GMC 2004 Envoy Automobile User Manual


 
Electronically Controlled Air
Suspension System
Your vehicle may be equipped with an electronically
controlled air suspension system that automatically
keeps your vehicle level as you load and unload. The
system includes a compressor, two height sensors
and two air springs supporting the rear axle.
The system also has an internal clock to prevent
overheating. If the system overheats, all leveling function
stops until the system cools down. During this time,
the indicator light on the air inflator system will be
flashing.
The ignition has to be on for the system to inflate, in
order to raise the vehicle to the standard ride height
after loading. The system can lower the vehicle to the
standard ride height after unloading with the ignition
on and also for up to 30 minutes after the ignition has
been turned off.
You may hear the compressor operating when you load
your vehicle, and periodically as the system adjusts
the vehicle to the standard ride height.
Load leveling will not function normally with the inflator
hose attached to the inflator outlet. Remove the inflator
hose from the outlet during loading and unloading.
If the vehicle is parked for an extended period of time,
some bleed down of the suspension is normal. Upon
starting the vehicle, proper height will be achieved.
Overload Protection
The air suspension system is equipped with overload
protection. Overload protection is designed to protect
the air suspension system, and it is an indicator
to the driver that the vehicle is overloaded. When the
overload protection mode is on, it will not allow damage
to the air compressor. However, do not overload the
vehicle. See Loading Your Vehicle on page 4-49.
If the suspension remains at a low height, the rear
axle load has exceeded GAWR (Gross Axle Weight
Rating). When the overload protection mode is activated,
the compressor operates for about 30 seconds to one
minute without raising the vehicle depending on the
amount of overload. This will continue each time
the ignition is turned on until the rear axle load is
reduced below GAWR.
4-54