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View Full Version : Air suspsension light please help


fbodyguy99@hotmail.com
01-14-2009, 03:49 PM
Ok this is the deal i have a 2003 hummer h2 i used to like it now its getting on my nerves with the damn sensors i have a tech 2 i bought so it pulled these codes up in the history first one is
1 C0631 RIGHT REAR POSITION SENSOR
2ND IS C0712 LEVEL CONTROL COMPRESSOR RELAY CIRCUIT I LOVE A PART NUMBER FOR THAT SO I CAN BUY IT 3RD THE MOST FAMOUS ANNOYING ONE IS CO711 LEVEL CONTROL AIR PRESSURE SENSOR
AND MY RIGHT IS 3.65 SENSOR VOLTS
LEFT IS 2.53 SENSOR VOLTS THE LEFT ONE GOES UP N DOWN LIKE CRAZY WITH THE SCANNER WHILE DRIVING SO WHAT SHOULD I DO FIRST PLEASE HELP THANK YOU ERIC

HUMTECH
01-14-2009, 08:08 PM
I would start by replacing the relay. It is located below the brake master cylinder on the 03 model year just above the frame rail(dont know the part #). Then try to clear all codes. On level ground with the engine running check your level sensor data again, they should read between 2.5 and 3.5 volts, any lower or higher and they are not in the proper range when sitting still and level. If the right one still is reading high you can try to adjust it but will likely need to be replaced. If you do replace it you will then require a trim height learn procedure.

fbodyguy99@hotmail.com
01-14-2009, 10:04 PM
Ok changed the CO712 relay it was 40 dollars at the dealership i cleared all codes still have the code CO711 i ordered the right rear position sensor today to see if that helps, how do i do the trim height learn procedure? thanks very fast reply i appreciate it tons im from michigan by the way if you have any more advice be great to hear it!:beerchug:

HUMTECH
01-15-2009, 01:39 AM
If you still have the original single stage compressor there is a calibration update for the module for code c0711. ****Do not program a dual stage unit***** it will kill the module. If the calibration update does not correct the problem you will likely require a compressor replacment. The single stage unit is no longer available and you will have to upfit the dual stage unit. Requires a couple of new airlines. The dealer will know which ones you need. Until that code is cleared the trim height learn will not work, it requires that no codes are set current.

HUMTECH
01-15-2009, 01:40 AM
This procedure noted below should be performed after compressor assembly, air suspension control module, or suspension position sensor replacement. Uneven suspension position can also be corrected by performing this procedure.
Tools Required

CH-47816 (http://gsi.xw.gm.com/si/showTif.do?image=1608224) 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.

<LI type=1>Raise the vehicle on a hoist. <LI type=1>Install the CH-47816 (http://gsi.xw.gm.com/si/showTif.do?image=1608224) on to the LR and RR jounce bumper mounting cups. <LI type=1>Lower the vehicle off the hoist. <LI type=1>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 (http://gsi.xw.gm.com/si/cellHandler.do?cellId=68508&refDoc=1618897&from=sm) . <LI type=1>Turn ON the ignition, with the engine OFF. <LI type=1>Install a scan tool. <LI type=1>With the scan tool select Chassis. <LI type=1>Select Air Suspension. <LI type=1>Select Special Functions. <LI type=1>Select Trim Height Calibration and press the Enter key. The scan tool will flash Calibration In Progress, then display Calibration Complete. <LI type=1>Press the Exit key. <LI type=1>Pressurize the air suspension system until the rear weight of the vehicle is lifted of the blocks. Refer to Air Suspension Pressurization (http://gsi.xw.gm.com/si/cellHandler.do?cellId=139592&refDoc=1618897&from=sm) . <LI type=1>Remove the CH-47816 (http://gsi.xw.gm.com/si/showTif.do?image=1608224) . <LI type=1>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.
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.

fbodyguy99@hotmail.com
01-16-2009, 04:23 AM
How hard is it to get rid of the air suspension and go coils and what all do i need to buy for this procedure? and and what all do i have to take out thanks

HUMTECH
01-16-2009, 11:43 PM
Replace the bags with coils and unplug the module at the side of the compressor and remove the relay

fbodyguy99@hotmail.com
01-17-2009, 04:39 AM
so i just have to get coils do i have to buy brackets or anything ?

HUMTECH
01-17-2009, 04:58 AM
Thats a good question. Ill have to look into that one

HUMTECH
01-17-2009, 05:04 AM
Check out this site
http://www.strutmasters.com/catalog.php?cat=146