Circuit Description
The Passlock theft deterrent system contains a Passlock sensor that is part of the ignition lock cylinder assembly. The body control module (BCM) provides voltage (B+) to the Passlock sensor through the Passlock sensor power circuit when the ignition switch is in the ACCESSORY, ON, or START position. The BCM also provides a 5-volt reference to the Passlock data circuit. The BCM provides ground to the Passlock sensor through the Passlock sensor ground circuit. The Passlock sensor interfaces with the BCM through the Passlock sensor data circuit.
When you turn the ignition switch to the START position with the proper key, the Passlock sensor applies a unique resistance value to the Passlock Data Circuit which pulls the 5-volt reference down to a unique voltage value, which is measured by the BCM. This voltage signal is unique and varies from vehicle to vehicle. When you attempt to start the engine, the BCM compares a previously stored (learned) voltage value with the circuit voltage value.
When attempting to start the engine by means other than using the proper key in the ignition switch, the Passlock™ sensor sends a tamper signal to the BCM. The BCM compares the preset stored analog voltage value with the signal coming from the sensor. If the values do not match, the BCM sends a fuel disable password via the Class 2 serial data link to the powertrain control module (PCM). As a result, the PCM disables fuel delivery to the engine.
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's 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 1 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 Class 2 serial data link to disable 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 Class 2 serial data link to enable 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's 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 ten 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 |
