Engine

P03EF — Camshaft Profile Actuator C Control Performance/Stuck Off, Bank 1

Severity: medium Drive with care, to a shop

What P03EF means

The ECM controls a camshaft profile (phasing) actuator to change valve timing or lift based on load and engine speed. P03EF sets when the actual response of the Bank 1 actuator does not match the command, or it stays in the off position. The cause may be the actuator or its solenoid, wiring, oil supply or the camshaft position signal.

Symptoms

  • Check engine light on
  • Reduced power and sluggish acceleration
  • Rough or unstable idle
  • Worse fuel economy
  • Possible hesitation or noise when load changes

Possible causes

  1. Faulty camshaft profile actuator or its solenoid
  2. Damaged wiring: open, short, corroded or loose connector
  3. Low, dirty or wrong-viscosity oil, or a clogged oil passage or solenoid screen
  4. Faulty camshaft position sensor
  5. ECM software or internal fault (uncommon)

How to diagnose

  1. Scan all codes and freeze frame data and note any related cam or crank sensor codes
  2. Check oil level and condition, and change it to the correct spec if needed
  3. Inspect the Bank 1 actuator connector and harness for chafing, oil contamination and corrosion
  4. Measure solenoid resistance and compare with the spec for your engine
  5. Check power, ground and the control signal at the connector with a multimeter or scope
  6. Compare commanded and actual cam position with a scan tool and run an actuator test
  7. Check the camshaft position sensor and timing correlation if a stretched chain is suspected
  8. Check for ECM software updates

Common fixes

  • Replace the camshaft profile actuator or solenoid
  • Repair wiring and connectors
  • Change oil and filter and clean the solenoid screen and oil passages
  • Replace the camshaft position sensor if confirmed faulty
  • Update or replace the ECM only after other causes are ruled out

Questions and answers

Can I drive with P03EF?

For a short time, such as to a shop, yes, but power will be down and fuel use and emissions will rise. Don't put off diagnosis for long.

What most often causes P03EF?

Most often it is the actuator or solenoid, or a wiring or oil problem. Start with oil level and condition and a connector inspection.

Can I just clear the code?

Clearing it turns the light off briefly, but the code will return if the cause is still there. Find and fix the fault first.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.