Diagnostic Energy Reserve Module (DERM)

CAUTION: When performing service on or around SIR components or SIR wiring, follow the procedures listed below to temporarily disable the SIR system. Failure to follow procedures could result in possible air bag deployment, personal injury or unneeded SIR system repairs.

The DERM in 1993 and previous Driver-Only SIR systems can maintain sufficient voltage to cause a deployment for up to 10 minutes after the Ignition switch Is turned "OFF", the battery is disconnected or the fuse powering the DERM is removed.

The DERM in 1994 and later Driver-Only and the DERM in all Driver-Passenger SIR Systems can maintain sufficient voltage to cause a deployment for up to two minutes after the ignition switch is turned "OFF", the battery is disconnected or the fuse powering the DERM is removed.

Many of the service procedures require removal of the AIR BAG fuse and the disconnection of the inflator module from the deployment loop to avoid accidental deployment. If the inflator module is disconnected from the deployment loop as noted in the "Disabling the SIR System" procedure, service can begin immediately without waiting for the 10 minute or 2 minute time period to expire.