P2772 indicates the powertrain control module (PCM) has detected a range or performance issue in the four-wheel-drive low-range switch circuit. The switch signals when the transfer case is engaged in low range, and the PCM expects the signal voltage or resistance to stay within a calibrated window. When the signal falls outside that window or behaves erratically, the code sets.
The switch contacts wear or contaminate, sending an out-of-range voltage or resistance to the PCM.
Chafed, corroded, or loose wires and terminals create high resistance or intermittent signals.
Internal shift fork, sector gear, or encoder ring damage prevents the switch from reaching its proper position.
An outdated calibration may misinterpret a valid switch signal; a reprogram may resolve it.
Rare; the control module's input driver or logic fails, but only after wiring and switch are verified good.
The vehicle remains drivable in 2WD or 4WD high, but low range will be unavailable or unreliable; off-road use should be avoided until repaired.
No. The switch, wiring, or transfer case mechanicals are far more common; PCM failure is rare and should only be considered after all other causes are eliminated.
Clearing only turns off the light; the underlying circuit or mechanical fault will cause the code to return once the 4WD low switch is cycled.
P2772 is not an emissions-related code, so it typically does not cause an OBD-II readiness failure, but the check engine light will cause a visual inspection failure in many jurisdictions.