Normal Operation

The safety belt buckles are comprised of integrated circuits called a Hall-effect switch. The safety belt buckle switches indicate to the Restraints Control Module (RCM) whether the safety belt buckles are buckled or unbuckled.

The RCM  supplies current to the safety belt buckle switch. Current flows through the switch, buckled or unbuckled to ground. The RCM  will sense the difference in this current draw, 3 mA (unbuckled) or 8 mA (buckled), and use this information in determining the deployment rate of the dual-stage driver and passenger air bag modules.

The RCM  supplies current to the safety belt buckle switch. Current flows through the switch, buckled or unbuckled to ground. The RCM  will sense the difference in this current draw, 3 mA (unbuckled) or 8 mA (buckled), and use this information in determining the deployment rate of the dual-stage driver and passenger air bag modules.

The RCM  checks the passenger safety belt buckle switch circuits for faults. If the RCM  detects resistance (current) out of range fault, it will store DTC B2439 in memory and flash Lamp Fault Code (LFC) 52 on the air bag warning indicator. After the LFCs  are displayed, the air bag warning indicator will remain illuminated for the rest of the ignition cycle.

• DTC B2439 (Passengers Seat Belt Buckle Switch Resistance Out of Range) - If the RCM  detects a current out of range between buckled and unbuckled on the passenger safety belt buckle switch, it will set this DTC.

  This pinpoint test is intended to diagnose the following: 

• Wiring, terminals or connectors
• Passenger safety belt buckle assembly
• RCM