B2960
DTC B2957, B2958, B2960, or B3033
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptors
DTC B2957
- Security System Sensor Data Circuit Low
DTC B2958
- Security System Sensor Data Circuit High
DTC B2960
- Security System Sensor Data Incorrect but Valid
DTC B3033
- Security System Indicates Tamper
Diagnostic Fault Information
Circuit/System Description
The immobilizer system determines whether engine starting will be allowed based on a pull-down voltage created by the security resistor located in the ignition switch. When the ignition is in the START position, 5 volts is applied to the security resistor by the body control module (BCM) via the ignition key resistor signal circuit. A ground path is provided back to the BCM by the off/run/crank voltage circuit. This circuit is also used in power moding operations. With the ignition in the START position, a voltage value is produced on ignition key resistor signal circuit based on the resistance of the security resistor. Each available resistor will produce a unique voltage value seen at the BCM. During immobilizer programming, the BCM learns this voltage value. On a start attempt, the BCM will compare actual voltage seen to the learned value. If the voltage seen and the learned value do not match, vehicle starting will be disabled.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
B2957
The voltage value seen at the BCM on the ignition key resistor signal circuit is less than 0.4 volts for 1 second.
B2958
The voltage value seen at the BCM on the ignition key resistor signal circuit is greater than 4.8 volts for 1 second.
B2960
The voltage value seen at the BCM is valid, but does not match the stored value.
B3033
The voltage value seen at the BCM is invalid and indicates a tamper condition.
Action Taken When the DTC Sets
* Vehicle starting will be disabled.
* The security indicator is illuminated.
B3033
The BCM will enter the tamper state. Any attempt at starting will be ignored for a period of 10 minutes.
Conditions for Clearing the DTC
* A current DTC will clear when the fault is no longer present.
* A history DTC will clear after 100 concurrent malfunction free ignition cycles.
Reference Information
Schematic Reference
Immobilizer Schematics (Immobilizer Schematics)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Immobilizer Description and Operation (North America, except Canada) (Immobilizer Description and Operation (North America, except Canada))Immobilizer Description and Operation (Canada, Europe, Middle East, and Asia) (Immobilizer Description and Operation (Canada, Europe, Middle East, and Asia))
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
B2960
Perform the 10 Minute Vehicle Key Relearn procedure. The BCM should successfully learn the voltage value and DTC should clear.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the ignition switch.
2. Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal 5 and ground.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
3. Ignition OFF, connect the harness connector at the ignition switch. Disconnect the X2 harness connector at the BCM.
4. Ignition in the CRANK position, test for 10-18k ohms between the signal circuit terminal A42 and the ignition voltage circuit terminal A14.
• If greater than the specified range, test the voltage circuit for an open/high resistance. If the circuit tests normal, test or replace the ignition switch.
• If less than the specified range, test or replace the ignition switch.
5. Connect the X2 harness connector at the BCM.
Important: Do not start the vehicle. Observe the parameter while momentarily placing the ignition switch in the CRANK position.
6. Ignition in the CRANK position, verify the scan tool BCM Ign. Off/Run/Crank parameter is Active.
• If not the specified value, test the ignition voltage terminal A14 circuit for a short to ground. If the circuit tests normal, replace the BCM.
7. If all circuits test normal, test or replace the ignition switch.
Component Test
1. Ignition OFF, disconnect the harness connector at the ignition switch.
2. With the switch in the OFF position, test for infinite resistance between the ignition voltage terminal 4 and the signal terminal 5.
• If less than the specified value, replace the ignition switch.
3. With the switch in the RUN position, test for less than 10 ohms between the ignition voltage terminal 4 and the signal terminal 5.
• If greater than the specified range, replace the ignition switch.
4. With the switch in the CRANK position, test for 10-18k ohms between the ignition voltage terminal 4 and the signal terminal 5.
• If not within the specified range, replace the ignition switch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Ignition and Start Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming