P279D
Four Wheel Drive (4WD) Range Signal Circuit
The 4WD range signal circuit (reporting whether 2H, 4H, 4L is engaged) returns no usable signal.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Open range sensor or broken signal wireCommon
- Corroded sensor connectorPossible
Parts involved
- Four Wd Range Sensor
- Transfer Case
- Wiring Harness
P279D is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.