P2B33: A Camshaft Profile Actuator B Control Circuit/Open Bank 1

P2B33 concerns the second profile actuator on the intake camshaft (camshaft A) of bank 1. Such actuators are solenoids that extend a pin into a groove on a sliding cam sleeve and so move lobes of a different lift under the valves. GM uses the code on the 2.7-litre turbo four L3B (Silverado and Sierra 1500 from 2019), whose sliding cam system has four intake and two exhaust actuators; GM calls this one actuator 2. The ECM energises the output and flags an open circuit when it sees 200 kΩ or more between signal and ground in 4 of 5 samples, with supply above 11 V; MIL on the first trip (Type A). With the sleeve unable to move, lift switching and cylinder deactivation stay locked out. Low and High are P2B34 and P2B35.

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

MIL on after the first drive with the fault
No change of intake lift profile, less pull or higher fuel use depending on the stuck profile
Cylinder deactivation no longer engages

Most likely causes

Connector at the actuator on the camshaft carrier loose, corroded or not latched after valve cover work
Solenoid winding of actuator B open
Control wire broken in the engine harness
Output stage in the engine control module faulty

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 P2B33 means

P: Powertrain: engine and transmission
2: Generic code: same on every make
B: Subsystem depends on the code range
33: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2B33?

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

What causes code P2B33?

The most common causes are: connector at the actuator on the camshaft carrier loose, corroded or not latched after valve cover work; solenoid winding of actuator B open; control 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.