Circuit Description

WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.

Front end discriminating sensor uses a unidirectional 2-wire circuit. Front end discriminating sensor modulates current on the interface to send identification, State Of Health (SOH) and deployment commands to Sensing and Diagnostic Module (SDM). SDM serves as a power source and ground for front end discriminating sensor. When ignition is turned on and front end discriminating sensor detects power from SDM, front end discriminating sensor responds by performing internal diagnostics and sending identification to SDM. SDM considers identification message to be valid if received within 5 seconds of front end discriminating sensor powering up. Front end discriminating sensor continually communicates a status message to SDM. When fault is detected, SDM will attempt to reset front end discriminating sensor twice by removing and applying power. If fault is still present, DTC will set.