GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Colorado Pickup - 2WD 🢒 Safety and Security 🢒 Immobilizer 🢒 DTC B2960

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B2960: Security System Sensor Data Incorrect but Valid

Circuit/System Description

The Passlock™ system is provided in order to prevent vehicle theft if the ignition lock cylinder is forced to rotate. The Passlock™ controller reads the coded Passlock™ data signal. The data consists of a voltage generated by a voltage divider network created between the Passlock™ assembly and the Passlock™ controller. If the data is correct, indicating rotation of the lock cylinder with the proper mechanically cut key, then the Passlock™ controller sends a password to the powertrain controller via serial data to indicate that engine starting should be allowed. The Passlock™ controller also interfaces with the driver displays subsystem to indicate, via the security indicator, the Passlock™ subsystem status and acute subsystem failures.

Conditions for Setting the DTC
    • The body control module (BCM) will inspect for a valid code when the ignition is rotated from ON to CRANK and will continue to monitor the signal during the engine running period.
    • The BCM is reading a valid but different code value than previously learned form the Passlock™ sensor.

Action Taken When the DTC Sets
    • The vehicle will not start if the fault occurs before you start the vehicle. The security indicator will be FLASHING.
    • If the vehicle is running when the fault occurs, the BCM will be in the fail enable mode allowing the vehicle to start and run. The security indicator will be ON.

Conditions for Clearing the DTC
    • The DTC will clear once an ignition cycle occurs without the fault recurring.
    • The BCM history codes will clear once 100 concurrent ignition cycles occur without the fault recurring.
    • The DTC can be cleared by using a scan tool.

Diagnostic Aids
    • Use a scan tool in order to inspect the Passlock™ data voltage and the Passlock™ code.
    • Inspect for poor connections at the Passlock™ sensor.

Reference Information

Schematic Reference

Immobilizer Schematics

Connector End View Reference

Master Electrical Component List

Description and Operation

Immobilizer Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Testing
  1. Install the scan tool. Attempt to CRANK but do not start the vehicle and release the ignition switch to ON. Verify DTC B2960 is set as current.
    2. ⇒If DTC B2960 is set as current along with DTC B2957, B2958 or B3033, proceed to diagnose DTC B2957 , DTC B2958 or DTC B3033 .
  2. Perform the Programming Theft Deterrent System Components procedure.
  3. If DTC B2960 is current a problem exists with the Passlock™ sensor and/or the wiring harness.
    4. ⇒Inspect for poor connections at the Passlock™ sensor. Make the appropriate repair.
    ⇒Replace the ignition and start switch. Refer to Repair Instructions.
  4. Perform the Programming Theft Deterrent System Components procedure.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Ignition and Start Switch Replacement
    •  Control Module References for BCM replacement, setup, and programming