The right ride hight sensor broke so I purchased 2 new ones for both sides and put them on. But now when I start the truck it won’t go to the normal ride hight. So I purchased a autel scanner to calibrate the ride hight. But when I press calibrate it says device limit reached and I checked everything I could think of, my volts on my sensors are 2.35 and 2.34
so I think those are good, but it still won’t calibrate. The only thing I can think to do is purchase a tech 2 scanner

 

try jacking the rear of the body from maybe the tow hitch receiver to ride hight with the wheels on the ground then try recalibrating

 

Okay I put a jack stand on the back where the tow hitch sits. And it still won’t calibrate

 

If I remember correctly when I did this procedure on my 06 I used a set of calibration blocks that went over the bump stops that set things to a specific height when going through the process. I believe part of the reason these are used are so the resistance values of the height sensors can be reset once the axle is sitting hard on the blocks against the frame. I couldn't get the calibration set right until I got the blocks. I was told later you could fool the calibration with a properly placed jack or blocks on each side of the axle on the bump stops.

 

With the rear suspension mechanically set at the correct height, check the sensor voltage readings on the Tech2

Can't recall exactly the range limits off-hand, it's something like 2.5V +/- 0.5V with 2.5V being the midpoint.

If voltages are outside the range calibration will fail.

Check the service manual for exact range limits and correct calibration procedure.

 

Check today's parallel post on a similar subject.
https://www.hummerforums.com/forum/h...n-issue-47032/

 

Thanks Ocean for the help. The only thing I can think of is to purchase a tech 2, I have a Autel scanner and I don’t think it works I can depressurize the truck but not calibrate the ride hight. So that’s the next option

 

Well I got a tech 2 scanner and set it at the correct hight. And the sensors were reading at 2.5 volts and calibrated it and then started it and it rises up to maximum hight but doesn’t lower back down to the ride hight. I have tried calibrating multiple times since then and still the same problem the tech 2 says, ride hight learned but it won’t level at that hight

 

@Phsewell3

Below is the GM Suspension Position Calibration for an 03, one must assume GM dealerships follow this exact procedure so therefore it must work. Any step missed-out may mean the algorithm may fail.

Tools Required
CH-47816 Suspension Position Calibration Blocks - You probably wont have so the H2 will need to be mechanically set with the bags deflated

Important: Before proceeding with the steps below, ensure:

• There are no stored diagnostic trouble codes stored in the ASCM. - this could be important !
• The vehicle is on level ground.
• There are no occupants in the vehicle.
• The tire pressures are at the recommended kPa/psi.
• All vehicle doors are closed. - could also be important

1. Raise the vehicle on a hoist.
2. Install the CH-47816 on to the LR and RR jounce bumper mounting cups. - something you need arrange/improvise
3. Lower the vehicle off the hoist. - now the vehicle has something to rest on after being depressurized in the step below.
4. Depressurize the air suspension system in order to allow the full rear weight of the vehicle to rest on the blocks and rear axle. Refer to Air Suspension Depressurization (see below) - again this step could be key as the cycle will begin with low pressure in the bags
5. Turn ON the ignition, with the engine OFF.
6. Install a scan tool.
7. With the scan tool select Chassis.
8. Select Air Suspension.
9. Select Special Functions.
10. Select Trim Height Calibration and press the Enter key. The scan tool will flash Calibration In Progress, then display Calibration Complete.
11. Press the Exit key.
12. Pressurize the air suspension system until the rear weight of the vehicle is lifted of the blocks. Refer to Air Suspension Pressurization .
13. Remove the CH-47816 .
14. Ensure all vehicle doors are closed. Cycle the ignition switch OFF then start and run the engine for 2 minutes to allow the vehicle to level at the designed ride height.
15. After ensuring all vehicles doors are closed, use the scan tool to raise and lower the vehicle by commanding the extended ride height switch special function each time to verify the air suspension system is functioning properly.

Air Suspension Depressurization
To depressurize the Air Suspension System install the scan tool with key in the on position. Go to the special functions menu of the Air Suspension section and follow the on screen directions. The suspension will deflate the air springs until the suspension is on the jounce bumpers.

 

I followed all the steps ensuring I let all the air out of the system and all the doors are closed and the DTC
codes are clear and a charger hooked up to the battery but still when I start the hummer after calibration it airs up to its maximum hight

I have bo clue what to do now I have tried everything I can think of