A check control message for the restraint system appears. In the instrument cluster, the red air bag warning light lights up permanently. One of the following fault codes is stored in the ACSM (air bag control unit): 930949 - Knee airbag, driver: short circuit to negative terminal 93094F - Knee airbag, front passenger: short circuit to negative terminal 93094C - Knee airbag driver's side: Resistance too great 930952 - Knee airbag, front passenger: Resistance too great.