P279FFour Wheel Drive (4WD) Range Signal Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P279F means the wired 4WD range signal is below the lowest valid level. Many transfer cases report their range through a resistor-coded switch or a position sensor that produces a defined voltage for each of high, low and neutral; a reading under the lowest of these bands points to a short to ground, a missing sensor supply or a sensor that pulls the line down. No manufacturer documents P279F publicly; GM's 2008 Two-Mode Hybrid data list the circuit code P279D for the same range information, and CARB 13 CCR 1968.2 requires range checks on such inputs. The high-side fault is P27A0, the plausibility fault P279E. Look for chafed harness sections near the transfer case and exhaust and for corroded connectors before replacing the encoder.
- What you may notice
- 4WD range indicator dark or flashing
- 4WD low or range changes unavailable
- Warning lamp on
- Likely causes
- LikelyRange signal wire shorted to ground near the transfer case
- PossibleSensor reference voltage missing
- PossibleRange switch or encoder failed with low output
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.