B0790

DTC B0790

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 B0790
- Transfer Case Neutral Indicator Circuit Malfunction

Circuit/System Description

The neutral indicator circuit consists of an ignition 3 voltage circuit and a neutral indicator control circuit. When the neutral mode is selected, current is supplied to the neutral indicator by the ignition 3 voltage 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. This DTC detects an open, short to ground or a short to voltage.

Conditions for Running the DTC

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

Conditions for Setting the DTC

* The system monitors the voltage on the neutral indicator control circuit.
* If the system detects a voltage of 3 volts or less for 1.5 seconds when the neutral indicator is not commanded, the DTC is logged.
* If the system detects a voltage of 4.5 volts or greater when the neutral indicator is commanded, the DTC is logged.

Action Taken When the DTC Sets

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 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.