Circuit/System Description
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 requesting both of the PASSENGER AIR BAG ON/OFF indicators to illuminate for 5 seconds. The SDM will then transmit a request message to the PPS to receive the PPS verification ID. The PPS will transmit the verification ID to the SDM, and the SDM will compare the ID received to data stored in memory. If the data stored in memory does not match the information transmitted by the PPS or the SDM has detects that the PPS has set a current DTC the SDM will then disable the instrument panel (I/P) module deployment loop, set DTC B0081 and illuminate the AIR BAG warning indicator.
The SDM sends a message to the PPS, when commanded by the scan tool to initiate the DTC retrieval process. Both the PASSENGER AIRBAG ON and OFF indicators are illuminated. After the PPS receives this request for data, it will transmit the DTC to the scan tool through the SDM. This data is accessible while the ignition is ON. Do not turn the ignition OFF while displaying PPS DTCs.