TCCM - Mode Switch Circuit
1. Key ON, engine OFF. Install the TCSCS.
2. Using the Data Display feature of the scan tool, monitor the Mode Switch Supply and Return Voltages while turning the TCSCS through each
mode.
锟斤拷 If the voltage is less than the specified value, test the affected circuit for an open/high resistance, short to ground or short together. If all
circuits and connections test normal, reprogram the TCCM. If the DTC resets replace the TCCM.
锟斤拷 If the voltage is greater than the specified value, test the affected circuit for a short to voltage. If all circuits and connections test normal,
reprogram the TCCM. If the DTC resets replace the TCCM.
3. Perform the Circuit/System Testing.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Transfer Case Shift Control Switch Replacement (Without SLT) (See: Powertrain Management/Transmission Control Systems/Sensors and
Switches - Transmission and Drivetrain/Sensors and Switches - Transfer Case/Four Wheel Drive Selector Switch/Service and Repair)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for TCSCM replacement, setup, and programming
* Transfer Case High/Low Clutch Reset (See: Transmission and Drivetrain/Transfer Case/Testing and Inspection/Symptom Related Diagnostic
Procedures/MP 3023/3024-NQH - Transfer Case/Transfer Case High/Low Clutch Reset)
MP 3023/3024-NQH - Transfer Case
DTC B2725
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 B2725 08
- Active Transfer Case (ATC) Mode Switch Signal Invalid
Diagnostic Fault Information
Circuit/System Description
The active transfer case mode switch circuit consists of 5 modes. The transfer case shift control module (TCCM) supplies a regulated 5 volts to the
switch through the 5-volt reference circuit. The current travels through the specific resistor of the currently selected mode - each mode has its own
resistor. The current is then returned to the TCCM through the switch signal circuit.
The TCCM continuously monitors the switch signal circuit to determine whether a mode change has been requested by the driver.
The NQH transfer case has the following 5 modes:
