• | 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. |
The 4HI indicator circuit consists of an LED dimming supply circuit and a 4HI indicator control circuit. When the 4HI mode is selected, current is supplied to the 4HI indicator by the LED dimming supply circuit, traveling through the 4HI indicator LEDs, at which time the transfer case shift control module supplies the ground through the 4HI indicator control circuit.
• | The ignition is ON. |
• | System voltage is 9-18 volts. |
• | The system monitors the voltage on the 4HI indicator control circuit. |
• | If the system detects a voltage of 3 volts or less for 1.5 seconds when the 4HI indicator is not commanded, the DTC is logged. |
• | If the system detects a voltage of 4.5 volts or greater when the 4HI indicator is commanded, the DTC is logged. |
The SERVICE 4WD indicator is not illuminated.
• | 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 100 consecutive ignition cycles without a fault present. |
• | History DTCs can be cleared using a scan tool. |
Transfer Case Control Schematics
Transfer Case Description and Operation
Control Module References for scan tool information.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.