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How To: NP 246 Transfer Case Codes

Big T

Well-Known Member
Reaction score
Fullerton, CA
Found this method of pulling codes for the transfer case:

For the newer style electronic 4x4 systems in vehicles with OBD-II systems and the shift button between the instrument panel and the radio/HVAC control stack:

The diagnostic trouble codes are displayed on the three transfer case shift select buttons. The shift select buttons are located on the instrument panel. When the connector pin 13 on the data link cable is grounded, and the ignition switch has been OFF for at least five seconds prior to positioning the ignition switch to run the shift select buttons will blink various times together in order to indicate a diagnostic trouble code from 1 to 4.

Position the ignition switch to OFF. Ensure the ignition switch is positioned to OFF for at least 6 seconds.

Connect pin 13 on the data link cable to a vehicle ground source. The data link connector is located in the cab under the instrument panel on the drivers side.

Position the ignition switch to RUN.

Note the shift select buttons for blinking codes.

If the shift select buttons all blink one time and stop, and do not continue to blink, no fault codes are stored in the TCCM. The transfer case shift select buttons will blink in order to identify any stored DTC. If only one code is stored in the TCCM memory, that code will blink repeatedly with a three second delay between blinking sequences. If more than one code is stored, the first code will blink once, then after a three seconds delay, the next code will blink. This sequence will continue until pin 13 is no longer grounded.

When reading the diagnostic trouble codes, the number of shift select buttons blinks will indicate the code number.

Diagnostic Trouble Code (DTC) 1
When the ignition switch is positioned to RUN the TCCM test to determine if RAM standby Power (maintained battery power) to the TCCM was lost since the ignition was last turned OFF. When power is interrupted on pin C6 of the TCCM, the TCCM stores a loss of RAM standby power.

Diagnostic Trouble Code (DTC) 2
During electronic shifting, the TCCM check the motor/encoder for normal operation. If the motor/encoder does not function correctly enough times, the TCCM stores a motor/encoder failure DTC 2.

Diagnostic Trouble Code (DTC) 3
The TCCM performs a test each time the electronic-shift motor is turned ON or OFF. If the motor does not function properly the TCCM stores a motor circuit failure DTC 3, and the shift select buttons blink in order to inform the driver of a problem.

Diagnostic Trouble Code (DTC) 4
Each time the ignition is turned ON, the TCCM tests the memory, the program, and the internal system in order to ensure that the TCCM is operating properly. If the TCCM detects a fault within the TCCM, the TCCM stores a RAM/ROM memory failure (DTC) 4.

When the TCCM is running a diagnostic, and a code 4 is displayed by the shift select buttons, replace the TCCM/

Good luck and keep us posted.