Component Tests and General Diagnostics

The Body Control Module (BCM) generates audible warnings for seven conditions: headlamps reminder, ignition key reminder, seat belt reminder, turn signal reminder, park brake reminder, auxiliary audible reminder, and a check gages alarm. The headlamps reminder, park brake reminder, turn signal reminder, auxiliary audible reminder, and the check gages alarm are pulsed approximately once every one half second, sounding the quickest. The ignition key reminder is pulsed once every second. The seat belt reminder is a continuous tone.

Headlamps Reminder
When the headlamp switch is in the PARK or HEAD position, voltage is removed to the lamps off input of the BCM. When the ignition switch is turned out of the RUN position, voltage is removed from the ignition switch input of the body control module. When voltage is removed at the lamps off input and no voltage applied to the ignition switch input, the body control module will sound the headlamps warning.

Ignition Key Reminder
The BCM applies voltage at all times to the ignition switch. When the ignition key is placed into the ignition switch, the ignition switch is closed. When the LH front door is open, the LH front door ajar switch closes the circuit to ground. The BCM senses a voltage drop at the ignition key input and will sound the ignition warning.

Seat Belt Reminder
The BCM applies voltage to the seat belt switch at all times. The BCM senses a voltage drop at the seat belt input through the closed contacts of the seat belt switch when the driver's seat belt is unlatched. When the driver's seat belt is latched, the seat belt switch is opened and the body control module senses voltage at the seat belt input. When the ignition switch is turned to RUN, voltage is applied to the BCM ignition switch input. When voltage is present at the ignition switch input and 0 volts at the seat belt input, the BCM will sound the seat belt warning for 4 to 8 seconds. If voltage is present at the ignition switch input and the seat belt input, the body control module will disable the seat belt warning.

Turn Signal Reminder
When a turn signal is operated, a signal is sent along the class II serial data line from the instrument cluster to the BCM. The BCM begins to monitor vehicle distance through the class II serial data line. If the turn signal is still flashing after the vehicle has traveled 1.20 kilometers (0.75 miles), the turn signal warning chime will sound, and continue to sound, until the input conditions are no longer met or until a warning condition of higher precedence is detected.

Park Brake Reminder
The BCM will provide a park brake reminder intended to alert the driver in case of the park brake being set and the gear selector is removed from the PARK or NEUTRAL position. The park brake reminder will be activated when the park brake switch is applied, there is an ignition input at connector C1 terminal C12, and the gear selector is not in the PARK or NEUTRAL position, as indicated via the class II serial data line. When the above conditions are met, the BCM shall sound an audible warning and continue to sound this warning until the input conditions are no longer met or until a warning condition of higher precedence is detected.

Check Gages Alarm
The BCM will provide a check gages alarm intended to alert the driver to check the instrument cluster gages. This function is accomplished through the use of the class II serial data line. Upon receiving the chime command through the class II serial data line, the BCM shall sound an audible warning and continue to sound this warning until the input conditions are no longer met or until a warning condition of higher precedence is detected.

Auxiliary Audible Reminder
The BCM will provide a auxiliary audible reminder intended to provide a method for a non-class II external subsystem to activate a sound alarm. The auxiliary chime input shall be monitored when there is an ignition input at connector C1 terminal C12. An auxiliary ground switch can be connected to connector C1 terminal C10 for an external subsystem. When this switch is grounded and an ignition 1 input is applied, the BCM shall sound an audible warning and continue to sound this warning until the input conditions are no longer met, or until a warning condition of higher precedence is detected.

Body Control Module (BCM) Diagnostic Trouble Codes (DTCs)
The BCM may set DTCs for the following functions or the BCM relating to audible warnings:
^ B0608 - BCM Power Malfunction
^ B2417 - Daytime Running Lamps (DRL) Control Module Circuit (Shorted to Ground or Open)
^ B2418 - DRL Control Module Circuit (Shorted to Voltage)
^ B2739 - Key In Ignition Fault
^ U1096 - I/P Class II Source ID 60
^ U1255 - Loss of Class II Serial Data Fault (General)
^ U1300 - Class II Data Link Shorted to Ground
^ U1301 - Class II Data Link Shorted to Voltage
Refer to Body Control Module for DTCs and diagnostic procedures regarding these codes. Testing and Inspection