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 the values match, the BCM sends a fuel enable password via the Class 2 serial data link to the powertrain control module (PCM). The PCM then enables the crank relay, and allows fuel delivery to the engine. |
| • | When 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 the crank relay, and does not allow fuel delivery to the engine. |
Conditions for Setting the DTC
The BCM samples a reference voltage on the Passlock sensor data circuit during engine start up that is a tamper signal; indicating a Passlock tamper.
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 two actions:
- If the BCM programming mode is not active AND the BCM is not in fail enable mode, then the BCM performs the following steps:
- If the BCM programming mode is active AND the BCM is in fail enable mode, then the BCM performs the following steps:
| • | Stores a DTC B3033 in the BCM memory |
| • | Sends a message to the instrument cluster to flash the SECURITY indicator |
| • | Sends a message to the PCM via Class 2 serial data link to disable the crank relay, and stop fuel delivery to the engine |
| • | Disables the sampling of the Passlock sensor data 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. Refer to Programming Replacement Lock Cylinder, Body Control Module or Powertrain Control Module for more information. |
| • | Stores a DTC B3033 in the BCM memory |
| • | Sends a message to the instrument cluster to turn ON the SECURITY indicator. |
| • | Sends a message to the PCM via Class 2 serial data link to enable the crank relay, and to deliver fuel to the engine; allowing the engine to crank and start |
Conditions for Clearing the DTC
| • | A current DTC B3033 clears when the BCM detects a valid data voltage signal on the data circuit. |
| • | A history DTC clears after 100 consecutive ignition cycles if the condition for the malfunction is no longer present. |
Diagnostic Aids
| • | A faulty 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, which will resume when battery power is restored. Even if a proper Passlock sensor data voltage signal 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 changes from a flashing state to a solid on state. At this time, the BCM enters the theft deterrent re-learn mode. Also, the engine will start if the BCM detects the correct Passlock sensor data voltage signal. |
| • | Inspect for poor connections at both the BCM and the ignition lock cylinder assembly, which could cause an open, an incorrect Passlock sensor voltage signal, or an intermittent malfunction. |
| • | DTC B2958 may set in the BCM when the ignition switch is ON and the Passlock sensor electrical connector is disconnected. |
| • | DTC P1626 sets in the powertrain control module (PCM) when the ignition switch is ON and the body control module (BCM) is disconnected. When BCM diagnostics and repairs are completed, refer to Powertrain On Board Diagnostic (OBD) System Check (3.4L) or Powertrain On Board Diagnostic (OBD) System Check (3.8L) in Engine Controls for additional information on PCM related DTCs. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Always perform the Theft Deterrent diagnostic system check before attempting to diagnose this DTC.
-
Test if the tamper condition is currently present or is intermittent.
-
If this DTC resets after replacing the PASSLOCK sensor, then the BCM is faulty.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Was the Theft Deterrent diagnostic system check performed? | -- | Go to Step 2 | ||
2 |
Is the DTC a history DTC? | -- | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 |
Does this DTC reset as a current DTC? | -- | Go to Step 4 | Go to Step 5 | |
Does this DTC reset as a current DTC? | -- | Go to Step 6 | System OK | |
5 | A malfunction is intermittent and not present at this time. Refer to Diagnostic Aids for more information. Is the action complete? | -- | Go to Step 7 | -- |
6 |
Is the repair complete? | -- | Go to Step 7 | -- |
7 |
Are any current BCM DTCs present? | -- | System OK |
