P279D — Four Wheel Drive (4WD) Range Signal Circuit
The 4WD range signal circuit (reporting whether 2H, 4H, 4L is engaged) returns no usable signal.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Four wd range sensor
- Transfer case
- Wiring harness
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Open range sensor or broken signal wire
- Corroded sensor connector
Diagnostic notes
- The malfunction indicator lamp may illuminate
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.