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 B0790 01: Neutral Indicator Circuit Short to BatteryDTC B0790 06: Neutral Indicator Circuit Short to Ground or Open
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Neutral Indicator Circuit | DTC B0790 06 | DTC B0790 06 | DTC B0790 01 | -- |
Circuit/System Description
The neutral indicator circuit consists of a 12 volt reference circuit and a neutral indicator control circuit. When the neutral mode has been selected, current is supplied to the neutral indicator by the 12 volt reference circuit, traveling through the neutral indicator LED, at which time the transfer case shift control module supplies the ground through the neutral indicator control circuit.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | System voltage is 10-18 volts. |
Conditions for Setting the DTC
| • | The system monitors the voltage on the neutral indicator control circuit. |
| • | If the system detects a voltage of 2 volts or less for 1.5 seconds when the 2 high indicator is not commanded, the DTC is logged. |
| • | If the system detects a voltage of 4.5 volts or more when the 2 high indicator is commanded, the DTC is logged. |
Action Taken When the DTC Sets
The SERVICE 4WD indicator is commanded on for this DTC for the remainder of the 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
Check the 12 volt reference circuit pin 2 at the transfer case shift control switch for voltage with the ignition on.
| ⇒ | If less than battery voltage check the 12 volt reference circuit for an open or high resistance. If the voltage is low or non existent and the circuit tests good replace the BCM. If the BCM test good go to the next step. |
| ⇒ | If the neutral indicator is on at all times check the neutral indicator control circuit for a short to ground. If the neutral indicator is inoperative during bulb check, check the neutral indicator control circuit for an open or high resistance or short to voltage. If the circuit checks good continue to the next step. |
| ⇒ | With the ignition on shift the transmission to neutral and using transfer case output controls attempt to command the neutral indicator off and on. If the neutral indicator is still inoperative short to neutral indicator control to ground, if the neutral indicator lights replace the module, program, and complete the motor learn procedure. If the neutral indicator is still inoperative replace the switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for TCSCM replacement, setup, and programming |
