Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC B2725 08: Active Transfer Case Mode Switch CircuitDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Invalid |
|---|---|---|---|---|
Active Transfer Case Mode Switch Circuit | DTC B2725 08 | DTC B2725 08 | DTC B2725 08 | DTC B2725 08 |
Circuit/System Description
The active transfer case 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 travel through the resistor of the currently 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 the Neutral, AWD, 2HI, 4HI, or 4LO mode was selected by the driver.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | System voltage is 10.5-18 volts. |
Conditions for Setting the DTC
| • | The system constantly monitors the voltage on switch signal circuit. |
| • | If the system detects a voltage level under 0.38 volts or greater than 4.86 volts for 60 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 DTC if the condition for setting the DTC is not currently present. |
| • | A history DTC clears after 40 consecutive warm up cycles without a fault present. |
| • | History DTCs can be cleared using a scan tool. |
Reference Information
Schematic Reference
Transfer Case Control Schematics
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Diagnostic Aids
A short to ground on the neutral indicator control circuit will cause the neutral indicator to remain on at all times. An open or high resistance will cause the neutral indicator to be inoperative during the 2 second bulb check.
Circuit/System Testing
The 5-volt reference circuit and the switch signal will have to be checked for shorts to ground, opens, high resistance, and shorts to voltage by following the below listed steps.
- Reference the mode switch supply voltage with a scan tool.
- If the mode switch return does not read 4.8-5.2 volts check the switch signal circuit and the 5-volt reference circuits for a short to ground, short to voltage, open, or high resistance.
| ⇒ | The scan tool should indicate 4.8-5.2 volts. If the scan tool indicates the voltage is within this specification then with a jumper wire short the switch signal circuit pin 12 on the switch to the 5-volt reference circuit pin 11 on the switch. If the mode switch return voltage on the scan tool measures 4.8-5.2 volts then replace the switch. |
| ⇒ | If no shorts or high resistance are found on the switch signal or 5-volt reference circuits then replace the transfer case shift control module, reprogram, and complete the motor learn procedure. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for TCSCM replacement, setup, and programming |
