B0004 MERCURY - Driver Knee Bolster Deployment Control
Faulty Driver Knee Airbag
Driver Knee Airbag harness is open or shorted
Driver Knee Airbag circuit poor electrical connection
When is the code detected?
If the Restraints Control Module (RCM) detects a short between the driver knee air bag circuits and the circuits of another SRS component, it sets this Diagnostic Trouble Code (DTC) and the DTC of the corresponding SRS component.
Air Bag Warning Light ON
B0004 Mercury Description
The Restraints Control Module (RCM) monitors all deployable device and sensor circuits for a signal cross coupled (short) between circuits. If the RCM detects a short between the circuits of one device and another device, it will store a DTC for each of the signal cross coupled faults in memory. The RCM sends a message to the Instrument Panel Cluster (IPC) to illuminate the air bag warning indicator. When a normal loop fault is present (one loop is either shorted to battery/ground, open circuit or low resistance), then signal cross coupled diagnostics will not be active. Once the normal loop fault is repaired, then the signal cross coupled diagnostics will resume.