Circuit Description
The Passlock™ 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 security system sensor power and low reference for the Passlock™ sensor. The BCM also measures the security system sensor voltage.
When the correct key is used to start the vehicle, a magnet on the lock cylinder passes close to the Passlock™ sensor within the ignition lock cylinder case. The magnet activates the security hall effect sensor in the Passlock™ 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 the valid range, the BCM will send a class 2 message to the powertrain control module (PCM) to enable vehicle starting. If the voltage measured is not within the valid range, a class 2 message will be sent to the PCM to disable starting of the vehicle.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B3033 Security System Indicates Tamper
Conditions for Setting the DTC
| • | The analog voltage signal sampled at the BCM Passlock detection circuit is a tamper signal indicating a Passlock tamper. |
| • | This condition must be present during an engine start attempt. |
Action Taken When the DTC Sets
When attempting to start the engine and the Passlock sensor sends a tamper signal, the BCM will take one of 2 actions:
| • | If the BCM programming mode is not active AND the BCM is not in fail enable mode, then: |
| - | The BCM stores DTC B3033 in memory. |
| - | The BCM sends a message to the instrument cluster to flash the SECURITY indicator. |
| - | The BCM sends a message to the PCM via the class 2 serial data link to disable the crank relay and fuel delivery to the engine. |
| - | The BCM disables sampling of the Passlock sensor analog voltage signal for a time-out period of 10 minutes. |
| - | If the ignition switch is left on for at least 10 minutes, the BCM enters the theft deterrent re-learn mode. |
| • | If the BCM programming mode is active AND the BCM is in fail enable mode, then: |
| - | The BCM stores DTC B3033 in memory. |
| - | The BCM sends a message to the instrument cluster to turn on the SECURITY indicator. |
| - | The BCM will send a message to the PCM via the class 2 serial data link to enable the crank relay and fuel delivery to the engine allowing the engine to start. |
Conditions for Clearing the DTC
| • | A current DTC B3033 clears when the BCM detects a valid Passlock sensor code. |
| • | When the BCM detects a valid code from the Passlock sensor, the ignition switch must be cycled from OFF to ON before this DTC can change from a current DTC to a history DTC. |
| • | A history DTC clears after 100 consecutive ignition cycles if the condition for the malfunction is no longer present. |
Diagnostic Aids
| • | A malfunctioning Passlock sensor may cause an intermittent malfunction to occur. |
| • | If the SECURITY indicator is flashing, the BCM Passlock has entered a vehicle disable state that will last approximately 10 minutes. Disconnecting the battery will not clear the timer sequence, it will resume when battery power is restored. Even if a proper Passlock sensor code is read during the vehicle disable period, the vehicle will not start until the 10 minute time period has elapsed. After this 10 minute time period, the SECURITY indicator will change from a flashing state to a solid ON state. At this time, the BCM enters the theft deterrent re-learn mode. The engine will start if the BCM detects the correct Passlock sensor code. |
| • | Check for poor connections at both the BCM and the ignition lock cylinder assembly which could cause an open, incorrect Passlock sensor voltage signal, or intermittent malfunction. |
| • | DTC B2958 may set in the BCM when the ignition switch is on with the Passlock sensor electrical connector disconnected. When BCM diagnostics and repairs are completed for DTC B3033, clear the BCM DTCs. |
Test Description
The number below refers to the step number on the diagnostic table:
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Theft Deterrent System Schematics Connector End View Reference: Theft Deterrent System Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the scan tool display DTC B3033 as a current DTC? | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems |
Inspect the area around the ignition lock cylinder for any device which could create a magnetic field (audio speaker, magnet, etc.). Is there a magnetic device near the ignition lock cylinder? | Go to Step 4 | Go to Step 5 | |
4 | Remove the device creating the magnetic force. Did you complete the repair? | Go to Step 8 | -- |
5 | Inspect for poor connections at the Passlock sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 8 | Go to Step 6 |
6 | Replace the Passlock sensor. Refer to Ignition and Start Switch Replacement in Instrument Panel, Gages, and Console. Did you complete the replacement? | Go to Step 7 | -- |
7 | Perform the Passlock learn procedure. Refer to Programming Theft Deterrent System Components . Did you complete the repair? | Go to Step 8 | -- |
8 | You may have to wait up to 10 minutes in order to reset the BCM and synchronize all of the Passlock components.
Does the DTC reset? | Go to Step 3 | System OK |
