GM Service Manual Online
For 1990-2009 cars only

The SIR Scan Tool Data Definitions contains a brief description of all SIR related parameters available on the scan tool. The list is in the order that the list appears on the scan tool.

Ignition: The scan tool displays 0-25.5 volts. The Ignition represents the system voltage which is measured by the SDM at the ignition feed.

Lamp Driver: The scan tool displays Internal or External. The warning lamp control method for a hard wired lamp is Internal. The warning lamp control method for a serial data controlled lamp is External.

Driver Resistance: The scan tool displays 0-6.3  ohms. The SDM performs the resistance measurement test once each ignition cycle and verifies the Ignition Positive Voltage and the 23 VLR voltages are within the normal ranges. Then the SDM sources a constant current to the driver deployment loop. The SDM then measures the voltage drop across the deployment loop and converts the measured voltage value to a driver deployment loop resistance value.

Passenger Resistance: The scan tool displays 0-6.3 ohms. The SDM performs the resistance measurement test once each ignition cycle and verifies the Ignition Positive Voltage and 23 VLR voltages are within the normal ranges. Then the SDM sources a constant current to the passenger deployment loop. The SDM then measures the voltage drop across the deployment loop and converts the measured voltage value to a passenger deployment loop resistance value.

Driver Senselo: The scan tool displays 0-20 volts. The SDM measures the voltage of the driver low terminal voltage and displays the voltage as Driver Senselo

Passenger Senselo: The scan tool displays 0-20 volts. The SDM measures the voltage of the passenger low terminal voltage and displays the voltage as Passenger Senselo.

Driver VDIF: The scan tool displays 0-400 millivolts. The SDM measures the voltage difference between driver high and driver low and displays this voltage difference as Driver VDIF.

Passenger VDIF: The scan tool displays 0-400 millivolts. The SDM measures the voltage difference between passenger high and passenger low and displays this voltage difference as Passenger VDIF.

Warning Lamp Control: The scan tool displays ON or OFF. The warning lamp state commanded by the SDM.

Lamp Driver Feedback: The scan tool displays Active or Inactive. The warning lamp state detected by the SDM.

Warning Lamp ON: The scan tool displays 0-182 hours. The SDM measures the continuous warning lamp on time.

Warning Lamp Cycles: The scan tool displays 0-125 cycles. The ignition cycles of the current warning lamp state.

Driver Seatbelt: The scan tool displays Buckled or Unbuckled. The signal from the drivers seatbelt switch that the seatbelt is fastened.

Pass Air Bag Enable: The scan tool displays High or Low. When the inflatable restraint IP module IP enable/disable switch is in the passenger air bag ON position, the voltage should be high. When the IP switch is in the OFF position the voltage should be low.

Pass Air Bag Disable: The scan tool displays High or Low. When the inflatable restraint IP module IP enable/disable switch is in the passenger air bag ON position the voltage should be low. When the IP switch is in the OFF position the voltage should be high for a moment, then it goes low.

Suppression Lamp Driver: The scan tool displays ON or OFF. Based on the input of the PASS AIR BAG ENABLE circuit the SDM will operate the lamp driver in order to illuminate the passenger air bag off lamp in the IP switch assembly. When the IP switch is in the OFF position, and the ignition switch is turned to the RUN position, the scan tool should indicate OFF for a moment and then ON as the SDM operates the air bag off lamp.