check OEMCATS possibility

 

Also found Timbren GMRH2 we'd need to confirm the fit, down side is they're expensive!

 

Has anyone seen the message, "Device limits exceeded", from scan tool when trying to calibrate? When I run the Calibration, it shows in progress. I hear brief activity from the system, then 'click' and the error message is displayed. Both height sensors are new and working within normal ranges. One thing I did notice is that the Height Sensor Current is 16-17 mA. I see others indicate thiers is 21mA. Is mine out of spec?

I have access to a couple different tools (SnapOp, Autel, and Thinkcar) and getting same message. All these tools have the Special Functions and I can Depressurize System, but no matter what I do, it just gives me error on the calibration. I had used the SnapOn tool successfully a few years ago, so I know it did work at that time.

I have followed the instructions exactly. The D measure is 5 3/16".

The Calibration Learned is NO. Yet it will air up correclty when I start the truck.

Im just wanting to level the truck. The driver side is sitting an inch lower than passenger side.

 

ejsmall the message "Device limits exceeded" might be a bespoke message rather than GM, 16-17mA seems about right, this is the total current supplied by the ASCM +5V circuit, so it may depend on the type of sensor fitted, if you can read the L/R ride height voltages they should be find, incidentally what do they read? They should both be in the range 2.06-2.88V for calibration to be accepted.


For ref this is the GM procedure (note CH-47816 is a GM calibration block)

Tools Required
CH-47816 Suspension Position Calibration Blocks

Important: Before proceeding with the steps below, ensure:

• There are no stored diagnostic trouble codes stored in the ASCM.
• 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.

1. Raise the vehicle on a hoist.
2. Install the CH-47816 on to the LR and RR jounce bumper mounting cups.
3. Lower the vehicle off the hoist.
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 .
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.

 

Thanks oceanbrave. Im in line with everything in those instructions other than not having the blocks and instead using bottle jacks to support the truck for the correct D measurement. So frustrating.

 

what were the all important ride-height voltages?

 

Sorry, you did ask that. This is what I have with truck depressurized and supported for D measure.

 

I posted about mine a few years back but you would have to search to find it. I did find a couple of my notes and photos though. I did have a note that the sensor voltage should be between 2.06 and 2.88 volts for normal ride height which I think I found in the GM TIS system.

Below is a photo of mine I took of my Tech2 screen showing the values I had. I did the recalibration using jacks as well to set it at the correct and even height. Then deflated, calibrated, etc as the instructions oceanbrave showed above. No idea if this info will help you though...

 

Thanks mixman. Seems I'm within range on everything, so I'm baffled. Maybe I need to breakdown and get a Tech2. I look online and see they range from $400 to $1400. Looks like all different models and different connection equipment. I suspect a lot of stuff perhaps needed for different years and model compatibility. What is the bare minimum I need for my 03 H2?

 

My Tech2, as most everyones that spent less than $1000 is one of the many Chinese clone ones. The company I bought mine from was excellent and I know at least 3 others on here bought from the same place but that site now seems to be gone.... A friend of mine got one from Obd2Tool (dot com) and his was just fine and it was like $300. Its the first item under GM Scanner on their site. The more expensive version includes the hard case (which actually is very nice to have as it stores everything nicely).

In any case the basic unit with the software is really all you need. As far as I'm aware, 99% of the clone ones are running the final genuine GM software for them and work just fine for your H2 (and many other GM vehicles though like 2009 models). Maybe the Tech2 works better with the fairly obscure H2 air suspension module than the other brand tools? I cannot say for certain but I can say that the software on the Tech2 from GM was specifically made to work with the modules 100%.

One thing to note - most of them will also come with the TIS2000 software. That is the genuine GM software programming updates for various modules. Its a bit fiddly to get it running (ideally you want like a Windows 98 pc with a serial port) but it works great and has some updates for some of the H2 computer modules including the AS module (which does resolve some excessive running issues). Be aware though - if you have upgraded the compressor to the newer style dual pump version then do NOT attempt to update the AS module software, the update is specifically for the original single pump style compressor and if used on the newer style dual pump module it will brick it.