B2960

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

Schematic:

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 data voltage signal sampled by the BCM on the PASSLOCK sensor data circuit is one of 9 valid but incorrect PASSLOCK sensor voltage signals. This indicates an invalid PASSLOCK signal.
^ This condition must be present during an engine start attempt, or for one second anytime after the engine has started.

ACTION TAKEN WHEN THE DTC SETS
The BCM will take one of two actions:
1. If the PASSLOCK sensor data voltage signal sample is out of range when attempting to start the vehicle, then the BCM performs the following tasks:
^ Stores DTC B2960 in 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 in order 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, BCM or PCM.

2. If the PASSLOCK sensor data voltage signal sample is out of range after the vehicle starts, then the BCM performs the following tasks:
^ Stores DTC B2960 in the BCM memory
^ Enters fail-enable mode
^ Sends a message to the instrument cluster to turn on the SECURITY indicator
^ Upon subsequent engine start attempts, the BCM sends a message to the PCM via Class 2 serial data link to enable the crank relay, and to deliver fuel to the engine.

CONDITIONS FOR CLEARING THE DTC
^ A current DTC B2960 clears when the BCM detects the correct data voltage signal on the data circuit to the PASSLOCK sensor.
^ A history DTC clears after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
^ A clear-DTC command from the scan tool

DIAGNOSTIC AIDS
^ The following conditions may cause an intermittent malfunction to occur:
- Excessive resistance in the PASSLOCK sensor data circuit.
- Poor connections at the BCM or the PASSLOCK sensor electrical connector. Refer to Testing for Intermittent and Poor Connections in Diagrams.
^ If the PASSLOCK sensor data voltage signal is incorrect, the BCM will not communicate with the PCM to enable the crank relay and to enable fuel delivery to the engine. This vehicle disable period state will last approximately 10 minutes and the SECURITY indicator will flash when the ignition switch is ON. Disconnecting the battery will not clear the timer sequence, which will resume when battery power is restored. Even if a proper data circuit voltage signal is read from the PASSLOCK sensor 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 now start if the BCM detects the correct data circuit voltage signal from the PASSLOCK sensor.
^ 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. If the DTC is a history DTC, the problem may be intermittent. Refer to Testing for Intermittent and Poor Connections in Diagrams.
^ DTC B2958 may set in the BCM when the ignition switch is ON and the PASSLOCK sensor electrical connector is disconnected. When the BCM diagnostics and repairs are completed for DTC B2960, clear the BCM DTCs and perform the BCM Diagnostic System Check. Refer to A Diagnostic System Check - Theft Deterrent.
^ DTC P1626 will set in the powertrain control module (PCM) when the ignition switch is ON and the body control module (BCM) is disconnected. When you have completed the BCM diagnostics and repairs, refer to A Powertrain On Board Diagnostic (OBD) System Check (3.4L) or A 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.
1. Always perform the Theft Deterrent diagnostic system check before attempting to diagnose this DTC.
3. This DTC may set when the Theft Deterrent Re-Learn procedure was not performed after a ignition lock cylinder assembly replacement.
4. DTC B2958 identifies an open or short to B+ in the PASSLOCK sensor data circuit.
5. Tests for power to the PASSLOCK sensor.
6. Tests for a faulty BCM not grounding the PASSLOCK sensor.
7. Tests for an open in the PASSLOCK ground circuit.
8. Tests for an open in the PASSLOCK power circuit.
9. Determines whether the BCM is not properly reading the voltage signal from the PASSLOCK sensor.
10. Determines whether the PASSLOCK sensor is faulty and not due to excessive voltage level sample in the PASSLOCK sensor data circuit.