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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), GMC Mechanic
Category: GM
Satisfied Customers: 29582
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Envoy: electronically controlled air suspension system

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having trouble with the electronically controlled air suspension system on our 2004 GN\MC Envoy. Sometimes does not automatically raise on start up. Have to remove the fuse & then put fuse back to activate system. Any thoughts on solutions ?

Greetings and Welcome to Just answer.

OK, the first thing I want to try is after you start it again, sit on the back of your vehicle to lower it and see if it responds to the change in height. If not then you will need to get the code from the system.

Diagnostic Trouble Code (DTC) Displaying

The Air Suspension system has an internal clock to prevent overheating if the compressor assembly is running for a prolonged period of time. If the system overheats, all leveling function stops until the system cools down. During this time, the indicator LED on the air inflator switch will be quickly flashing at a constant rate.

The other three diagnostic trouble codes are displayed with a blink code on the inflator switch LED. The Air Suspension Compressor Assembly shall begin to indicate the code when the condition to cause the code becomes current.

The number of the fault code shall be represented by the number of flashing pulses on the inflator switch LED. The flashing pulses shall have a repetition rate of 0.5 seconds and each code shall be separated by a 3.0 second delay. All codes shall be flashed in the order of occurrence of the fault. The blink code shall take priority over other processes that have access to the inflator switch LED.

Let me know the code and I will assist you further.



Customer: replied 7 years ago.
where is the air inflator switch & led located ?

THat is in the rear trim inside behind an access panel most likely right.


Customer: replied 7 years ago.
ok started up put weight in back system kicked on. no light on led . turn off turned on compressor & light was steady no blinking. The problem usually occurs over night or when car has been sitting for a while. upon start up the system does not start & thus does not raise up

OK, I think the issue is with the level sensor on the reat suspension.

Object Number: 731567  Size: SH

Customer: replied 7 years ago.
How do you test it ? Are these able to be rebuilt or do you just replace it ? Approx. how much does one cost & installation cost ?
There are actually 2, one on each side. Each sensor is about 200 and installation should be about 1/2 hour each. I Would try to get codes using the procedure I posted before anything else.
Customer: replied 7 years ago.
ok. so i should wait until this occurs & check the led for the flashing code. If there is no code flashing, what is the next step.
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