B2725

DTC B2725

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 Descriptor
DTC B2725
- ATC Mode Switch Circuit Malfunction

Circuit/System Description

The range/mode switch circuit consists of 5 modes. The transfer case shift control module supplies 5 volts to the switch through the 5 volt reference circuit. The current travels through the resistor of the active mode. The current is then returned to the transfer case shift control module through the switch signal circuit.

The transfer case shift control module constantly monitors this signal voltage to determine the condition of the mode switch circuit.

When each of the modes are selected they complete a circuit through their own specific resistor. The transfer case shift control module continuously monitors the switch input to determine whether 4HI, AUTO 4WD, 2HI, or 4LO mode was selected.

Conditions for Running the DTC

* The ignition is ON.
* System voltage is 9-18 volts.

Conditions for Setting the DTC

* The system constantly monitors the voltage on the switch signal circuit.
* If the system detects a voltage level under 0.1 volt or greater than 4.9 volts for 2.5 seconds, the DTC is logged.

Action Taken When the DTC Sets

* All shifting is disabled.
* The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle.

Conditions for Clearing the DTC

* The transfer case shift control module clears the current DTC if the condition for setting the DTC is not currently present.
* A history DTC clears after 100 consecutive ignition cycles without a fault present.
* History DTCs can be cleared using a scan tool.

Reference Information
Schematic Reference

Transfer Case Control Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Transfer Case Description and Operation (NVG 226-NP8 - Transfer Case)
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.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.