New Diagnostic Steps Added for 4WD Front Axle Disconnect DTCs C118D, C10BA, C116F and C119C
GM Engineering has identified a previously missing connector interface that requires inspection and circuit verification if a vehicle is serviced for any of the 4WD Front Axle Disconnect DTCs that may set on 2020-2026 Silverado 2500HD/3500HD and Sierra 2500HD/3500HD models and 2023-2026 Colorado and Canyon models.
Service Information for DTCs C10BA (Secondary Axle Motor Relay Control), C116F (Four Wheel Drive Wheel Lock Indicator), C118D (Front Axle Actuator Control) and C119C (Signal Incorrect After Event) has been updated with additional circuit/system inspection and verification steps in order to accurately identify the root cause of each DTC.
- On Silverado and Sierra models, the X107 inline harness connector interface has been added to Service Information.
- On Colorado and Canyon models, the X415 inline harness connector interface has been added to Service Information. (Fig. 7; #12), (Fig. 8)
Fig. 7
Fig. 8
Wiggle Test
Due to the potential for intermittent failure with these interfaces, a “wiggle test” has been added to the circuit/system verification steps, which calls to check for intermittent connections that may be evident only when the vehicle is being driven. (Fig. 9)
Wiggle the harness and connector of the specified components while monitoring the All Wheel Drive and AWD Input-Output Circuit Status parameters on the scan tool. The parameters should not change while wiggling the harness and connector. If the parameters change, repair the wiring or connector as needed.
Fig. 9
For additional information, refer to Transfer Case Diagnostic Information and Procedures in the appropriate Service Information.
– Thanks to Barnabas Bancsov and Fred Brendel
