Pneumatic safety system — general information (Chevrolet Tahoe 1)

Contents: Description ↧ Sensors ↧ Diagnostic modules DERM or SDM ↧ Carrying out work near the pneumatic… ↧ Disabling the pneumatic safety system ↧ Turning on the system ↧

Description

1. The vehicles in question are equipped with a pneumatic safety system (SIR system), which is designed to protect the driver and passenger from injury in the event of a frontal collision.

2. The system includes an airbag, which is located in the center of the steering wheel (on some later models the airbag is also located in the dashboard on the passenger side), three crash sensors mounted at the front of the vehicle and underneath the vehicle, and a diagnostic DERM module mounted under the dashboard (on 1995 and 1996 models.), or SDM module installed under the driver's seat (on 1997 and 1998 models.).

Sensors

3. Two crash sensors are mounted at the front of the vehicle on the frame and one sensor that activates the system is located on the left side of the vehicle (see photo).

4. Front inertial sensors. The system readiness sensor is calibrated to provide voltage to the airbag module when the vehicle speed drops sharply, accelerating the deployment of the module. An electrical signal from the crash sensors is sent to the DERM module, which shorts the airbag module circuit to ground and triggers the airbag.

Diagnostic modules DERM or SDM

5. The diagnostic module contains a built-in microprocessor that controls the operation of the system. When a malfunction is detected in the system, the AIRBAG display starts to light up (on a working system this display goes out after flashing seven times). In this case, the car should be immediately taken to a car service center. Maintenance of the system and troubleshooting is performed only in a car service center.

Carrying out work near the pneumatic safety system

8. When working near the steering column, receiver, instrument panel, etc., please note that the pneumatic safety system wires are placed in a bright yellow tube. Do not touch devices that are connected by wires in a bright yellow tube. Disconnect the pneumatic safety system beforehand.

Disabling the pneumatic safety system

9. Set the steering wheel to the straight ahead position. Turn the ignition key to the Lock position and remove the key from the lock. Remove the fuse from the relay and fuse box (see photo).

10. Remove the knee pad and the noise pad under the instrument panel. To disable the driver's side airbag, disconnect the yellow connector (CPA connector) at the base of the steering column (see photo). To disable the passenger side airbag, disconnect the yellow connector attached to the bracket to the right of the steering column.