For 1990-2009 cars

### Introduction

When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. When the SDM has completed the power-up mode the SDM will establish communication with the Passenger Presence System (PPS). The PPS will respond by performing diagnostic tests to check for proper circuit continuity and for shorts to ground and voltage within the PPS. If the PPS detects a malfunction, the PPS will set a DTC, then communicate through a non GMLAN communications circuit to the SDM that a malfunction has occurred, while turning the passenger air bag status indicator to OFF. The SDM will respond by disabling the instrument panel (I/P) module deployment loop, setting DTC B0081 and commanding the AIR BAG indicator ON. The SDM notify the driver of a PPS or SIR malfunction by turning ON the AIR BAG indicator on the cluster. The DTCs that the PPS set are non GMLAN and have to be flashed through the PASSENGER AIR BAG ON/OFF indicators located in the center of instrument panel cluster (IPC). The procedures below are designed to assist in the flashing of these codes. Before you start, read these procedures carefully and completely. For further information regarding the PPS refer to SIR System Description and Operation.

### Passenger Presence System (PPS) Flash Code Procedure

Important: When flashing PPS codes, the IPC and dash lights will begin dimming on and off. This is normal operation during the flashing procedure and does not indicate additional system faults.

1. Empty the front outboard passenger seat.
2. Install a scan tool.
3. Turn the ignition ON, with the engine OFF.
4. With a scan tool, request the PPS to flash DTCs.
5. When the PPS receives a valid request to flash DTCs, (current codes are flashed twice, history codes are flashed once) the PPS will perform the following:

5.1. | Illuminate both PASSENGER AIR BAG ON and OFF indicators located on the center of the IPC for 1 second, then turn OFF both PASSENGER AIR BAG ON and OFF indicators for 1 second. It will then start relaying DTCs.

5.2. | The PPS will flash the OFF indicator to indicate the first digit of the DTC (count the number of flashes to obtain the first digit of the DTC).

5.3. | The PPS will flash the ON indicator to indicate the second digit of the DTC (count the number of flashes to obtain the second digit of the DTC).

6. If the flashing procedure was unsuccessful repeat this procedure. Due to the communication status between the SDM and the PPS module, this procedure may have to be repeated until a successful flashing attempt has been achieved.
7. Refer to the Diagnostic Trouble Code (DTC) List - Vehicle to diagnose the DTCs you have obtained.