DTC B3935
Diagnostic Instructions
DTC Descriptor
DTC B3935 00: Transponder Authentication Error
Circuit/System Description
When an ignition key is inserted into the transmitter slot and the ignition mode is changed, the transponder embedded in the head of the key is energised by the exciter coils surrounding the ignition lock cylinder. The energised transponder transmits a signal that contains its unique value, which is received by the body control module (BCM). The BCM then compares this value to a value stored in memory. If the value is not correct, the BCM disables engine start.
Conditions for Running the DTC
| • | Ignition is in the Accessory or Run position. |
| • | A valid transponder value has been read. |
Conditions for Setting the DTC
| • | The transponder value is valid and matches the value stored in the BCM memory. |
| • | The transponder calculation of the challenge from the BCM does not match the BCM calculation. |
Action Taken When the DTC Sets
| • | Vehicle starting will be disabled. |
| • | The security indicator will illuminate. The driver information centre will display a service message. |
Conditions for Clearing the DTC
| • | A current DTC will be cleared when a valid transponder value has been read and authenticated. |
| • | A history DTC will be cleared after 100 malfunction-free ignition cycles. |
Reference Information
Schematic Reference
Immobiliser Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Immobiliser Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Replace the suspected inoperative or malfunctioning key.
- Verify DTC B3935 is not set as current.
| ⇒ | If the DTC is set as current
|
| ⇓ | If the DTC is set as history
|
- All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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