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. If the RCM  detects resistance (current) out of this range, it will set a DTC.

If the RCM  detects an open circuit or short to voltage fault, it will store DTC B2691 in memory and send a message to the Instrument Cluster (IC) module to flash a Lamp Fault Code (LFC) 51 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 B2691 (Seat Belt Buckle Switch Circuit Fault, Front Driver's Side) - If the RCM  detects an open or short to battery on the driver safety belt buckle switch circuit for greater than 2.5 seconds, it will set this DTC.

  This pinpoint test is intended to diagnose the following: 

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