P03F4B Camshaft Profile Actuator C Control Performance/Stuck Off Bank 1
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- With a sliding camshaft, the exhaust camshaft (camshaft B) carries movable cam pieces with several lift profiles; solenoid actuators shoot a pin into a groove in the piece and shift it axially. Actuator C is the third of these actuators – not a profile position. The only known user is GM's 2.7-litre turbo four (L3B, three-step sliding cam, from model year 2019). P03F4 is the function check: in the standard's wording the actuator does not do what is commanded. A Hall sensor in the actuator reports the pin position. GM uses this code for a pin that extends without being commanded (4 of 5 cylinder events, MIL on the first trip); a pin that does not extend on command shows up there through the cam piece position sensors (GM-specific codes P30BE ff). GM bulletins name swapped actuator connectors and actuators fitted to the wrong camshaft after repairs.
- What you may notice
- Check engine light on
- Ticking or rattling at the camshaft carrier
- Misfire, rough idle or less power in the wrong lift profile
- Lift switching and cylinder deactivation out of service
- Likely causes
- LikelyActuator faulty inside: pin extends uncommanded (weak return spring)
- PossibleActuator connectors swapped, or intake and exhaust actuators fitted to the wrong camshaft
- PossibleInterference in the Hall feedback signal (ground, connector)
- RareCam piece sticking or shift groove worn
- 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: €150 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.