When the ignition switch is turned to ON, the sensing and diagnostic module (SDM) will perform a turn-on test to diagnose critical malfunctions within the SDM itself.

This diagnostic procedure supports the following DTC:

DTC B1620 ECU Performance

Ignition voltage is within the normal operating voltage range.

The SDM does not implement diagnostic operation. In case of the above, the wiring harness of the SDM should be inspected before replacing the SDM.

The SDM commands the AIR BAG indicator ON.

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.