For 1990-2009 cars

### Description

When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) will establish communication with the passenger presence system (PPS). When communication is established, the SDM will first request traceability/verification information from the PPS. If the SDM confirms that the correct PPS is in the vehicle, then the SDM will request the PPS status Data. If the PPS detects a malfunction, the PPS will set a DTC, and communicate with the SDM that a malfunction has occurred. The SDM will respond by disabling the instrument panel (I/P) module deployment loop, and then sets DTC B0081 while commanding the AIR BAG indicator ON to notify the driver of a PPS malfunction. The DTCs that the PPS set are non GMLAN and have to be retrieved through the SDM. The procedures below are designed to assist in the retrieval 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 .

### PPS Displaying Code Procedure

Important: When the sensing and diagnostic module (SDM) starts to communicate with the PPS, the instrument panel cluster (IPC) and dash lights will begin dimming on and off. This is normal operation during this procedure and does not indicate additional system faults.

1. Empty the front outboard passenger seat.
2. Install a scan tool.
3. Turn ON the ignition, with the engine OFF, and wait for the PPS to complete its bulb check function.
4. With the scan tool, request the passenger presence system (PPS) DTCs. The scan tool will command the SDM to send a message to the PPS, which will initiate the DTC retrieval process. (This process will take about 13 seconds).
5. When the PPS receives a request for DTCs, the PPS will illuminate both PASSENGER AIR BAG ON and OFF indicators located on the IPC for 3 seconds. If the PPS does not turn ON both indicators within 20 seconds of the request for PPS DTCs, then repeat step 4.
6. After the passenger AIR BAG ON and OFF indicators have illuminated for 3 seconds, cycle the ignition OFF for 3 seconds then turn the ignition back ON.
7. After the PPS receives this request for data from the SDM, it will transmit the DTC data through the SDM to the scan tool. This data is only accessible for one ignition cycle, do not turn OFF the ignition while displaying PPS DTCs.
8. The scan tool will then show any current or history DTCs. Refer to the Diagnostic Trouble Code (DTC) List - Vehicle to diagnose the DTC you have obtained.