Just Read A Thread on" Check Engine Light Air Suspension" I have a "TQ"

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May 26, 2026 | 10:33 AM

#11

Mark R

Thread Starter

Senior Member

Joined: Feb 2010

Posts: 1,093

From: Egg Harbor Township NJ

Quote:

Originally Posted by Brunob00

@Mark R - Let me know if you were able to do the following... if not, I have a Tech2 and an H2 with air suspension and I will perform this test on mine tomorrow and confirm the procedure.

1. Connect the Tech 2

Connect the GM Tech 2 to the DLC/OBD-II port under the dash.
Turn ignition to RUN (engine can be off initially).
It’s better to have a battery charger connected because the compressor can draw significant current during testing.

2. Navigate to the Suspension Module

On the Tech 2 menu:

Code:

Diagnostics
→ Model Year: 2008
→ Light Duty Truck
→ Hummer
→ H2
→ Chassis
→ Air Suspension / Suspension Control Module

Depending on Tech2 software version, it may say:

“Electronic Suspension Control”
“Air Suspension Control Module”
“ECAS”

What to Check

A. Read Diagnostic Trouble Codes (DTCs)

Go to:

Code:

DTC Information
→ Current DTCs
→ History DTCs

Common H2 air suspension codes include:

C0563
C0626
C0660
C0696
C0702
C0711

Thanks Bruno,
I have a Tech 2.
So this morning 5/26/26 I looked out the window as I do every morning to check ride height. I noticed it was down about half way. I haven't driven the 2 since Saturday. so it has been sitting since the 23rd. That tells me there is in fact a Leak in the bags or the air lines. I fired it up and the 2 came up to level and the compressor shut off.

Then I hit the raise button and it jacked up 2 more inches. Then hit it again and it went back to ride hight. I could hear the valve close on the compressor. So at this point I was wrong...meaning that it now sounds like the compressor is OK and in fact there is a very slow leak in the lines or bags.

So what to do now? Get bags and lines replaced? Then I'd be dealing with a 17 year old compressor with no availability and or parts and a new set of bags and or air lines? Does that make sense? Or just put the new springs and shocks in and trash the Air Ride system and Sell the compressor as it's still working and recoup the money for the springs and shocks and make a Profit?

Problem is it's not a toy and is my daily driver which means ...driving 75 miles to the shop...renting a car for XX dollars a week and having the bags done or the springs done. With a 17 year old compressor would you take a shot at this repair?

If there was a Complete Compressor Available to buy, I would by one as a spare and get the bags and lines replaced and keep the old compressor in service. So that's the conundrum.

I tend to be leaning towards springs and selling the compressor. And your thoughts are?

Today | 09:44 AM

#12

Brunob00

Senior Member

Joined: Jun 2021

Posts: 253

From: Pittsburgh

Got it... ok, so I think you are right... if it is a daily driver, fixing the existing air compressor is probably a no-go. It would probably take several weeks and many transport dollars as both Predator and Mash Motors require you to send the H2 in to repair that compressor.