For 1990-2009 cars

### Circuit Description

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.

In case of the belt pretensioner explosion without front air bag inflation due to insufficient impact, replace the exploded belt pretensioner and remove the defect code using the scan tool. If the belt pretensioner explosion counts over 5, the SDM should also be replaced.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1657 Deployment Commanded Pretensioner

### Conditions for Running the DTC

Ignition voltage is within the normal operating voltage range.

### Conditions for Setting the DTC

The history of the belt pretensioner explosion is in the SDM.

### Action Taken When the DTC Sets

The SDM commands the AIR BAG indicator ON.

### Conditions for Clearing the DTC

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