B3935

DTC B3935

Circuit Description

When an ignition key is inserted into the ignition lock cylinder and the ignition is switched ON, the transponder embedded in the head of the key is energized by the exciter coils surrounding the ignition lock cylinder. The energized transponder transmits a signal that contains its unique value, which is received by the theft deterrent module (TDM). The TDM then compares this value to a value stored in memory, learned key code. If the value is correct, the TDM sends a random generated number to the transponder. This is called a challenge. Both the transponder and the TDM perform a calculation on the challenge. If the calculations match, the TDM sends the fuel enable password via the serial data circuit to the powertrain control module (PCM). If either the transponders unique value or the calculation to the challenge is incorrect, the TDM will send the fuel disable password to the PCM via the serial data circuit.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B3935 Transponder Authentication Error

This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description. DTC Symptom Description






Conditions for Running the DTC

* The ignition switch is in the ACCESSORY or RUN position.
* DTC B1325 03 or B1325 07 is not current.

Conditions for Setting the DTC

* The transponder value matches the value stored in the TDM memory.
* The transponders calculation on the challenge from the TDM does not match the TDM calculation.

Action Taken When the DTC Sets

* The vehicle will not start.
* The TDM sends a message via the serial data circuit to the body control module (BCM) to flash the SECURITY indicator.

Conditions for Clearing the MIL/DTC

* The TDM clears the current status of the DTC when the transponders calculation on the challenge matches the TDM calculation.
* The TDM clears the history status of the DTC after 100 fault-free ignition cycles.
* The DTC can be cleared by using a scan tool.

Test Description

Step 1 - Step 6:

The numbers below refer to the step numbers on the diagnostic table.
. This step verifies the conditions for setting DTC B3055 or B3060 are not current.
3. If a new key must be tried, the key must have the proper mechanical cut and the theft deterrent control module must learn the transponder value.
4. If the replacement key does not work, the theft deterrent control module must be malfunctioning.