The Passlock immobilizer system is provided in order to prevent vehicle theft if the ignition lock cylinder is forced to rotate or the ignition switch is operated while separated from the ignition lock cylinder case. The body control module (BCM) provides a 12 volt reference and low reference for the Passlock sensor. The BCM also measures the security system sensor voltage via the signal circuit.

When the ignition cylinder is rotated with a proper mechanically cut key, a magnet on the cylinder passes near the Passlock sensor within the ignition lock cylinder case. The magnet activates the security hall effect sensor which completes a circuit from the security sensor signal circuit through a resistor to the security sensor low reference circuit. The resistance value will vary from vehicle to vehicle. The BCM will measure the voltage on the security sensor signal circuit and compare this voltage to a previously learned voltage. If the voltage measured is within a valid range, the BCM will send a fuel enable serial data message to the engine control module/powertrain control module (ECM/PCM) to enable vehicle starting. If the voltage measured is not within the valid range, a fuel disable serial data message will be sent to the ECM/PCM to disable starting of the vehicle.

Ignition is in the ACCY or RUN position

B2945

Voltage seen by the TDM at the security system sensor supply voltage circuit is greater or less than the expected value.

B2955

Voltage seen by the TDM at the security system sensor signal circuit is not within the specified range.

B2960

Voltage seen by the TDM at the security system sensor signal circuit is within the specified range, but not the learned value.

B3033

The TDM has determined a tamper condition exists within the Passlock sensor.

Schematic Reference

Immobilizer Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Immobilizer Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Inspect the area around the ignition lock cylinder and verify there are no items which may create a magnetic field such as an audio speaker or a magnet near the Passlock sensor.

⇒	If any items are near the Passlock sensor which may create a magnetic field, remove them.

2. Momentarily rotate the ignition switch to CRANK, but do not start the vehicle, while observing the scan tool Passlock Data Voltage parameter. The parameter should be between 0.4 and 4.9 volts.

1. Ignition OFF, disconnect the harness connector at the Passlock sensor.
2. Ignition OFF, test for less than 10 ohms between the low reference circuit terminal 2 and ground.

⇒	If greater than the specified range test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the BCM.

3. Ignition OFF, test for less than 1 volt between the 12-volt reference circuit terminal 3 and ground.

⇒	If greater than the specified range, test the 12-volt reference circuit for a short to voltage. If the circuit tests normal, replace the BCM.

4. Ignition ON, test for 11.8-12.2 volts between the 12-volt reference circuit terminal 3 and ground.

⇒	If not within the specified range, test the 12-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

5. Verify the scan tool Passlock Data Voltage parameter is greater than 4.9 volts.

⇒	If less than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the BCM.

6. Install a 3A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool Passlock Data Voltage parameter is less than 0.4 volts.

⇒	If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance.

7. Ignition OFF, connect the harness connector at the Passlock sensor.
8. Ignition ON, verify the scan tool Passlock Data Voltage parameter remains steady (+/- .02 volts) between 0.4 and 4.9 volts for one minute.

⇒	If not within the specified range or the value does not remain steady, replace the Passlock sensor.

9. Perform the 10 Minute Immobilizer Relearn procedure. Refer to Immobilizer System Component Programming . The BCM should learn the Passlock data voltage and the vehicle should start.

⇒	If the BCM does not learn the data voltage or the vehicle does not start, replace the BCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.