Rear Air Ride Random Drops / Air Blending Door

[HUMTECH]

#PIT3509: 2003-2005 Hummer H2 Vehicle Sits Low or the Suspension Sags Overnight - keywords AIR control DTC ECAS ELC electronic height inoperative leak MIL module rear spring trim - (Mar 23, 2005)

Subject:2003-2005 H2 Hummer Vehicle Sits Low or the Suspension Sags Overnight

Models:

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1634083&from=sm#ss1-1634083">Condition/Concern:

Some customers may comment that the rear of the vehicle sits low and/or the suspension sags overnight.
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1634083&from=sm#ss2-1634083">Recommendation/Instructions:

Check the following locations for a leak using a soap and water solution in a spray bottle.

1. <LI type=1>Left and Right Inlet Valves. <LI type=1>Exhaust Valve. <LI type=1>Suspension Air Supply Lines that run from the Inlet Valves to the Right and Left Air Springs (Airbags).
2. Air Spring fittings and the Air Spring itself.

Leakage can produce big bubbles or just some beer like foam appearance. If the leak is isolated to the valve block assembly, do not replace the entire compressor assembly. The valve block can be obtained separately by ordering part number 88982408 for the single stage compressor or part number 89060584 for the dual stage compressor.
Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1634083&from=sm#ss3-1634083">Models:

(2003-2005 Hummer H2)

[HUMTECH]

#PIT3472: 2003-2005 H2 Hummer Rear Suspension Sags/Leak Down Specification - keywords AIR DTC ECAS ELC electronic height inoperative MIL Module trim - (Mar 4, 2005)

Subject:2003-2005 H2 Hummer Rear Suspension Sags/Leak Down Specification

Models:

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1618502&from=sm#ss1-1618502">Condition/Concern:

Some customers may comment that the rear end of the vehicle appears to sag after the vehicle sits overnight or longer. After the vehicle is started, the rear of the vehicle rises to normal operating level.
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1618502&from=sm#ss2-1618502">Recommendation/Instructions:

To correctly measure for a concern, use the rear suspension "D" height measurement. The D height is obtained by measuring the distance between the edge of the jounce cup along the jounce bumper center line and the jounce pad on the rear axle (See SI Document ID # 796914).
A 1.0 mm (0.040 in) leak down drop of the rear end over a 24 hour period is considered normal.
Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1618502&from=sm#ss3-1618502">Models:

(2003 - 2005 H2 Hummer)

[myrddin]

Wow... good info... Should I be measuring the bumpstop travel instead of the ground to fender?

I was not able to see any bubbles, but to be honest I had a hard time getting to the top of the compressor... He (the tech I talked to) said I would never find that valve, I guess it’s not made any more? But let me ask you this... if I do what he said and the condom (or whatever balloon I can find to fit) fills with air... should I replace the valve if I can get it to still reprogram first.

For the heck of it I am going to soap it all down agn tomorrow after work I will do a better job at trying to soap up the fittings on the compressor.... If I see no bubbles I will put the balloon on the exhaust line at the filler neck and see if it airs up... if it does I need to figure out what to do...

1. Replace the compressor valve
2. Have dealer reprogram
3. Replace the single compressor with dual (I don’t have the money but I can start to save up or find one used)

You guys are real cool for lending a hand...

I value your opinion please help me get my mind straight and I will try to get it right.


do you think my steps sound right?

[HUMTECH]

I would try the program. The valve is not a service part but part of the complete assembly. So if the 100 dollar program works, great. If not your gonna have to replace the compressor at a huge cost. In my opinion a good 100 bucks to spend on diagnosis before the 2500 dollar plus repair.

[HUMTECH]

But like the tech you were talking too it may be a good idea to start thinking about the upgrade for sure.

[myrddin]

Thursday Morning:7:25am
-driver 41 1/4 (minus 1 mm)
-Pass 40 1/2

Parked at work 8:15am
-driver 41 3/4 (minus 1 mm)
-Pass 40 3/4 (minus 1 mm)

So its my guess that from your posting that this is normal (no real drop over the past 24 hours)...

Thinking back I am wondering if I only notice the big drop after I put it into off road mode and then back to normal... if I have not seen a drop by end of day I will test that tonight. If that is the case programming would start to add up for me... But I do not think that is it.

HUMTECH you are real cool to take the time to lend us clueless guys a hand... Let me ask... other than testing out my theory above on the off-road mode triggering the rear drop... Do you still think I should just take it over for a scan? or should I test the exhaust valve for failure first... and I found 2 guys that have the dual stage compressor (one with hoses and bags) that I can get "Used" for under 400.00... should I skip the scan and just do that? I mean I would hate to pay 400 or so when I may get away with 100.00. But also I would hate to spend 100 on something that will not help when i can add that to the total for the parts I need... those compressors will not last long at that price I wouldn't think...

thanks

[HUMTECH]

If you can get a working dual stage setup that cheap i would grab it. Once installed it will have to go to the dealer though to have the trim height learned