Bravada 2WD L6-4.2L VIN S (2002)
Air Line: All Technical Service Bulletins
Rear End - Sags After Sitting Overnight
File In Section: 03 - Suspension
Bulletin No.: 01-03-99-001
Date: August, 2001
TECHNICAL
Subject:
Rear End of Vehicle Sags After Vehicle Sits Overnight
(Repair Air Leak In Electronically Controlled Air Suspension (ECAS)
Models:
2002 GMC Envoy
2002 Oldsmobile Bravada
with Electronically Controlled Air Suspension (RPO G67)
Condition
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 end rises to normal operating level.
A 1.5 mm (0.060 in) leak down drop of the rear end over a 24 hour period is considered normal.
Cause
An air leak in the ECAS system may cause the rear suspension air springs to lose pressure.
Correction
Follow the service procedure below in order to diagnose the cause of the air leak.
Air Leak Diagnosis
Important:
Remove the # 1 30 amp ECAS fuse from the UBEC before starting the vehicle.
1.
Drive or push the vehicle into the service bay and raise the vehicle off of the ground. Refer to the Lifting and Jacking the Vehicle information in
the Service Manual.
2.
Inspect the rear air springs and document on the repair order which one of the springs is collapsed. The collapsed air spring generally is the circuit
that is at fault and is not holding pressure.
Caution:
A sudden release of pressure may cause personal injury or damage to the vehicle. The air suspension system is under pressure until the air supply
lines are disconnected. Use the following precautions when servicing the air suspension system:
^
Wear gloves, ear protection, and eye protection.
^
Wrap a clean cloth around the air supply lines.
3.
Inspect the air lines at the ECAS compressor ferrule nuts for proper installation. Each air line has a bubble 18-22 mm (0.70-0.80 in) from the end
of the line that acts like a stop. The bubble should be seated next to the ferrule nut with the line fully seated. If the air line is not fully seated,
loosen the ferrule nut and push the line in until the line stops or the bubble is within 2 mm (0.08 in) from the ferrule nut.
Important:
Do not over tighten the ferrule nut.
4.
Inspect the ferrule nut for the proper torque.
Tighten
Tighten the ferrule nuts to 2.5 N.m (22 lb in).
