P03EF code meaning
A Camshaft Profile Actuator C Control Performance/Stuck Off Bank 1
Powertrain system Generic code P03xx codes Check engine light
What P03EF means
With a sliding camshaft, the intake camshaft (camshaft A) 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). P03EF 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.
P03EF at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 6 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P03EF
- 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
Common causes of P03EF
- Most 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)
- Less likelyCam piece sticking or shift groove worn
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Camshaft profile actuator c intakeSliding camshaftActuator wiringEngine control module
What each part of P03EF means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 3 | Area: ignition system or misfire. |
| EF | The exact fault in that area. |
What to do next
- Note P03EF and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P03EF
What does P03EF mean?
P03EF means "A Camshaft Profile Actuator C Control Performance/Stuck Off Bank 1". With a sliding camshaft, the intake camshaft (camshaft A) carries movable cam pieces with several lift profiles; solenoid actuators shoot a pin into a groove in the piece and shift it axially. It is a generic code, so it means the same on every make.
Is it safe to drive with P03EF?
Drive gently and only to a workshop. With P03EF the car can go into limp mode (reduced power) to protect itself.
Will P03EF fail an emissions test?
Yes, it can. P03EF is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P03EF to fix?
Difficulty: medium. A typical repair takes 0.5 to 6 hours of work. This is a job for a workshop.
Will P03EF clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.