that. Now, let's read fault codes. All right. This is the code that we have in this system right now, which this code actually isn't that bad. For this, this is a device voltage code. What happened on this vehicle was the battery died, and with the voltage being too low when you go to start the vehicle, a lot of the modules go all crazy because they don't know what to do, because they only have nine volts in them, or whatever.

That code has nothing to do with the air ride system. At this point, all we have to do is clear the code. So, we can go back out of here, clear fault codes. Are you sure? Click Yes. It's been cleared out. We could always go back and see if we have any other codes, but we could drive this around and see if anything comes back, but everything appears to be working fine.

Let's see if we can read any data. Read data stream. All right. Okay. This is kind of cool. So, we can check the rear position sensor. Left rear, right rear, let's take a look at those. So, those are the values right now. The vehicle is lifted up a little bit off the ground. Let me go lower the vehicle and see what these values do. All right. I guess it was all the way down. Let me raise the vehicle. And see, the values changed when we raised up the vehicle. We can lower the vehicle again, and it shows the voltage changing, so we know those sensors are working properly.

All right. Now we're going to test the air ride system. We're going to turn the key on and we're going to load up the back of the vehicle with some weight. We want to see when the weight is loaded up, it's going to bring the vehicle down a little bit, and then the air ride system should kick on, add some pressure, and then bring the vehicle back up to a certain level. Performing that test, we at least know the pump is working and the level sensors are doing their job properly. So, that's a good first step. If your pump's not working, you might want to check for fuses and see if the fuses are blown. Then also check it up in the air.

With the vehicle up in the air, what we're going to do is look at the pump. Now, the pump module is right here. This is where the pump is, and the lines connect to this, and also the electrical connector connects to this right there. Now, what you want to pay close attention to, a lot of these older pumps, they're aluminum, and they will corrode right here, and you'll actually see the pump splitting. If that's the case, then your pump is bad and you're going to need a new pump.

Well, we can look at the electrical connector. Now, this is going to be secured on the top of the pump. What you can do is disconnect this. You want to look in there and on both sides and make sure there's no green, no corrosion on the terminals, which this, these terminals, look good. This terminal's been replaced before. So, that's a good thing to check.

Another thing about this air suspension compressor, this whole unit, generally you replace it as a whole and you don't get individual components. So if you have a code for the exhaust valve that is attached to this, or if there's a pressure sensor in there that you got a code for, you replace the whole thing.

Now what you want to do is check the air bags up on the actual shock. Make sure there's some air in them. A lot of times if this looks really flat, then the pump's not doing its job either. If your pump is running and it's still flat, then you have a leak somewhere, whether it be the lines are leaking or whether the shocks themselves are leaking. What you can do with the shock side, you can spray a little bit of soapy water on the shock and sometimes you'll see some air bubbles. A lot of times, these shocks, over time, will split, and especially if the pump goes bad, then you will find that the shocks, because there's no air in them going down the road, it's going to cause them to wear out a lot quicker. So, if you neglect replacing the pump, that's going to cause the shocks to go faster.

On the flip side, if the shock goes and the pump is always running, it runs continuously, so you're going down the road and you just keep hearing this pump noise, that's going to burn the pump out. Basically the two systems will kill each other, so, it's a good idea to address them as soon as possible.

Another component that can give you some issues is the electronic suspension control module. That's located right here above the spare tire on this vehicle. Some vehicles, it might be on the side wall, I mean, on the frame in a different location. But right there, if you see a lot of corrosion in there ... There is a good amount on this one, but it is working and we're able to talk to it with the scan tool, so that's working right now. But that could give you some problems also. Check the connectors on those, because if a connector gets corrosion in it, that could cause some issues.

Here is one of the level sensors right here. That's connected with this little bar. It looks like a dog bone. You want to make sure that's not broken. If that's broken, that can cause your pump to run for too long and burn the pump out, so check that, and make sure the connector is good. Connector's right there. And there's one on this side, and there should be one on the other side as well. Just double check those, make sure those are working. A lot of times if you have a bad sensor, it may set a code. But then again, if the sensor is off a little bit, it may not set a code, so that could be one of your issues.

These are the air lines, so these come off the pump or the compressor, and they go out to the individual shocks. So, these are just in the rear. They're not in the front of the vehicle. For front of the vehicle, the suspension is electronically controlled. You also have these sensors that are connected to the top of the shocks, so you could get a code for the sensor on the shock themselves.

We started out with that scan tool to check the system out. If you would like that scan tool, we sell that on our website at 1AAuto.com. The link will be down in description. If you don't have a scan tool, you can check out manually all the systems that we tested, and if they all pass, then your system's working properly.

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