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

Pinpoint Test M1:

Pinpoint Test M2:

Pinpoint Test M3-M4:

Pinpoint Test M5:

Pinpoint Test M6-M8:

Pinpoint Test M: LFC 25/DTC B1871 - Passenger Air Bag Deactivation (PAD) Switch Fault

Normal Operation

The air bag Electronic Crash Sensor (ECS) module monitors the status of the Passenger Air Bag Deactivation (PAD) switch at ECS module C223-9, circuit 1112 (WH/LB). The PAD switch signals the ECS by switching a resistance to ground. If the ECS senses 900-1,100 ohms in the PAD switch, it enables the passenger air bag and turns off the PAD switch warning lamp. If the ECS senses 400-600 ohms in the PAD switch, it deactivates the passenger air bag and turns the PAD switch warning lamp on. If the ECS 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 passenger air bag deactivation switch fault can be caused by:
- a damaged or inoperative PAD switch.
- a damaged or inoperative ECS module.
- a short to battery, short to ground or open on circuit 1112 (WH/LB).