Air ride leveling issue

[TokyoTux]

Hey gang,

I just replaced all 4 corners of my 2016 Yukon Denali with magneride, including the compressor. The rears I did GM genuine ($880 from rock auto). The compressor i got was aftermarket, it runs when I start the vehicle, the typical self test. I just connected my 23ft RV and she didn't self level, frankly I could use some guidance on what to check and whatnot. I did try searching but after 10 minutes gave up. Thanks and looking forward to the responses.

 

[Joseph Garcia]

Did you run the Automatic Level Control (ALC) procedure with a quality bi-directional scanner after replacing the shocks? This is not usually required, but given that your truck's compressor is not lifting the back end (please confirm that the compressor comes on after hooking up the trailer, in an attempt to raise the back end), I'd say that it is worth a try.

Also, if you have a quality bi-directional scanner, you can troubleshoot this function, and you'll have a good chance at getting to the root of the issue.

 

[TokyoTux]

Thanks Joseph

I didn't, and lack access to that tool. Any recommendations? I'm in Maine.

Before I changed the rear shocks I swapped the compressor last week as mine totally died, not even a self check. After swapping, the self check would work but still no self leveling. I replaced the shocks because they had 150k miles on them. I think the issue existed prior. Not sure where to start. I looked at fuses, they seem ok (assuming I inspected the right ones). Claude said to check or replace the relay but I've yet to identify where the relay is.

 

[Joseph Garcia]

When the compressor kicks in on startup, do the rear shock bladders stiffen up, meaning that there is positive air pressure in them? That startup sequence will bleed the air pressure and then re-pressurize the shocks.

 

[TokyoTux]

I've got an update...

I purchased an Autel MK808, it shows v0.0 for sensor voltage - not sure if there's an issue or if the Autel can't read them?

I put in a factory GMC compressor and tried my RV again. It fires up the compressor but I dont see it adjust the height much, compressor runs maybe 5 to 10 seconds and then stops. I did buy arnott branded ride height sensors, should I install those ? There's nothing left after lol.

 

[Joseph Garcia]

I've got an update...

I purchased an Autel MK808, it shows v0.0 for sensor voltage - not sure if there's an issue or if the Autel can't read them?

I put in a factory GMC compressor and tried my RV again. It fires up the compressor but I dont see it adjust the height much, compressor runs maybe 5 to 10 seconds and then stops. I did buy arnott branded ride height sensors, should I install those ? There's nothing left after lol.

The 5-10 second compressor activation at startup is normal, as it is a self-test of the air system. You should be able to read all 4 height sensors individually. What are the individual voltages? If the system is operating correctly, you should see positive voltages at each sensor, and they should be relative close to each other.

 

[TokyoTux]

I think sensors are good... I'll hook things back up tomorrow and do a full hookup test with the tool. The attached was while unloaded, could see the voltage fluctuate a little as I moved about the driveway.