NVG 136-NP4 (One Speed Automatic)

DTC C0309 Motor A/B Circuit High
Circuit Description
The transfer case encoder motor is a permanent magnet DC motor and gear reduction assembly. The encoder motor is controlled with a pulse width modulated (PWM) circuit within the transfer case shift control module. This circuit consists of a power supply relay (Motor A) circuit that supplies voltage to the motor through CKT 1552. The Motor B circuit (CKT 1553) is a PWM driver that varies the duty cycle to control the amount of current through the motor to ground.
This DTC detects a short to power on CKTs 1552 and 1553.
Conditions for Setting the DTC
^ The system will test the motor circuits by checking for unwanted voltage.
^ The system supplies voltage on the Motor A circuit and reads the voltage back on the Motor B circuit.
^ The transfer case shift control module senses a high voltage return on CKTs 1552 or 1553 when a low voltage is expected.
^ If the system detects a problem with the circuits, the DTC is logged.
Action Taken When the DTC Sets
^ All clutch activation (slip control) will be disabled.
^ The SERVICE indicator (AWD/4WD) lamp will be latched on for the remainder of the current ignition cycle.
Conditions for Clearing the DTC
^ Current DTC
The transfer case shift control module will clear the DTC if the condition for setting the DTC no longer exists.
^ History DTC
- Once 100 consecutive ignition cycles without a fault present.
- You issue a scan tool CLEAR CODES command.
Test Description
The number(s) refer to the step number(s) on the diagnostic table.
2. This step determines if there is a short to voltage on CKT 1552.