Air Ride hard fault troubleshooting and forcing system to inflate

[billcu]

My CE has a hard fault, the check air ride message comes on right after start up.

Here's how I troubleshoot and manually inflated the airsprings. This might help people that don't have the wiring diagram.

The air ride module is located under the passenger side lower cowl kick panel.

The gray connector is the one with the compressor, vent valve, and solenoid outputs, unplug it and pull it down a bit for access to the pins.

I use jumper cables to run the positive and negative around to the passenger side area, I tape small wires to the battery clamps to use as test positive and ground supplies. I put a glove over the positive clamp to protect it from shorting to ground, be careful with the small positive wire, don't let it touch anything unintentionally.

First, I test the compressor circuit, pin 18 is the relay trigger, connect the ground wire to it and the compressor should run. Just let it run for a second to make sure it runs, as the solenoids are not open.

Next test the solenoids, pins 14, 15, 16, and 17. Connect the positive wire to each one, one at a time, you will hear each solenoid click.

Obviously, if one of these tests fails you need to look at the compressor relay, compressor, solenoid, or wires to these components.

One of my solenoids didn't click, I checked the connector it was a little corroded, I cleaned it up, it's ok now, one problem solved.

Once these checked out ok, to manually inflate the air ride, apply positive to the solenoid pins (I do both fronts and rears together if they are equally low) and then ground the relay trigger and the air ride should inflate.

You can check the vent valve as well, apply positive to pin 30 you should hear a click, then apply positive to one or 2 of the solenoids, they should vent.

Here are the pin numbers and wire colors:

Pin 18, dark blue with yellow stripe, compressor relay trigger, apply ground to activate.

Pin 14, light green with orange stripe, LF solenoid, apply positive to activate.

Pin 15, orange with red stripe, RF solenoid, apply positive to activate.

Pin 16, purple with light green stripe, LR solenoid, apply positive to activate.

Pin 17, light blue with black stripe, RR solenoid, apply positive to activate.

Pin 30, pink, vent valve, apply positive to activate.

My CE still has the hard fault (I ran out of time and light) but at least the air ride is fully inflated for further troubleshooting.

 

[billcu]

I finally got around to fixing this. It turns out the air ride module wasn't getting power from the power distribution box under the hood. I checked pin 1 and 21 on the black connector, and it showed 5 volts, but it should be 12 volts. I ran a jumper wire to it and it works fine again.

I've had wiring problems with this car before, I'm not sure why, the car runs great otherwise.

 

[DHowe303]

Thank you so much for your info Bill. I hope you can bear with me through this post. I just picked up a CE about a month ago, after wanting one of these since I was about 17 (24 now).
It's a little rough around the edges but it seems pretty clean for nearly 160k of work. I'd consider myself slightly above average when it comes to being mechanically inclined, currently I don't have any tools or a garage due to my circumstances of relocating for my job.
So I bought the car with the air ride completely non-functional, the guy who I bought it from had experience with the cars and had a dealership run a test, showing that a solenoid was stuck, telling the system to vent. At first it was the front, then he let it sit for a while and the rear did the same, never to come back up.
He told me that if he were to have kept it, he would've started by replacing the height sensors. I had a guy who runs a local shop do a diagnosis and he found it was the height control relay (I'm assuming the module in the interior, though I haven't pressed him on this, yet)
When I went to pick up the car, the front was sagging with the rear sitting as it should. A mechanic that worked at the shop (not the owner) said they felt there was a leak in the system, because they heard a venting noise, particularly from the passenger front.
Starting it up, the front rose and didn't fall after shutting it off twice.
Went on a 2hr journey, got a check air ride message on the interstate. When the journey concluded, I found the front sunk again. I assumed it was because the system lowered after it hit 70mph (which is what I believe the system is supposed to do) and just didn't pump back up.
Started the car back up, and the front rose again and held, even after shutting the car off and sitting. Got another check air message almost right after starting, and the front has been sunk since.
What do you think should be done next? A leak doesn't seem possible. Maybe there's a slow leak, but it wouldn't be acting like this if that were the case.

 

[billcu]

I wouldn't rule out an airspring leak yet, but I would go ahead and test the compressor and solenoids like I did in the post.

If they check out ok, I would go ahead and pump the front back up to parked height, 24.5" from the bottom of the wheel rim to the bottom of the fender arch. Once it's at the correct height, turn the air ride switch off in the trunk, on the left behind the little door in the trim.

Then, let it sit overnight and see if it leaks down again. If it doesn't leak, leave the switch off and go ahead and drive it around to see if it leaks down then.

If it does leak back down it's usually an airspring leak.

If it doesn't leak down, I'd check pins 1 and 21 on the black connector for 12 volts next.

 

[DHowe303]

I wouldn't rule out an airspring leak yet, but I would go ahead and test the compressor and solenoids like I did in the post.

If they check out ok, I would go ahead and pump the front back up to parked height, 24.5" from the bottom of the wheel rim to the bottom of the fender arch. Once it's at the correct height, turn the air ride switch off in the trunk, on the left behind the little door in the trim.

Then, let it sit overnight and see if it leaks down again. If it doesn't leak, leave the switch off and go ahead and drive it around to see if it leaks down then.

If it does leak back down it's usually an airspring leak.

If it doesn't leak down, I'd check pins 1 and 21 on the black connector for 12 volts next.

Sounds good, thanks Bill!

 

[Roadboss]

Bill
You should make this a sticky in the Suspension area, good stuff on your part