锟斤拷 If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC
control module.
3. Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal 1 and low reference circuit terminal 2.
锟斤拷 If less than the specified range, test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the
HVAC control module.
锟斤拷 If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the HVAC control
module.
4. If all circuits test normal, test or replace the evaporator air temperature sensor.
Component Testing
1. Test the evaporator air temperature sensor by varying the sensor temperature while monitoring the sensor resistance.
2. Compare the readings with the Sensor Resistance Table (See: Heating and Air Conditioning/Specifications/Electrical Specifications) and
verify that the resistance is within 5 percent of the specification.
锟斤拷 If not within the specified range, replace the sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Air Conditioning Refrigerant Temperature Sensor Replacement (See: Heating and Air Conditioning/Refrigerant Temperature Sensor/Service
and Repair/HVAC - Automatic)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for HVAC control module replacement, setup, and
programming
B3935
DTC B3935
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC B3935 57
- Transponder Authentication Error
Circuit/System 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. This stored value is the
learned key code. If the value is correct, the TDM will send the prerelease password via the serial data circuit to the engine control module (ECM).
If the transponder value does not match the learned key code or a transponder value is not received, the TDM will send the start disable password to
the ECM.
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 TDM memory.
* The transponder calculation to the challenge from the TDM does not match the TDM calculation.
Action Taken When the DTC Sets
* Vehicle starting will be disabled.
