Test M: LFC 25/DTC B1871-Passenger Air Bag Deactivation Switch Fault

M1:

M2:

M2 - M4:

M4 - M5:

M6 - M7:

Normal Operation
The Restraints Control Module (RCM) monitors the status of the Passenger Air Bag Deactivation (PAD) switch circuit. The PAD switch signals the RCM by switching a resistance to ground. If the RCM senses 900-1100 ohms in the PAD switch, it enables the passenger air bag and turns off the PAD switch warning lamp. If the RCM senses 400-600 ohms in the PAD switch, it deactivates the passenger air bag and turns the PAD switch warning lamp on. If the RCM detects an invalid resistance, it will store a Diagnostic Trouble Code (DTC) B1871 in memory and flash a Lamp Fault Code (LFC) 25 (or higher priority code if one exists) on the air bag indicator.

Possible Causes
A PAD switch fault could be caused by:
^ a damaged or inoperative PAD switch.
^ a damaged or inoperative RCM module.
^ wiring, terminals, or connectors.