TPMS System Module
WARNING: This page is about a different car, the 2007 Lincoln Mark LT and 2007 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.
The VSM contains the TPMS functionality. Refer to Tire Pressure Monitoring System in Diagnosis and Testing for TPMS fault diagnosis and repair.
The VSM compares the information of each tire pressure sensor transmission against a pressure limit. If the VSM determines that the tire pressure has fallen below the low limit, the VSM communicates this to the instrument cluster on the vehicle communication bus.