Circuit/System Description
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
The inflatable restraint sensing and diagnostic module (SDM) stores a 4-digit primary key for the inflatable restraint vehicle rollover sensor (ROS). The SDM sends the ROS the primary key. If the ROS determines that it is the wrong primary key, the ROS will set DTC B1001 and send the SDM a vehicle mismatch message. The SDM then will set DTC B0090 3A and turn the SIR warning indicator ON. The ROS does not use a secondary key.