P03EC: A Camshaft Profile Actuator C Control Circuit/Open 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. 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). P03EC means the actuator's control circuit is open: GM checks the circuit with the driver on and sets the code at an impedance of 200 kΩ or more (4 of 5 samples, above 11 V, MIL on the first trip). The actuator can then not shift its cam piece, and lift switching and cylinder deactivation are blocked.

Medium severity. Can I keep driving?Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.

Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank.

Symptoms

Check engine light on
Lift switching and cylinder deactivation blocked, higher consumption
Possibly rough running if a cam piece stays in the wrong position

Most likely causes

Actuator connector loose, corroded or pin pushed back (often after valve cover work)
Actuator solenoid open
Wire broken in the engine harness
Driver in the engine module

What to check, in order

Start with the simplest. You can tick off each step.

Check the oil level and condition before anything else
Check the continuity of the wire between the component and the control module.
Check the solenoid valve's connector
Compare commanded and actual angles in live data
Test the solenoid valve and its filter, if it has one
Check the engine timing if there is chain noise

Good to know

Repair difficulty: medium
It can trigger limp mode.
It affects emissions.

What each character of P03EC means

P: Powertrain: engine and transmission
0: Generic code: same on every make
3: Ignition and misfires
EC: Specific fault in that system

Frequently asked questions

Can I keep driving with code P03EC?

Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.

What causes code P03EC?

The most common causes are: actuator connector loose, corroded or pin pushed back (often after valve cover work); actuator solenoid open; wire broken in the engine harness.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.