B2725

DTC B2725
Circuit 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.

DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2725 ATC Mode Switch Circuit Malfunction

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.





Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step tests for proper operation of the transfer case mode select switch.
3. This step tests the mode switch for proper resistance values in all mode switch states.
4. This step tests the switch signal wire for a short to ground, short to voltage or high resistance.