The Neutral indicator circuit consists of an ignition 3 voltage circuit and a Neutral indicator control circuit. When the Neutral mode has been selected by the driver, 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.
This diagnostic procedure supports the following DTC:
DTC B0790 Transfer Case Neutral Indicator Circuit Malfunction
• | The ignition is ON. |
• | The system voltage is 9-18 volts. |
• | 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 more when the Neutral indicator is commanded, the DTC is logged. |
The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle.
• | The transfer case shift control module will clear the DTC if the condition for setting the DTC is not currently present. |
• | A history DTC will clear after 100 consecutive ignition cycles without a fault present. |
• | History DTCs can be cleared using a scan tool. |
The numbers below refer to the step numbers on the diagnostic table.
This step inspects for the visual operation of the Neutral indicator Light. Command both the ON and OFF states.
This step tests for voltage at the Neutral indicator feed side of the transfer case select switch.
This step verifies that the transfer case shift control module is providing ground to the Neutral indicator.
This step tests if ground is constantly being applied to the Neutral indicator.
This step tests the control circuit of the Neutral indicator for a short to voltage or an open.
This step tests the control circuit of the Neutral indicator for a short to ground.
Step | Action | Yes | No |
---|---|---|---|
Schematic Reference: Transfer Case Control Schematics Connector End View Reference: Transfer Case Control Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
Does the Neutral Indicator Light turn ON and OFF with each command? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | |
Does the DMM indicate battery voltage? | Go to Step 4 | Go to Step 10 | |
Does the DMM indicate battery voltage and then 0 volts with each command? | Go to Step 8 | Go to Step 5 | |
Does the DMM continue to indicate battery voltage with each command? | Go to Step 7 | Go to Step 6 | |
Test the neutral indicator control circuit for a short to voltage or an open. Refer to Testing for Continuity and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 9 | |
Test the control circuit of the neutral indicator for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 9 | |
8 | Inspect for poor connections at the transfer case shift control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 11 |
9 | Inspect for poor connections at the harness connector of the transfer case shift control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 12 |
10 | Repair the ignition 3 voltage circuit of the transfer case select switch for an open, a high resistance, or a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 13 | -- |
11 | Replace the transfer case select switch. Refer to Transfer Case Shift Control Switch Replacement . Did you complete the repair? | Go to Step 13 | -- |
12 | Replace the transfer case shift control module. Refer to Control Module References for replacement, setup, and programming. Did you complete the repair? | Go to Step 13 | -- |
13 |
Does the DTC set? | Go to Step 2 | System OK |