B2957

DTC B2957

CIRCUIT DESCRIPTION
The Passlock System is provided in order to prevent vehicle theft if the ignition lock cylinder is forced to rotate. The Passlock controller reads the coded Passlock data signal. The data consists of a voltage generated by a voltage divider network created between the Passlock assembly and the Passlock controller. If the data is correct, indicating rotation of the lock cylinder with the proper mechanically cut key, the Passlock controller sends a password to the powertrain controller via serial data to indicate that engine starting should be allowed. The Passlock controller also interfaces with the driver displays subsystem to indicate, via the security indicator, the Passlock subsystem status and acute subsystem failures.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC B2957 Security System Sensor Data Circuit Low

CONDITIONS FOR SETTING THE DTC
- The ignition switch is ON.
- The body control module (BCM) signal input is less than 0.4 volts for 1 second.

ACTION TAKEN WHEN THE DTC SETS
- The vehicle will not start if the fault occurs before you start the vehicle. The security indicator will be ON steady.
- If the vehicle is running when the fault occurs, the BCM will be in the fail enable mode allowing the vehicle to start and run. The security indicator will be ON.

CONDITIONS FOR CLEARING THE DTC
- The DTC will clear once the ignition cycle has occurred without the fault recurring.
- The BCM history codes will clear once 100 concurrent ignition cycles occur without the fault recurring.
- Using a scan tool.

DIAGNOSTIC AIDS
- Inspect the Passlock sensor harness for an intermittent or a short to ground.
- Following a repair, the tamper timer may need 10 minutes in order to expire.

TEST DESCRIPTION

Step 1 - Step 10:

Step 11:

The numbers below refer to the step numbers on the diagnostic table.
2. This step tests for proper operation of the 5-volt reference from the BCM.
3. This step tests for the Passlock return circuit.