C0309 Code: Meaning, Causes, and Symptoms | OBD2 Codes
C0309 – Motor A/B Circuit High
C0309 Possible Symptoms
Anti-Lock Brake System (ABS) Warning Light ON,Engine Light ON (or Service Engine Soon Warning Light)
C0309 Possible Causes
Faulty Transfer Case Motor,Transfer Case Motor harness is open or shorted,Transfer Case Motor circuit poor electrical connection
The transfer case motor is a bi-directional, permanent magnet, D.C. motor. When energized, (through Motor Control A or Motor Control B, the ground is provided by the opposing Motor Control circuit and then grounded through the transfer case shift control module ground circuit), the motor, through a series of gears, rotates a shaft which moves the mode and range forks to shift the transfer case between 4H, AUTO 4WD, 2H, N, and 4L ranges. While the transfer case motor is energized the transfer case shift control module also energizes the solenoid for the transfer case lock. The motor lock is disabled (locking action released) and free turning of the transfer case motor and sector shaft is then allowed. This DTC detects a short to ground in Motor Control A or Motor Control B CKT.