Question about the ERH (Extended Ride Height) function.

Mine appears to be stuck on, the light is on the backend is raised. When I pushed the button nothing happens. it also does not disengage over 40mph. Any ideas on what I need to look at?

 

Sorry not sure why white text.Question about the ERH (Extended Ride Height) function.

Mine appears to be stuck on, the light is on the backend is raised. When I pushed the button nothing happens. it also does not disengage over 40mph. Any ideas on what I need to look at?

 

Well that should not happen obviously. Only a couple of things I can think that would cause this behavior. One - I believe the BCM (body control module) communicates vehicle speed and requests via the dash button to raise the rear to the AS (Active Suspension) module. If for some reason the rear was raised then the BCM subsequently loses the ability to communicate with the AS module then I can see it possibly being stuck in the raised position. The only other thing I can think is that the AS module itself has developed a problem.

What I'd try first. Disconnect the battery overnight. See if things start communicating against after a nice bit of time without any sort of power.
Next I'd try unplugging and replugging in the AS module which is on the edge of the compressor shelf under the rear. Fairly easy to see it, but awkward to reach but maybe a bad connection there.

 

Awesome, I will do both.

Just picked it up from the dealer as it says Service 4x4 and they said no codes or faults. They can't figure out how to remove warning. I do have an Autel scanner I can plugin but last time I did nothing came up and I could not solve this or the Service 4x4 warning.

 

To add to MixManSC's suggestions, it could be the exhaust valve, either blocked or inoperative (air can't escape)

I seem to recall someone having a similar issue recently (can't find the post to hand)

 

That Autel scanner will not be able to communicate or read codes on certain modules like the AS module. Only a GM Tech2 or MDI can deal with those...

A dealer that cannot figure out a service 4WD message means you need to find a competent dealer as they are idiots.

Service 4WD is most often the actuator on the side of the transfer case being worn or sticking from lack of use but could also be the 4WD selector button panel, the transfer case itself (worst case). If the Service 4WD message is displayed, then none of the 4WD Lock modes can be used in any way.

 

Left Negative terminal off all night, no change.

Looked underneath and saw the shelf with the pump and a few control boxes, I will unplug those this evening.

 

My air compressor in the back stopped working also, the light on the button is on however it doesn't operate when pressed.

 

What model year is yours?

 

Dang, otherwise the Autel reader has been great on my other cars.

I already replaced the encoder motor, I was getting the flashing lights. Now it shifts into 4 Lock modes.

Took it to a Chevy/GM dealership as they said they were familiar but they couldn't tell me why the Service 4WD light was on and said no codes were being thrown and everything was operating as it should.